OldInsuranceMaps News

Georeference-a-thons! HistoryForge (New Orleans), UMD, and UIUC

Thu, 30 Apr 2026 17:14:57 -0500

Upcoming Georeferencing Events in New Orleans

Here in New Orleans we are looking forward to two georeferencing events coming right up! For the next two Tuesdays (May 5th & 12th) we’ll be partnering with HistoryForge to host georeference-a-thons at Second Line Brewing, just like we’ve done in the past; these will be our 7th and 8th events here!

These are fairly informal gatherings, with an intro and demo at 6:30, and then socializing and georeferencing to follow. We also hope to have a short presentation about areas we’ll be working on (8th Ward and 12th Ward), though are still ironing out those details.

If you are in the area and would like to attend, please RSVP here: tiny.cc/georef looking forward to seeing some of you next week!

I’d also like to highlight a couple events that other groups have held recently.

Mapping Historical Duluth: A Crazy Long-Term Project You Can Contribute To

At University of Minnesota Duluth, Laure Charleux put together a public history workshop as part of the Twin Ports Festival of History. The event featured not only map georeferencing with OldInsuranceMaps.net, but also a historical photo tagging activity, which proved to be especially popular with attendees! Laure and her students are working on multiple digital history projects here: Duluth Historical GIS.

Engineering Open House at UIUC

Members of the Healthy Regions and Policies lab at University of Illinois, Urbana-Champaign put together a Friday evening map-a-thon as part of the Engineering Open House, 2026. Continuing to work on maps in their area, the group completed the Urbana 1909 atlas (almost 30 layers) as well as maps of some other small towns in the area. Thanks to Gabi, Anya, Marc, and especially Cat for putting this event together!

If you or your organization would like to use OldInsuranceMaps.net to facilitate an event, don’t hesitate to get in touch! I’ve also drafted a page describing these events in general. A comprehensive list of all past events is still in the works though…

Code4Lib 2026 - Video links and other notes

Sat, 25 Apr 2026 17:39:07 -0500

Code4Lib 2026

Early last month I attended Code4Lib 2026 in Philadelphia, and gave a presentation called Old Maps for New Apps: Making and Using Georeferenced Sanborn Maps at Scale. It was a short one, 10 minutes, and while at first I thought I would be too pressed for time to give a full overview of OldInsuranceMaps.net to a new audience, I changed things around from how I usually do them and I’m really happy with how it turned out. Per Code4Lib norms I’ve made my slides available on Zenodo.

I also facilitated an after-conference workshop, Running a Community Georeferencing Event, and five people came to learn about how OIM can be used for collaborative work at community events. We worked on Camden, N.J., 1885, and also a bit on Helena, MT, 1888 where one of the attendees was from. Shoutout to kcamanch1 for completing Camden even after we finished the workshop!

It was my first time at Code4Lib and I really enjoyed it! As I don’t work in a library many of the talks were not especially relevant to my day-to-day endeavors, but I did like seeing topics discussed that I had learned about in grad school, like BibFrame and EAD, and of course the ever-present dilemma of how to handle all of these bot scrapers… I especially enjoyed Brandon Nightingale’s keynote about digitizing historical newspapers at the Black Press Archive (Howard University). “Digitizing is not passive work, it is architecture”, i.e. the structure of a digital archive determines how useful it can be in the future. This is an approach to the work that certainly resonates with me.

Fri, 03 Apr 2026 09:20:46 -0500

Last month I presented at #Code4Lib: www.youtube.com/live/6nBJ… While preparing the slides, 10 minutes was feeling really short (especially for a new audience) but I reworked some things and I think it’s actually the best introductory talk about the project I’ve given!

Newsletter: Winter (pt 2)

Mon, 02 Mar 2026 08:49:38 -0500

This email is (hopefully) finding you via my new setup on Micro.blog. So, so you’ll see a different “from” address. Most importantly, unlike before, you cannot reply directly to this newsletter to get in touch. Please write separately to hello@oldinsurancemaps.net.

Getting out and about

Mapping USA: Video now on YouTube

At the very end of January I co-led a workshop during OpenStreetMap US’s virtual Mapping USA conference, Historical Mapping with OpenHistoricalMap, OldInsuranceMaps.net, and Yesterdays. These are three community-focused history projects that all swirl around the OpenStreetMap ecosystem, and

This week (tomorrow!): Code4Lib

I’m in Philadelphia this week presenting at Code4Lib 2026. If you happen to be attending, make sure to say hello! If not, all the presentations will be streamed on YouTube (more info here), so you can tune in around 9:30 am Eastern Time on Tuesday (tomorrow) to see me. Really looking forward to this!

I’ll also be doing a workshop on Thursday about hosting georeference-a-thons, and this will ultimately yield more information on the main website about that topic, so stay tuned for that.

Hacker News post

Earlier this month someone posted OldInsuranceMaps.net on HackerNews, which was exciting and just a bit stressful, 4,000 visitors in one day, about 100x the normal numbers! Overall it seems like the site held up pretty well, and it was fun to answer some questions in the ensuing discussion.

RSS, anyone??

We have a new code contributor, the first in many years! Josiah added some RSS feeds to the platform, so you can track activity on any maps within a given place. If you haven’t heard anyone mention RSS in the last 10 years, you aren’t alone. It is a protocol for publishing news feeds, but now we just get email notifications for everything. If you are interested in keeping track of what’s going on in OldInsuranceMaps.net without going to the website every morning, then find your place of interest here and click the RSS icon in the top right to get the feed URL. I expect we’ll be making updates to this over the next few months, so please reach out if you have any ideas or feedback.

Upcoming: Mapping USA and Code4Lib

Tue, 27 Jan 2026 13:16:21 -0500

Mapping USA (January 31)

This coming Saturday at 1pm CST I’ll be co-presenting in a workshop at Mapping USA, a free virtual conference organized by OpenStreetMap US. The workshop, Historical Mapping with OpenHistoricalMap, OldInsuranceMaps.net, and Yesterdays will feature demos from me, Jeff of OpenHistoricalMap, and (particularly excitingly) Jacob and Mike from the new project Yesterdays. We’ll be showing how all of these crowdsourced applications are interrelated, for example, how georeferenced maps OldInsuranceMaps.net have been integrated directly into Yesterdays.

Registration is free, so come join us online this Saturday afternoon!

Code4Lib (March 2-5)

I also have a presentation and workshop coming up at Code4Lib 2026 in Philadelphia. This will be my first time at this conference, so I’m especially looking forward to meeting new people in the library world.

Old Maps for New Apps: Making and Using Georeferenced Sanborn Maps at Scale - Main conference presentation (in-person and accessible via online registration)
Running a Community Georeferencing Event - Post-conference workshop (in-person only)

This workshop will be the first time I have designed and presented materials specifically about the “georeference-a-thons” that we here in New Orleans and folks at a number of other organizations have held over the last few years. Preparing for this workshop will yield more documentation and materials around that part of the website, so stay tuned for more updates.

Sat, 27 Dec 2025 22:52:41 -0500

Blog migration completed! I’ve consolidated all past blog posts and newsletters into this single feed on @micro.blog , and replaced the existing blog site at blog.oldinsurancemaps.net. Looks like some strangeness remains with dates on migrated past posts, but overall, success.

Newsletter: Winter 2025

Fri, 12 Dec 2025 13:55:00 -0500

Herein: Updates on the future of OIM, some good ol' tech improvements, new blog post, and community notes. For new readers, welcome! And here are all past newsletters in case one isn’t enough.

2026 and what it will look like

In mid-January, I will be leaving my position at the Healthy Regions & Policies Lab where I have been for the past 2½ years, leading or contributing to elements of meaningful efforts like the SDOH & Place Project, OEPS, and Chives). I’ve worked with wonderful people and learned a LOT, but plan now to return to freelance consulting for a bit through my own company Legion GIS, and figure out what comes next.

With that in mind, I’m beginning to lay the groundwork for upgrades and enhancements to OldInsuranceMaps.net, and in the new year will be looking to 1) solicit one-off funding for specific efforts, and 2) create a new sponsorship model to provide more sustained support. As always, I am also open to larger institutional funding and collaborative opportunities.

Roadmap, a.k.a. wishlist:

Ability to load maps from other collections, an oft-requested enhancement!
A new map “request hub”, to better track community requests and interest in particular volumes
A new and improved web viewer for all maps in a given city
More ways to visualize and explore statistics around the work that has been performed on the site (a small example of this below)
Text extraction and search framework
Comments, favorites, tagging, reporting issues, and other social things

If you or your organization would like to help make one of these happen (or have other ideas), please get in touch! You can reply directly to this email.

Who uses OldInsuranceMaps.net?

The home page now includes a new section, who uses this platform?. I encourage you to check it out, as the list was longer than I even thought (over a dozen orgs and many individuals) and it was gratifying to put together. There are a few other in-progress collaborations that I hope to add soon.

Improvements to the “multimask” interface

I made a few small improvements to the interface that you can use to trim margins of adjacent georeferenced layers, which I call a “multimask” within the platform. Checkout this recent blog post (Re)Introducing the Multimask Interface to learn more about how this works (it has a bunch more animated gifs too!).

Is that… a leaderboard??

Every time we have a georeference-a-thon, some rogue georeferencer or especially competitive couple asks if there is a leaderboard. There kind of was, just a list of all users with numbers on the platform, but it was an old page and took forever to load. Moreover, it always ended up with Ibrahim or Nate or WallyKitty at the top which (while impressive!!) wasn’t very useful for events where new folks were working on one map all together.

So now there is a Stats table scoped to each Map, which you can find within the Summary section. I’m sure this will evolve over time, but for now it is a fun, quick (and sortable) way to see who has been working on content. Also, that original profiles page is now a lot faster.

Since the beginning, I’ve deliberately not gamified this platform. I figured why not see how far we can get without all of that. That said, there is a side of seeing this information that tells the story of who has done the work, which is a core tenant here, so I do hope to add more elements like this in the future. Who knows, maybe we’ll have georeferencing capitáns at some point too.

Faster tile loading

I implemented TiTiler on AWS as a Lambda service, rather then running it in a Docker container on the main server. If any of that makes sense to you, you are probably just surprised it wasn’t already setup that way. Well, now it is!

There are still more tweaks to make (thanks for the tips, Eliot!), but already you should notice that the mosaic previews with 100 layers will load those layers all at once, instead of incrementally which was one of the limitations that came with the previous setup, and kind of a drag.

Community notes

Georeference-a-thons in New Orleans

In mid-September, in collaboration with the Midlo Center for New Orleans Studies we held two back-to-back georeference-a-thons here in New Orleans, and our usual location of Second Line Brewing. Over the course of two evenings, about 30 people came, with only one person coming both nights (shoutout scanlan!). We worked on New Orleans, 1896, vol. 2, and vol. 4. The latter was especially fun because we split the tables into Carrollton, Gretna, Algiers, and 9th Ward.

A huge thanks to everyone for coming out! We focused on these volumes in particular because the UNO archaeology crew had just done work in Duncan Plaza, so Elizabeth shared some slides about the research and what they had found.

MapRVA presents: Yesterdays

A small and mighty team, MapRVA is an OpenStreetMap group in Richmond, VA, and a few months ago they began developing a new community project called Yesterdays. It is a fantastic crowdsourcing application for geolocating historical photographs of Richmond. They have already placed 5,000 photos!

I learned about Yesterdays when they incorporated mosaics of Sanborn maps made in OldInsuranceMaps.net directly into their interface, which has proved an essential point of reference for placing historical photos. They’ve done more georeferncing since to add more layers–John just georeferenced all of 1925, vol. 2 in a couple of days by himself!

That’s all for now, thanks for reading!

You can follow this project on Bluesky @oldinsurancemaps, or for folks on the OpenStreetMap US Slack, find the new #oldinsurancemaps channel.

(Re)Introducing the MultiMask Interface

Sun, 30 Nov 2025 19:00:00 -0500

The “multimask” is a concept in OldInsuranceMaps.net that greatly eases the creation of seamless mosaics from many different georeferenced layers. I recently made some updates to the user interface for this tool, and decided to take the time to provide a better introduction to feature as a whole.

Make me a clean mosaic

To understand how the multimask idea came about, consider that if you georeference all pages in a historical atlas, you’ll get something like this:

This is the historic French Quarter in New Orleans, as shown on 24 georeferenced pages from the Sanborn map, Vol. 2, 1908. As you can see, while each individual layer would look fine on its own, when they are all displayed together in a single web map the margins from each sheet overlap each other. This obscures information on adjacent sheets, and, generally speaking, looks very messy.

Instead, we want to see a seamless mosaic like this, so that we don’t lose information due overlapping pages, and as a single, clean layer, the mosaic becomes much easier to deal with.

Removing the edges is achieved by cropping or masking each layer, but creating these masks is typically very time-consuming and tedious work. OldInsuranceMaps.net uses a multimask to handle the task in a new way, and to understand why we’ll back up a couple of steps to how the overall workflow is put together (or you can just skip to the end of this post to see some nice animated GIFs I made last night).

Cropping vs. splitting & trimming

It’s common in georeferencing workflows to use a two-step process:

Crop the image to remove unnecessary margins
Georeference the cropped image

If you are working with a single standalone map, as opposed to a map that is a single page of a multi-page atlas, then this is a sufficient approach. Set the mask in the beginning, and you’ll very likely have no reason to modify it later.

However, with multi-page atlases, careful and fine adjustments to a mask may be needed after the page has been georeferenced, once you see how it lines up with an adjacent layer. Depending on the details of how the mask is implemented, this crop ➞ georeference workflow may not lend itself well to making iterative adjustments.

Another thing to consider is that it is fairly common to have multiple maps drawn on a single page, especially in these city-wide multi-page atlases. For example, Alexandria, La., 1892 is a Sanborn map with three sheets (shown below), each with a different number of distinct mapped areas: sheet one has four different regions, sheet two has two regions, and sheet three is one full-page map.

It would be nice to deal with these using a pair of digital scissors, cutting or splitting each page until each map region stands on its own. Then each one of these seven pieces can be georeferenced individually.

To recap then, we have 1) a need to handle multiple map regions within a given page, and 2) a need to carefully mask layers after they have been georeferenced, to properly accommodate the edges and masks of adjacent layers. These considerations led to the creation of a three-step workflow:

Split a page: define the individual geographic regions
Georeference each region: create and apply ground control points
Trim the layer: remove margins of each georeferenced region as desired

Instead of crop ➞ georeference, where the first step both defines the region to georeference and determines the final mask, split ➞ georeference ➞ trim fully separates these concerns, as they are now handled on either side of the actual georeferencing operation. While technically adding a step, this granularity actually creates a simpler and more efficient workflow.

Trimming each layer by itself is slow

To facilitate this final trim step, OldInsuranceMaps.net originally implemented a “create a mask” interface that operated on a per-layer basis. Once an item had been georeferenced, you could add a mask (stored as GeoJSON), which allowed you to trim the margins from layers in a manner that was easy to modify and didn’t affect the existing georeferencing work.

Screenshot of trimming interface from Feb 1st, 2022, when the pilot project went live.

However, it didn’t take long to realize that on a layer-by-layer basis this approach was cumbersome and practically unworkable. Even though it was easy to alter masks at any point because they were simply laid on top of the layers (and didn’t alter any files), doing so in an isolated environment provided no useful context for how to position one layer’s mask with regard to that of its neighbor.

Putting it all together: Multimask

Eventually it became clear that there must be a better way to handle this whole trimming thing, and the key came down to changing the conceptual level at which the task was approached (which, as I think about it, is a theme throughout a lot of the platform’s tooling). Instead of trimming each layer one at a time, let’s do them all at once!

In practice, this looks like putting all layers on the map at once (see the messy image at the top of this post) and then selecting a layer, drawing a mask, then selecting the next layer, drawing a mask, and so on. This is more efficient simply because there is no moving between web pages to move on to the next layer, but with the design features shown below, things really start to look different.

Snapping as a core value

One of the main challenges with creating adjacent masks is making sure that they line up exactly with each other. OpenLayers, the web mapping library that OldInsuranceMaps.net uses throughout, has a very nice snapping capability, which is a key feature of the multimask interface.

In the animation above, one sheet still needs to be masked, while all of its neighbors have already been handled. To create the mask for this final layer, you can just click, click, click, snapping to all adjacent vertices. Upon completion (double-click on the last point) a mask is created and applied to the layer immediately. This new mask shares exact vertices with all of its neighbors, guaranteeing seamless coverage and shared boundaries between layers.

Masks make a fabric

Many great things happen when you can use snapping. Not only is it easy to create masks quickly, but once multiple masks share the same vertex, any alterations to that vertex affect each mask.

For example, if four masks share a corner, moving that corner vertex will change all of them at once.

What is that street name?

Fine-tuning the boundaries between different sheets is necessary when there are certain details at the edge of one layer that should be masked around to ensure that important information isn’t lost. Making small adjustments like this is very easy because adding a vertex to a shared boundary automatically applies it to both masks.

In some cases, two neighboring sheets may have the name of the same street in very close proximity to each after they have been georeferenced, so you’ll want to reveal that street name from on layer and hide it from the other.

Using colors for quality control

Until recently, all vertices were white within the multimask interface, but a couple months ago I added something I had had in mind for a while: color-coding. If a vertex stands on its own, it is white, but if it has been snapped to another vertex it is green. This is especially helpful for cleaning up internal vertices that should be snapped together but for some reason haven’t been.

There are plenty of cases in which a vertex will legitimately stand on its own, like an exterior corner, or even internally where edges of sheets don’t actually overlap. But having this new visual cue makes comprehensive cleanup efforts much easier to do.

Some final thoughts

There is still some clunkiness with how the whole interface works, and capabilities I hope to add in the coming year. So stay tuned!
A foundational characteristic of the OldInsuranceMaps.net data model is layersets, not covered here at all, which are thematic categories of cartographic content within a given atlas and the context within which a multimask is created and applied. A topic for a future post…
Creating masks is not only about trimming margins–masks are also precise vector features that define the coverage area of every single layer. These boundaries can by used in many different ways, for example this interactive mosaic demo I made many years ago.
Many thanks as always to the developers behind OpenLayers and this set of extensions, the Crop filter from which makes this whole idea possible.

Newsletter: Fall 2025 - Upcoming Events

Fri, 12 Sep 2025 13:09:00 -0500

Georeference-a-thons in New Orleans

Over the next couple of weeks we’ll be holding two community georeferencing events at Second Line Brewing in New Orleans. If you are in the area, we hope you can make it!

Dates: Tuesday Sept 16th & Tuesday Sept 23rd
Time: 6:30-8:30pm
Location: Second Line Brewing, 433 N Bernadotte St
RSVP Form: https://tiny.cc/georef-2025

As we have in the past, we’re doing these events in collaboration with the Midlo Center and HistoryForge. We’ll be starting work on the 1895 Vol. 2 Sanborn Map (which covers the CBD and more), and, excitingly, Elizabeth from the Midlo Center will also talk about the archaeological work they have been doing this summer in Duncan Plaza. We hope you can join!

Front-end Party!

In early October I’ll be doing a talk and activity for the wonderful Front-end Party software developer meetup here in New Orleans. Exact details TBD (they’ll be here eventually), but I’m really looking forward to getting some hack-a-thon action only weeks after all of these georeference-a-thons. Hopefully we’ll have some fun web maps to share by the end!

That’s all for now!

But, one fun little detail, a couple weeks ago I added “duration” as a column to the Activity page. This is how long someone has the “split” or “georeferencing” interface open when they are performing one of those tasks. Fun to see, eventually I’ll aggregate these durations for average time per sheet, etc. Also, there are sorting and filtering options on that table and many others within the site. Progress, slowly…

Until next time!

Adam

Using GDAL's VRTs for Georeferencing, from "A look inside OldInsuranceMaps.net"

Fri, 08 Aug 2025 18:00:00 -0500

Recently I gave a presentation about OldInsuranceMaps.net for I-GUIDE’s Virtual Consulting Office speaker series and I was able to talk a bit more about the technical details of the platform than I have in the past, which was really fun and a great excuse to make some more diagrams. One element of the system I described is the way that the georeferencing process relies on GDAL’s “virtual raster” driver (i.e. file format), and how this is used for, among other things, the live preview feature of the georeferencing interface. Here’s a short summary of that part of the talk with a few relevant slides. For more, you can view the full recording, or find the slides here (note, I’ve updated some of them a bit since the recording).

The basic georeferencing process, which turns a non-spatial image into a geospatial dataset, works by chaining two VRTs together and then writing out a GeoTIFF (specifically, a Cloud-Optimized GeoTIFF, or “COG”). The first VRT references the original image and embeds the user-submitted ground control points (GCPs). The second VRT references the first VRT, and embeds the warping information (which transformation to use). The final step is a GDAL translation process which turns the warped VRT into an actual COG.

Importantly, a VRT is just a small XML file, so creating one is nearly instantaneous and requires virtually no storage space. In OldInsuranceMaps, they are also disposable, as the actual database stores all of the information that gets embedded into them. They can be recreated on demand and then deleted after they are no longer needed.

With this in mind, the live preview that is presented in the georeferencing interface is created by injecting user-generated information directly into the VRT linkage chain, and updating that information on GCP creation or modification using a feedback loop. Creating this preview is actually very simple, because TiTiler, and MapServer which I used in the original implementation of this feature, can read and tile data directly from a VRT–no need to actually generate a GeoTIFF.

Finally, to create the mosaics that are the ultimate end goal of the entire system, even more VRTs are added. First, on top of the warped VRT a new one is created that incorporates the layer’s mask, drawn by users through a unified, “multimask” interface. Then, all of the cropped VRTs are wrapped up into a single mosaicked VRT (mosiacking is actually what VRTs are most commonly used for), and that final VRT is then translated into a single (sometimes quite large) COG.

There is even more you can do with this concept of chaining VRTs together, for example enabling the support of custom projections during the georeferencing process. Sanborn Maps are all very large-scale, so warping to a non-Web Mercator projection isn’t necessary or useful. But I have implemented and tested this idea out with much smaller-scale maps that were drawn in a non-Mercator projection, and it works flawlessly. I described the concept in more detail in this old comment on GitHub, and hope to properly implement it on the platform someday.

Newsletter: Summer 2025

Tue, 15 Jul 2025 07:38:00 -0500

Hello all! Writing to tell you about a few things that have happened in the last few months, and some upcoming news.

For new readers: Welcome! You can find all past newsletters in the archive. You can also respond directly to this email to say hello, and you’ll find an unsubscribe link below.

Online presentation for I-GUIDE VCO series, tomorrow!

Wednesday 7/16, 11am US Central Time – registration link

Apologies for the late notice. Tomorrow I’ll be giving an online presentation as part of I-GUIDE’s Virtual Consulting Office showcase series. I’m really looking forward to this, as I’ll be able to get into some of the more technical details of the platform, and there should be plenty of time for Q&A as well. Registration is free and open to everyone! Big thank you to Alex Michels for organizing these talks.

Also, next week I’ll be co-presenting in the same forum with my colleagues from the Healthy Regions & Policies Lab about our work on the SDOH & Place Data Discovery application. Come to that one too for something completely different!

Results of a past georeference-a-thon

This past April, Rowan University’s Center for Digital Humanities Research hosted the largest georeferencing event that the site has facilitated to date. Over the course of an afternoon, 50 new people made accounts and georeferenced over 250 layers, covering a number of towns around Glassboro, New Jersey. It really had the server churning, slowed things down a bit for sure, but nothing broke. Read more about it in the Whit.

Website content reshuffle and new Blog

I’ve accumulated content about OldInsuranceMaps.net in a few different places, and web analytics show that no one really looks at it. So, a couple weeks ago I bribed my wife with pizza and we spent some time figuring out how to reorganize. I’ve done my best to see these changes through over the last couple of weekends, and they aren’t complete, but…

New Blog! blog.oldinsurancemaps.net I’ll be transferring all kinds of pieces from different places into this blog, and it’ll be the best place to stay up-to-date on the project and see how it’s developed over time. I put a lot of entries in already (back-posting as if I’d been writing in it for years), and will continue to do that until I can’t think of anything more to add. Let me know if you have suggestions! (This newsletter isn’t going away though.)
More content on the main website A while ago I created about.oldinsurancemaps.net with documentation, background, and guides on it, but that content has remained somewhat obscure and much of it would be better housed directly within the main website itself. So, with a bit of an update to the main site’s structure, I’m beginning to transfer it over and that site will eventually go away. Still a work in progress, but finally on the way.

And a final tech note…

OldInsuranceMaps.net now stores all of its geotiffs in S3 object storage! In other words, there is a lot more space for new maps. This is a backend change that really opens the door for future work… Not a difference you would notice from looking at the website, but for more information you can checkout this blog post (on the new blog!).

That’s all for now, hope to see some of you tomorrow morning,

Adam

Implementing S3 Object Storage

Sat, 28 Jun 2025 19:00:00 -0500

What is S3 Object Storage?

S3 object storage is a protocol developed by Amazon Web Services for handling file storage outside of a normal server environment and “in the cloud” instead. In other words, it’s a simplified way of uploading, downloading, or directly accessing files that are stored in remote “buckets”. In these buckets, storage is (broadly speaking) very cheap and practically unlimited. Many other companies have since adopted the S3 API so their own cloud storage offerings are compatible with it.

Implementing a new storage backend

To this point, OldInsuranceMaps.net has functioned by downloading image files from the Library of Congress (or other sources, in certain contexts) and storing those files on the main server. Once the images are available locally, the splitting, georeferencing, and mosaicking operations are performed directly on those files, creating even more files (ultimately, Cloud Optimized GeoTIFFs) on the server. Really, the entire point the platform is to build tools and workflows around the creation and management of these files.

One downside to this approach is that the server has limited storage space, let’s say about 500gb. This has been plenty for the last few years (especially as I’ve implemented better compression methods over time) but as available space inevitably diminishes, I decided it was finally time to progress to a new storage strategy.

To implement S3 storage for all content in OIM, there were two general tasks:

Update the code base to work with remotely stored content instead of relying on files on disk
Upload all existing content to an S3 bucket

How much existing content? Well, quite a lot. After a big server cleanup effort (this was the first time I had comprehensively dealt with all kinds of orphan files and remnants from past experiments) there were roughly 130,000 files using about 430gb of disk space.

There were also a couple of important constraints to work around:

S3 storage needs to be optional, so that future installations of the code base can run just using local file storage
Gotta keep the site running! There is a bit of operational inertia that must be respected on the platform, now that there is a lot of content on it and people using it everyday. Practically speaking, this means making slow, incremental steps.

Code compatibility

OIM is built with the Django web framework, and there is a solid, standardized way for implementing S3 storage using django-storages. In theory then, the storages plugin could be installed, a switch could be flipped, and violá, Django will read and write to an S3 bucket instead of the local file system.

However, it wasn’t that simple. Due to the fact that a lot of splitting, georeferencing, and mosaicking operations had been built with the expectation of local file storage, some of them failed once S3 got involved. Luckily, GDAL (on which OIM has relied from the start) has a fantastic virtual file system that allows it to read directly from S3 urls, and combining that with another GDAL feature, virtual rasters or VRTs, offered plenty of flexibility to work with. Ultimately, the implementation required rewriting and improving some basic functions at the core of the app, but produced a better code base in the end. If you are interested, you can read all the gory details in this pull request.

Syncing the content

With the code updated, I had only to transfer all files to an S3 bucket and then point the application to it. I chose to use Wasabi, a very cheap S3 storage solution, but the beauty of this upgrade is that the code is provider agnostic–in the future switching to Amazon or Linode S3 Object Storage should be fairly painless.

In the week before the final deployment, I configured aws cli to point to a new backup bucket in Wasabi, and used it to periodically sync the entire set of files from the production server to that bucket. About 100 new files get created everyday, so the sync operation (which only updates new or altered files) was crucial for seamlessly keeping everything up-to-date.

The result

It went well! Since the switch on a Sunday afternoon, all new files have gone straight to S3, and all of the existing interfaces and viewers on the site now run from COGs in S3 instead of through nginx on the server.

One hiccup I encountered was that the setting AWS_QUERYSTRING_AUTH in Django was automatically set to True , causing the URLs that the backend returned to have embedded expiration dates in them. Everything would be fine when I re-generated the lookups (which include saved URLs for things like thumbnails) but then the next day these same URLs would be “unauthorized” and no longer work. Setting AWS_QUERYSTRING_AUTH=False fixed this issue.

Wasabi is very cheap, just $7/month per terabyte, meaning that the 440gb I have in the bucket (doubled if you include the backup bucket) falls within the lowest tier of usage. A very quick back-of-the-envelope calculation shows that if the entire LOC Sanborn Map collection (500,000 sheets resulting in at least 3x that many files) were georeferenced on OIM, storage would be under 7tb ($49/month) or double that with a backup. That seems like a pretty good deal.

I’ve talked about making this upgrade for a while, so it feels good to finally do it. Technically, I could delete all old content from the server and then downgrade it to reduce the monthly bill, but storage was just one of the elements in play, because the splitting and warping processes do benefit from a powerful server, not to mention I still run TiTiler directly on the server as well. All in good time…

Newsletter: 2024 in Review + new features!

Fri, 21 Feb 2025 09:30:00 -0500

Hello and happy second month of the New Year! It is high Mardi Gras season here in New Orleans and I feel like everything is happening at the same time.

For new readers: Welcome! You can find all past newsletters in the archive.

Also, OldInsuranceMaps.net is now on Bluesky, come be our 2nd follower! I’ll post smaller more frequent updates there, and it will also be something people/orgs can tag when they use OIM for events or research. And, don’t forget the discussion forum a great way to connect with other people using OldInsuranceMaps.net.

2024 Stats and Summary

On NYE of 2023 I sent a newsletter with a nice chart of work performed over that year. For 2024, I don’t have anything that nice to offer, but here are some numbers from last year:

New users: 170 (366 total)
Preparation sessions: 23,235 (31,360 total)
Georeferencing sessions: 29,402 (41,514 total)
New Layers: 28,361 (32,362 total)

As you can tell, 2024 far exceeds all work from past years, largely owed to the incredible work of students and staff at the University of Richmond Digital Scholarship Lab, who seem to be georeferencing 24/7. There have been substantial individual efforts as well though:

hayleox in Cincinnati, OH • mrileyowens in Cincinnati, OH (you two should talk!) • ekoparker in Chicago, IL •\r\nsanborn_again1 in Springfield, IL • mhowell in Noblesville, IN • tagifford in Schenectady/Scotia, NY • Gullimapozo in Gary, IN • lablakely in Waco, Austin, and Georgetown, TX • cliftonmr in Cleburne, TX • Pete_Zivkov in Bellingham, WA • and others!

Plus, of course, a handful of georeference-a-thons (more on those below).

Overall, very roughly, I would estimate we have georeferenced over 1/20th of the entire Library of Congress Sanborn map collection (500k documents in the collection, 38k on OldInsuranceMaps, definitely at least 25k of those processed). Wild!

Georeference-a-thons

Many of these since last newsletter in mid-November!

Healthy Regions & Policies Lab @ UIUC: For GIS Day last year (Nov. 20th) I took the Amtrak to Champaign to work with my colleagues at the University of Illinois to have a 2-hour event where we georeferenced Champain and Urbana maps from 1915. We even had two guest speakers over Zoom! See this blog post for more details (and action shots!).
UChicago: Later that day I joined a (very) small group at UChicago, which was kind of perfect because I got to show Parker and Rob around the site in detail. Thanks to Rob for setting this up, on top of all the other GIS Day programming!
OSU - Also on GIS Day, the team at the Ohio State University Libraries hosted their third georeference-a-thon to date, working on maps of Columbus, great to see such a long-term, continued effort there.
Morgan State University + UIUC: The following day, “Post-GIS Day”, we held a collaborative online event between a group at Morgan State led by Dr. Lawrence Brown, and Dr. Marynia Kolak’s Population Geography class at UIUC. Instead of Sanborn maps, we used OldInsuranceMaps.net to georeference FHA Block Data maps from the late 1930’s and 1940’s. Stay tuned for more about this project in the future.
Community Mapping Lab @ University of Georgia: Just a few weeks ago, Dr. Jerry Shannon and team at UGA held an event to georeference Athens, GA maps, and you can read more about their work here. Jerry’s post on Bluesky also has some action shots!

New features

I’d like to highlight a few new/experimental features I’ve added in the last couple of months.

Activity filters: The activity page is the easiest way to see all current and past work that has been carried out on the platform. I’ve added filters so you can only show work on specific maps, within a date range, or by a certain user.
Parcel layer snapping: We found that in San Francisco maps, each individual block must be georeferenced individually. This is not only extremely tedious, but also more difficult because you can’t use street intersections for control points. So, I set up a system where current parcel lines can be added as a reference layer that you can snap your control points to, which not only speeds things up, but also greatly increases the accuracy of contributed work. I wrote a bit about that on the forum. Have added this feature to a couple other cities, but it is still in development.
Allmaps and IIIF support: Just last week/weekend, I finally set up endpoints on the site that will return IIIF Georeference Annotations for any layer or mosaic within OldInsuranceMaps.net, which can be used directly in the Allmaps Viewer. You can read more about the work in this pull request (examples included), and you’ll now see links to “Open in Allmaps Viewer” within OldInsuranceMaps map overview pages. If you aren’t familiar with Allmaps, I strongly encourage you to check it out.

Looking ahead

Colocate2 at Stanford: Next week I am attending a small “unconference” at the David Rumsey Map Center at Stanford. Really looking forward to this and the discussions that will follow, as it is largely focused on institutional georeferencing work, GeoBlacklight, and Allmaps.
Louisiana History Association Annual Meeting: On Sat. March 15th I’ll be participating in a round-table discussion “Mapping the Past: GIS Technology Implementation for Historic Sites” at the annual meeting of the Louisiana History Association, with Elizabeth Williams (Midlo Center at UNO, HistoryForge) and Sarah Waits (archivist at Archdiocese of New Orleans). If you are attending this meeting, please say hello!
Georeference-a-thon at Rowan University: In April, a group at Rowan University will hold a few events to georeference maps in Gloucester County, NJ. Hopefully I’ll be able to pass on another update about this next month.

Thank you!

A big thank you to everyone who continues make this project possible. Especially my colleagues and lab PI Marynia Kolak at UIUC, as well as the team at the URichmond DSL and their partnership with the University of Michigan. Jeff and Minh continue to make OpenHistoricalMap an inviting place to map history (checkout hayleox’s work in Cincinnati, or Pete’s super detail of New Orleans' French Quarter in 1885), which in turn drives people to OldInsuranceMaps.net where they can create Sanborn base layers to digitize from. Finally, thank you for reading this whole thing!

– Adam

Newsletter: GIS Day Events | NACIS | Data Agreement

Fri, 15 Nov 2024 16:30:00 -0500

In case you didn’t know, GIS Day this year is next Wednesday, Nov. 20th, in the middle of Geography Awareness Week. GIS Day was started by the company ESRI (of ArcGIS reknown) many years ago, and I just learned that Ralph Nader was the inspiration behind the day. Of course, there is a lot to GIS beyond Esri, but as someone who learned about the field at the end of my undergrad and never looked back, I love that GIS Day exists and consider it a great “holiday” to promote. Also, what better time to hold historical map crowdsourcing events?

Also, if you skip most of this newsletter, please at least read about the new Data Agreement at the bottom.

Georeference-a-thons of Future

UIUC - Healthy Regions & Policies Lab

Through my work at HeRoP, we will be putting on a georeference-a-thon in Champaign next Wednesday. You can learn much more about it through this Eventbrite link. The event will be in-person, but we have a Zoom option as well (find it at the bottom of the Eventbrite) and we plan to have a couple of short talks via Zoom by researchers who use historical maps. We will be working on Sanborn maps of Champaign and Urbana from 1915, and I’m looking forward to students getting to learn about what their university environs looked like in the past.

University of Chicago Libraries

After our event at UIUC, the University of Chicago Library will also have a georeferencing event starting at 2pm in the afternoon. For more details about this event, stay tuned to OldInsuranceMaps.net Forum, an oft-overlooked-but-full-of-potential discussion space that we have. I’ll be posting all of this information there in the coming days.

Morgan State University - The Black Butterfly Project

In collaboration with Dr. Lawrence Brown and the team at Morgan State, we’ll be doing a non-Sanborn map georeference-a-thon on Nov. 21st. We will instead be working with old FHA Loan maps from the 1930s, which Dr. Brown sought out and scanned at the National Archives in Maryland. We are extremely lucky to be able to support this work, and we’ll finally get to see the site with a different set of maps! You can learn more about this event, and join from afar, through this Eventbrite link.

The Ohio State University Libraries

At the Ohio State University, Josh Sadvari and the team at the library will be putting on another GIS Day Georef-a-thon just like they did last year. This is an in-person event, and part of a full day of GIS talks, all of which look fascinating. Do check it out if you are in the Columbus area!

Georeference-a-thons of Present

Not exactly present, but just a couple days ago the team at the URichmond Digital Scholarship Lab held a competitive georeference-a-thon (the first of its kind with OIM) and it sure looked like a good time! Riley set up a point system for georeferenced content, complete with the option to challenge the quality of another team’s work to reduce their score.

In addition to points for georeferencing, teams also had to do some scavenger-hunting across the 1905 Richmond map to answer questions like “Across N. 11th St. from City Hall is where you can find the ________ HOTEL” , or “Just _east of Shockoe Slip is where you can find _______ COFFEE CO.”

Congrats to the big winners (and some familiar names from the platform!!): ibrahimalkaser, samyoga, bakeunsu, and willguy.

Georeference-a-thons of Past

Finally, we owe a big and belated thank you to everyone that showed up to the events we did with HistoryForge at Second Line Brewing in New Orleans, this past August. It was unexpectedly great to do two weeks in a row because it felt like we built some momentum, even though there were very few people who came both days.

All together, we had about 25 people attend, made it through the entirety of New Orleans, 1908, Vol. 2, and much of Vol. 3 as well. Once these mosaics are completed and trimmed, we’ll be able to add them to the local HistoryForge project, to help with trascribing and mapping historical US Census documents.

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Presentation(s) at NACIS in October

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Last month I traveled to the annual North American Cartographic Information Society meeting, this year in Tacoma, WA, and presented about OldInsuranceMaps.net. The video of the talk is now on YouTube: Handling Complex Content within Georeferenced Historical Atlases. You can also flip through the slides here: tiny.cc/nacis2024-ac. Even though it sounds pretty boring, this was extremely gratifying to put together and present, because it distills what I think is most unique about the platform.

As a lucky bonus, Riley Champine from the URichmond DSL presented in the same session right after me, so I encourage you to watch his talk as well: Using Old Maps for New Insights on America’s Cities. He discusses updates to the lab’s Mapping Inequality project, and near the end has a fantastic demo of their new project Fires of Industry, that is based on the monumental georeferencing effort their students are carrying out using OldInsuranceMaps.net. I heard a few “wows” in the audience when he showed this.

Finally: Data Agreement

As I have written in this newsletter before, I have been working toward being more precise about what happens with user-contributed data on OldInsuranceMaps.net. I have now added a Data Agreement, that states the following (in summary—see linked page for more details):

Two core goals of OldInsuranceMaps.net are:

To facilitate historical map georeferencing and mosaicking in a streamlined and participatory environment
To create publicly accessible datasets that can be used by anyone for any purpose

To that end, OldInsuranceMaps.net collects user-contributed georeferencing data, and insofar as any of this data is copyrightable, users agree that their copyright is waived and CC0 license is applied.

The platform also records the georeferencing-related actions that a user takes while interacting with it, and uses Plausible Analytics to collect general statistics about visitors to the site. No private user information is collected.

I will reiterate as I have said before: If you have already created content on the site, but would not like to have it available under these conditions: Please get back to me and I will help you download it and will then remove it. No problem at all! The files should be very easy to self-host.

Thanks, as always for reading, and hope to see some of you next week!

Adam

"Handling Complex Content within Georeferenced Historical Atlases"

Thu, 14 Nov 2024 19:00:00 -0500

Last month I traveled to the annual North American Cartographic Information Society meeting, this year in Tacoma, WA, and presented about OldInsuranceMaps.net. The video of the talk is now on YouTube: Handling Complex Content within Georeferenced Historical Atlases. You can also flip through the slides here: tiny.cc/nacis2024-ac. Even though it sounds pretty boring, this was extremely gratifying to put together and present, because it distills what I think is most unique about the platform.

Abstract:

While georeferencing a single map is an easy one-off process, applying the work across a whole atlas (or multi-volume set) is a challenging task–especially when pages have multiple insets and the atlas contains more than one category of maps. How do you structure this work, and create cohesive output? This presentation will describe the novel hierarchical approach within OldInsuranceMaps.net, a crowdsourced web georeferencing platform designed around the complexities of Sanborn fire insurance maps. Facilitating the creation of seamless mosaics from this collection has resulted in a robust, abstract workflow that could be applied to any other maps or collections as well.

I made a bunch of diagrams for the presentation using d2, and here is my favorite one:

Newsletter: Fall 2024

Fri, 13 Sep 2024 14:00:00 -0500

Upcoming Georeference-a-thons!

Here in New Orleans we have two public Georeference-a-thons right around the corner! On the next two Tuesdays we will be gathering at Second Line Brewing (as before) from 6:30 to 8:30pm to georeference more New Orleans Sanborn maps for HistoryForge. We did this last summer, and the resulting work has been integrated directly into the HistoryForge platform (as you can see in the link, click the map icon). Having the Sanborn map layers is very helpful for tracking down old US Census records, and makes exploring the city’s history even more engaging. Hope to see you there!

RSVP Form

A big thank you to Elizabeth from HistoryForge for making the flyer!

CC licensing update

Last winter, I wrote about my interest in applying a CC BY license to the work that people have completed on OldInsuranceMaps.net. Since then, I have done much more research on the topic by reaching out to people with experience in other crowdsourcing applications, as well as copyright experts within university libraries. Overall, I’ve found that CC0 will be a better fit for contributed content on the site, which would place individual contributions “as completely as possible in the public domain,” to borrow Creative Commons language. CC0 is the most permissive Creative Commons license, and will allow the use of map content for research, personal, or commercial use. CC BY would require that attribution be given whenever content is used elsewhere, which sounds good in theory but would bring a level of enforcement and legal burden that I am not able to meet in practice.

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More importantly, however, I’ve learned that the data created through the georeferencing process is unlikely to be considered copyrightable in the first place, because the cut-lines, ground control points, and masks are effectively recordation of facts (“this is the boundary of an inset”, “this pixel coordinate corresponds to that lat/long”), and facts cannot be copyrighted. So the language I will be adopting soon will be along the lines of:

“To the extent that contributed content on OldInsuranceMaps.net can be considered copyrightable, a CC0 license is applied."

As before: If you are not comfortable with the work you have contributed being available through such a license, please get in touch with me ASAP. I will happily help you download/save your work elsewhere and remove it from the site.

Other Recent Work…

I have been working a lot in the past few weeks on a big re-modeling project within the database, which I hope to have fully implemented by next week. (But it has been a complex process so we’ll just see how it goes…) You can read these pull request notes for more details on the changes. Some of the outward improvements that this will make possible are:

Grouping mosaics from multiple volumes for better display in the viewer (currently this is kind of a mess for cities with many volumes, like the 10 new ones in New Orleans from the 1951 edition)
A data model that more closely reflects the structure of the IIIF Georeference Extension, laying groundwork for its eventual adaption within the platform
Complete (well, almost complete) removal of the dependency on LOC’s map collection–a big step toward making the system more generic overall.

This is the topic I’ll be presenting about at NACIS next month in Tacoma, so if you are attending the meeting please say hello! Even better, Riley Champine from the University of Richmond’s Digital Scholarship Lab will be in the same session, talking about their work at the DSL, and in part their use of OldInsuranceMaps.net. I think these talks will be recorded, so I’ll be sure to pass links to them on eventually.

All the best,

Adam

Newsletter: Spring and Mid-Summer Updates 2024

Mon, 24 Jun 2024 08:24:00 -0500

Hello! The last newsletter I sent out was over half a year ago, so a lot has happened in the meantime (including: I got married!). I’ll get to most of the updates here, but hopefully will be able to follow-up sooner than later with more. Before going further, I’d like to welcome the 50+ new folks who have registered since the year started. Looking forward to hearing and seeing what you work on! Which is a good segue to the next point…

We have a new Community Forum!

Jeff Meyer at OpenHistoricalMap suggested that we make a dedicated category for OldInsuranceMaps.net within the existing OHM forum. This provides a permanent, external location to have discussions and post about what people are working on. So, please don’t be shy, let us know what cities you are georeferencing (or have worked on in the past :)). Moreover, do you have a city in mind but haven’t been able to georeference it yourself? Use the forum to let us know, maybe someone else would like to work on it with you. All questions and comments welcome!

Recent publications about OldInsuranceMaps.net

Piloting a Sanborn Map Georef-a-thon for GIS Day 2023, WAML Information Bulletin, Western Association of Map Libraries. 2024. Josh Sadvari and Michelle Hooper
- Josh and Michelle hosted a Georef-a-thon last fall at OSU Libraries using OldInsuranceMaps.net, and wrote this great piece about how it went (spoiler: really well!).
Scroll through Time with the Sanborn Fire Insurance Maps, South Richmond News. February 12, 2024. John M. and Riley Champine
- This article in the South Richmond News highlights historical maps on OldInsuranceMaps.net in Richmond, VA, georeferencing work completed by the URichmond DSL.
Toward a Georeferencing Commons: A Crowdsourcing Case Study and the Creation of OldInsuranceMaps.Net (link for open access version), Journal of Map & Geography Libraries, March 2024. Adam Cox.
- Finally, I’ve created an article-length abridgment of my MS thesis, which was the beginning of this whole project.

Stats!

220 cities have at least some maps georeferenced
550 maps (or “volumes”), completed or in-progress across all cities
17,500 individual layers within these maps
230 registered users

So much of this content has been created by staff and students at the URichmond DSL lab. They are doing fantastic work! This must be the largest Sanborn map georeferencing effort that has been undertaken in a public platform, by far.

Other new things

New About website and documentation location https://about.oldinsurancemaps.net
New Github organization for better repository management/namespacing: https://github.com/ohmg-dev
New content about the underlying workflow structure: https://www.ohmg.dev/concepts

Until next time,

Adam

"Piloting a Sanborn Map Georef-a-thon for GIS Day 2023"

Sun, 23 Jun 2024 18:00:00 -0500

Last November, Josh Sadvari and Michelle Hooper hosted a Georef-a-thon at The Ohio State University Libraries using OldInsuranceMaps.net, and wrote this detailed piece about how they prepared for the event, how the platform worked for them, and what kind of engagement their participants got from the experience.

Piloting a Sanborn Map Georef-a-thon for GIS Day 2023, WAML Information Bulletin, Western Association of Map Libraries. 2024. Josh Sadvari and Michelle Hooper

Some nice quotes from the article, that illustrate how the event was able to expand knowledge and appreciation of historical maps:

Very few georef-a-thon participants indicated they had previously used or even heard of Sanborn maps when asked this question during the introduction, which reinforces how such an activity can help in creating awareness of the potential uses of this collection.

The OldInsuranceMaps.net platform provides a low barrier entry point for teaching spatial and data literacy concepts through georeferencing and engaging students in the “process” of geospatial data, illustrating a standalone educational value that was perhaps not envisioned as a specific outcome during the platform’s conceptualization and development but could be one nonetheless

Newsletter: 2023 Year in Review

Sun, 31 Dec 2023 14:39:00 -0500

Hello everyone and welcome to the final newsletter of 2023! It was last January that I made an announcement letting you all know we were back in business here, and since then a lot of wonderful things have come from the project. First, a couple of recent things I haven’t yet told you about…

As always, you can reply with comments or questions directly to this email (it won’t be a “reply all”!), or view past newsletters here.

On Development Seed’s Blog

Over the course of the year I worked with Kiri Carini and Sanjay Bhangar at Development Seed to create a post about OldInsuranceMaps.net, and we finally released it on Dec. 1st: Open Source Spotlight: Old Insurance Maps. This year I completed a transition to using DevSeed’s open source software, TiTiler, to serve all raster layers and because it is typically used for tiling satellite imagery, they were excited to see my use of it for historical maps. The blog post is one of the more detailed things I’ve written about the tech side of the platform, I encourage you to check it out!

On Maps Mania Blog

A few days after that, the Maps Mania blog (which I have followed for a while and I highly recommend to anyone who likes maps) also featured OldInsuranceMaps.net in a nice post, Historical Sanborn Maps of America. Very happy for this exposure, though there’s nothing to make you feel like you need to improve a home page like all of a sudden having a hundred new people look at it :/.

Boring But Very Important: Upcoming CC BY License Implementation

As more institutions have started using the platform to georeference content, it’s time to formalize licensing for content that is created on the site. At its heart, this is a collaborative crowdsourcing platform that facilitates the transformation of, access to, and public engagement with historical map content. With this in mind, I plan to implement the CC BY 4.0 license for all georeferenced content that is created on OldInsuranceMaps.net. Creative Commons licenses offer a formal way to ensure that content is shareable, and the BY extension requires only that attribution be given when the content is used in other contexts. When I finalize this decision with a statement on the website, I’ll provide more info on how to give credit (probably something like “OldInsuranceMaps.net contributors”, a la OpenStreetMap).

Once implemented, the CC BY 4.0 license would be applied to the following (existing and future) content on OldInsuranceMaps.net:

User input data: cut-lines, ground control points, and trim mask coordinates.
Geospatial datasets derived from this data: georeferenced layers and full trimmed mosaics.

Generally, this content is all free and downloadable already, so I see the CC BY 4.0 license as a way to formalize what has already been in place for almost 2 years now.

That said: If you have georeferenced maps on OldInsuranceMaps.net and you do not want this license to be applied to your work, then I have absolutely no problem with helping you download everything you’ve created and then I will remove it from the site.

Finally: If you have experience with CC licenses and/or licensing for crowdsourced content, I would love to hear your thoughts on this! Just reply directly to this email.

2023 Stats and Summary

Now that that is out of the way, back to the year-in-review with some stats and graphs. Over the last year, OldInsuranceMaps.net has received ~5,000 unique visitors. Most importantly, the trendline is clearly going up (spikes correspond to newsletters, georeferencing-events, etc.).

Visitorship is one thing, but what about the georeferencing?? Overall, 4,500 new layers have been georeferenced this year.

Of course, a huge proportion of that is the incredible effort by students and staff at the University of Richmond DSL starting in September (this work continues). We’ll have much more about this effort and what it is achieving in the future. For now, I’ll just shoutout Riley for managing this effort, and to the top-notch georeferencers involved:

wendyle, samyoga, nayers, 10varun17, jattys, JacksonSB, Shelby_m_richards, mekletb, amara017, mirandam, AYAH, and NyKyaSM (sorry if I missed anyone!).

But there have also been a lot of great independent efforts over the last year that I’d like to highlight. For example:

Nolan in Des Moines, IA
Kevin in Macon, GA (and many other nearby towns)
Tod in Salt Lake City, UT
tagifford in Schenectady, NY
Ian in St. Paul, MN
Jason in Essex County, NJ
Pete in Menlo Park, CA

I know there are a handful of other folks who have request maps be added but haven’t gotten a chance to work on them yet, so look out for much more in the coming year!

Georef-a-thons

We held two small events at Second Line Brewing in New Orleans this past summer, especially to support HistoryForge’s use of the site for their New Orleans project (more HistoryForge collaboration coming next year). We created a beautiful mosaic of a 1896 New Orleans volume (and had a few beers too).

Then, in November, Josh and Michelle at Ohio State University held a GIS Day event where they had 30 people participate and georeferenced almost 200 sheets of Columbus maps in 4 hours! I’ll be able to share a nice write-up in the next few months, and they already have another event planned for International Love Data Week.

Thanks for a great year!

Finally, a huge thank you to people this year that helped out, gave advice, or got involved some way or another, in addition to all of the contributors listed above… Jeff Meyers at OpenHistoricalMap; Eve Snyder and Elizabeth Williams at HistoryForge; Rob Nelson and Riley Champine at University of Richmond DSL; and Josh Sadvari at OSU Libraries… to name just a few. The project owes much to you all!

It’s been a great year, and I have no doubt 2024 will see a huge expansion of the usership, engagement, and georeferencing capabilities on the platform.

Happy New Year!

Adam

p.s. I’ve just run out of time and space to describe the tech updates that the past year has seen… if that interests you, see the DevSeed blog post linked above.

Dev Seed: Open Source Spotlight - Old Insurance Maps

Sat, 09 Dec 2023 19:00:00 -0500

Working with Kiri and Sanjay from Development Seed, we put together this post for Dev Seed’s blog: Open Source Spotlight - Old Insurance Maps. This came about because Kiri saw my presentation at FOSS4G Southeast in Nashville last year, where I described how I had reworked OldInsuranceMaps.net to use TiTiler (open source software that Dev Seed created and maintains) for dynamic raster tiling, replacing GeoServer which had been incorporated into the platform from the beginning.

It was very satisfying to put this piece together, and get to talk more about the tech stack that makes OldInsuranceMaps work.

Newsletter: Fall 2023 | Virtual Presentation Tomorrow

Wed, 25 Oct 2023 23:03:00 -0500

Healthy Regions & Policies Lab Speaker Series: Tomorrow!

I will be presenting (virtually) to the Geography & GIScience department at the University of Illinois tomorrow, as part of the Healthy Regions & Policies Lab monthly speaker series. I’m really looking forward to this–it will largely be an introduction and summary of OldInsuranceMaps.net, but I also plan to highlight a bit of the work that the students at University of Richmond have been doing recently. And, anyone can join via Zoom! 12pm Central Time, 40-45 minutes.

More info here: https://healthyregions.org/2023/10/25/october-speaker-series-creating-oldinsurancemaps-net/

HistoryForge: A WMS Integration Success Story

Working with the HistoryForge team we have gotten the mosaicked New Orleans 1895, vol. 1 edition into their web map interface! You can find it in the map overlays at https://sela.historyforge.net/forge. (Also admire the Robinson Atlas and other layers Elizabeth has added while you are there!) Some may recall this edition was the focus of our first georeference-a-thon this past summer. Happy to see it in use outside of OldInsuranceMaps.net! The best thing about this integration is that it spurred some development on the HF platform, so now any maps/mosaics from OldInsuranceMaps.net can be pulled directly in. No need to move files, etc. I have a feeling there will be more HF collaboration in the future!

On the tech side, I’d like to acknowledge Github user mindless-bureaucrat (and of course endless appreciation for Vincent Sarago) who added a WMS endpoint to TiTiler early this year. When they did, I knew it would be useful to us sooner or later, and HistoryForge is a wonderful first use. Now any sheets or mosaics from OldInsuranceMaps.net are available through this standard (get in touch if using layers that way interests you!).

Other News… Constant Activity

Not too many other “big news” items to report at the moment, but everyday 20-30 new layers are georeferenced… Checkout the activity page if you haven’t already, and head to the volume summaries to watch the mosaics grow.

The Spooky Season

Spent a little time last night finding undertakers for you. Enjoy!

New Orleans, La. (1885), Shreveport, La. (1909), Savannah, Ga. (1955), Sacramento, Ca. (1949), and Birmingham, Al. (1951).

Bonus: Artificial Limb Factory in Pittsburgh (1905).

That’s all for now, thanks for reading, and maybe see some of you tomorrow!

Adam

p.s. As always, you can reply directly to this email with questions or thoughts.

HistoryForge: A WMS Integration Success Story

Wed, 25 Oct 2023 18:00:00 -0500

On the tech side, I’d like to acknowledge Github user mindless-bureaucrat who added a WMS endpoint to TiTiler early this year (and of course endless appreciation for TiTiler’s core maintainer, Vincent Sarago). When they did, I knew it would be useful to us sooner or later, and HistoryForge is a wonderful first use. Now any sheets or mosaics from OldInsuranceMaps.net are available through this standard (get in touch if using layers that way interests you!).

Newsletter: July + Aug + 1/2 Sept = Big Updates

Mon, 18 Sep 2023 14:48:00 -0500

Hello everyone, and welcome to a characteristically long-overdue newsletter. Much to report.

Collaboration with University of Richmond DSL and University of Michigan

I’m very excited to announce that beginning this month, a large team of University of Richmond students is now using OldInsuranceMaps.net for a massive georeferencing effort led by Rob Nelson and Riley Champine at the Digital Scholarship Lab. The work will be a foundational component of an NIH grant undertaken through a partnership between the University of Michigan Institute for Social Research, the Richmond DSL, and the National Community Reinvestment Coalition. Here’s the ISR press release for more info.

What this means for OldInsuranceMaps.net is pretty incredible: the University of Michigan is now a funder of the project, and, perhaps more excitingly, the students are already making progress on cities like Birmingham, Miami, Sacramento, and many others.. Also, my new(ish) full-time position at the Healthy Regions & Policies Lab, University of Illinois Urbana-Champaign, will allow a bit of time to be put toward the effort, so my heartflet thanks to everyone that is making this possible!

A shoutout again to Jeff Meyer at OpenHistoricalMap for including me in his presentation at SOTMUS in Richmond–it’s how this new collaboration came about. That presentation video is now on YouTube.

OldInsuranceMaps on Soar

The folks behind Soar got in touch earlier this summer with an interest in getting mosaics from OldInsuranceMaps into their digital atlas, and I’ve pursued this because it is a such a good opportunity to get these maps in front of more people, and perhaps even drive some georeferencing activity as well.

There will be more to say about the Soar in coming weeks, but in the meantime checkout the new OldInsuranceMaps (.net) account where I’ve been trying out some mosaic uploads. Soar offers nice features like the ability to bookmark, comment on, and even embed the maps in other web pages, and they’ve recently released a QGIS plugin, which you can use to search and use any maps in their platform. Many new ways to engage with these maps.

Action in Central Georgia!

A couple of months ago Kevin Haywood, a cartographer from Macon, Georgia got in touch, (donated!), and requested the addition of a few volumes. Well, now you can explore Macon in 1908, Milledgeville (6 years of coverage), and Forsyth in 1920! The work was a hit with a local history groups in the area, which is a category of people I’ve had in mind from the beginning–so happy to see this kind of interest. Thanks Kevin, and to anyone reading from Georgia, check out his trail maps next time you go adventuring!

Georeference-a-thon Update

An exceptionally belated thank you to Eliot, Rick, Hoon, and Nicole who came out to the last georeference-a-thon we had at Second Line Brewing, yes, all the way back in June :/. We continued to work on New Orleans 1896 vol. 1, and since then Elizabeth at HistoryForge has finished it up. It looks great. She and I are working now to integrate that mosaic into the Southeast Louisiana HistoryForge (more news on that to come).

As for future georeference-a-thons, some folks have already approached me about supporting an event for GIS day (November 15th, in case you weren’t aware of this holiday). If an event on that day interests people in the New Orleans area, please get in touch! Maybe we will have simultaneous events in multiple locations…

Performance Improvement and Site Updates

As usual, there are a few developments to the platform itself that I’d like to highlight:

I’ve implemented much better image compression (literally reduced storage needs by 90%) and then rewarped all of the layers. You may notice some “edge artifacts” around the layers at lower zoom levels, before a layer has been trimmed (a very small price to pay).
To support the Richmond work, we’ve upgraded our server instance, and this, combined with me learning about a GDAL setting I should have known about before (oops), speeds the actual background warping process up significantly, just about 5-6 seconds per full page, instead of 20-30. Another great improvement.
Also to support the Richmond work, I’ve added an Activity page so it’s easy to see the latest work sessions at any time.
Finally, a bit of cleaning up the main nav bar and added About and FAQ pages. I know there are probably some FAQs I still have to address there, so if you have suggestions, please get in touch.

That’s all for now! Thanks for your interest, and as always, you can reply directly to this email with questions or feedback.

Adam

p.s. I would love help with putting together this newsletter on a more regular basis (maybe a recent work highlights section??) and generally improving it. Let me know if you have free time and would be interested in helping out.

"Mapping the turn of the Century with OHM and OldInsuranceMaps.net" w

Mon, 10 Jul 2023 18:00:00 -0500

In June I went to Richmond, Va. to present with Jeff Meyer from OpenHistoricalMap at the State of the Map US, an annual meeting for the OpenStreetMap US organization. It was a fantastic conference, and our presentation “Mapping the turn of the Century with OHM and OldInsuranceMaps.net” was really well-received. We demonstrated how people can georeference maps in OIM and then turn around and use them as basemap layers in OHM to digitize historical buildings and other features. The next day we did a workshop as well, where people used this workflow with Sanborn maps of Richmond.

[Video of the presentation here on YouTube: www.youtube.com/watch

Newsletter: Summer 2023

Wed, 14 Jun 2023 13:46:00 -0500

Hello all! Some announcements and recaps, plus a few updates on (subtle but important) improvements to the site.

Before going further though, I’ve scheduled another georeference-a-thon at Second Line Brewing for Tuesday June 27th, 6:30pm-8:30pm! You can RSVP here: https://forms.gle/wTMtoeHR3NwzXN4q8. Also, please fill that form out if 1) you can’t make it on that day but would like to in the future, or 2) you don’t live in New Orleans but would be interested in doing an event like this in your town. I’d love to discuss this idea with anyone interested.

State of the Map US (Open Street Map conference)

I’m recently returned from Richmond, Va., after a great weekend at State of the Map US, an annual regional meeting of the Open Street Map community. I presented with Jeff Meyer of OpenHistoricalMap on Friday, highlighting how you can use georeferenced Sanborn maps from OldInsuranceMaps.net directly in the OHM editor–an extremely easy way to trace old buildings and roads to add them into OHM. A perfect external use of the layers created through this project.

Presentation slides: https://tiny.cc/sotmus23-ac

We also did an OHM map-a-thon on Saturday morning, where folks digitized buildings by using the Richmond 1886 mosaic in OldInsuranceMaps that some of you had already georeferenced (esp. sbuckley730!), and some people started working on Richmond 1895 as well. Great to see some new people work with these old maps :).

Georeference-a-thon Recap & Redux

It seems like a while ago already, but the georeference-a-thon we did in May at Second Line Brewing went really well! About 10 people came, including some fortuitous overlap with a University of New Orleans urban planning department happy hour social. New faces are wonderful to see! We georeferenced about 1/3 of the New Orleans 1896 vol. 1 that we started, and, as you can see from the current state of that volume, people have continued to work on that content so it’s over half done now. We still haven’t setup direct integration of this layer into SELA HistoryForge, but we will get that done eventually.

So, as mentioned above, I’ve scheduled another event with Second Line at the end of this month (they told us multiple times how much they liked this old maps project). Hope to see you there, and maybe we’ll finish this entire volume!

Thanks Elizabeth for taking this photo!

Site Improvements

More reference layers during georeferencing

I’ve (re)introduced the Key Map as a reference layer during georeferencing, click the “layers” button in the bottom right corner to show this option or turn the layer off. Or “r” as a keyboard shortcut to toggle the reference layers.

I’ve also added the option to show all already-georeferenced layers from the volume alongside the one that you are currently georeferencing. This allows you to make very small adjustments to make adjacent layers line up as closely as possible.

Use TiTiler for live georeferencing preview layer

I recently swapped out MapServer for TiTiler to generate the live preview during georeferencing. I’ve used MapServer for this one small functionality since the beginning of the project because it was easier to use with VRTs than GeoServer (and a fun excuse to learn a little about it), but now that TiTiler handles tile generation everywhere else (and natively serves VRTs), this was the natural next step. Happy to have it squared away.

Set documents as “non-maps”

I’ve finally addressed, at least in part, the very first ticket in the repo, a request for a way to mark particular documents as “not-georeferenceable.” Now, once a document is prepared, you can mark it as a non-map, moving it into a separate category in the volume summary page. This is necessary for images like the title page and text index, and allows for a more accurate georeferencing completeness percentage to be calculated across the volume.

Improving management of other layer classifications

Also on the topic of content management, I’ve added a few more categories for layer classification within a volume. To date, we’ve just had Main Content and Key Map, but as we found a long time ago in Shreveport, some volumes include a “Map of Congested District,” or, more recently in Columbus, a “General Index of Volumes.” This content will overlap other content from the same volume, so it must be set apart so it can (eventually) be placed into separate layers in the Mosaic Preview map or main viewer… tiny steps in the ever-churning, slow move toward a more generic system.

That’s all for now! If you recently signed up and are getting this newsletter for the first time, you can read my past sporadic missives in the archive.

Adam

OldInsuranceMaps News

Georeference-a-thons! HistoryForge (New Orleans), UMD, and UIUC

Upcoming Georeferencing Events in New Orleans

Mapping Historical Duluth: A Crazy Long-Term Project You Can Contribute To

Engineering Open House at UIUC

Code4Lib 2026 - Video links and other notes

Code4Lib 2026

Newsletter: Winter (pt 2)

New newsletter platform

Getting out and about

Mapping USA: Video now on YouTube

This week (tomorrow!): Code4Lib

Hacker News post

RSS, anyone??

Upcoming: Mapping USA and Code4Lib

Mapping USA (January 31)

Code4Lib (March 2-5)

Newsletter: Winter 2025

2026 and what it will look like

Who uses OldInsuranceMaps.net?

Improvements to the “multimask” interface

Is that… a leaderboard??

Faster tile loading

Community notes

Georeference-a-thons in New Orleans

MapRVA presents: Yesterdays

(Re)Introducing the MultiMask Interface

Make me a clean mosaic

Cropping vs. splitting & trimming

Trimming each layer by itself is slow

Putting it all together: Multimask

Snapping as a core value

Masks make a fabric

What is that street name?

Using colors for quality control

Some final thoughts

Newsletter: Fall 2025 - Upcoming Events

Georeference-a-thons in New Orleans

Front-end Party!

That’s all for now!

Using GDAL's VRTs for Georeferencing, from "A look inside OldInsuranceMaps.net"

Newsletter: Summer 2025

Online presentation for I-GUIDE VCO series, tomorrow!

Results of a past georeference-a-thon

Website content reshuffle and new Blog

And a final tech note…

Implementing S3 Object Storage

What is S3 Object Storage?

Implementing a new storage backend

Code compatibility

Syncing the content

The result

Newsletter: 2024 in Review + new features!

2024 Stats and Summary

Georeference-a-thons

New features

Looking ahead

Thank you!

Newsletter: GIS Day Events | NACIS | Data Agreement

Georeference-a-thons of Future

UIUC - Healthy Regions & Policies Lab

University of Chicago Libraries

Morgan State University - The Black Butterfly Project

The Ohio State University Libraries

Georeference-a-thons of Present

Georeference-a-thons of Past

Presentation(s) at NACIS in October

Finally: Data Agreement

"Handling Complex Content within Georeferenced Historical Atlases"

Newsletter: Fall 2024

Upcoming Georeference-a-thons!

CC licensing update

Other Recent Work…

Newsletter: Spring and Mid-Summer Updates 2024

We have a new Community Forum!

Recent publications about OldInsuranceMaps.net

Stats!

Other new things

"Piloting a Sanborn Map Georef-a-thon for GIS Day 2023"

Newsletter: 2023 Year in Review