Run v2.0

Georeferencing for the Library of Congress's Sanborn Maps Collection, made automatically by mapsnap: each placed sheet is a IIIF Georeference Annotation you can open in Allmaps or any viewer that reads them.

30,611volumes published, of 35,101 in the collection

343,403sheets placed, of 425,593 (81%)

379,081georeferenced images (a split sheet is several)

11,864key maps

7,820cities and towns

1867–1963years

Try one

New York, Bronx, Manhattan, New York, vol. 1, 1923 opens in the Allmaps viewer: 36 georeferenced sheets over today's map, drawn from Chronoscope's copies of the scans. The file behind it is https://data.mapsnap.org/runs/v2.0/iiif/chronoscope/sanborn06116_046.main.iiif.json.

Find a volume

Search every volume in the run by town, state, year or Library of Congress id. A title opens the volume's page; View opens its placed sheets over today's map in Allmaps, and JSON is the IIIF file behind them.

Images: Chronoscope loc.gov

Download

mapsnap-v2.0-loc.zip	Every IIIF file, pointing at loc.gov, with items.tsv and README.txt	132 MB
mapsnap-v2.0-chronoscope.zip	Every IIIF file, pointing at Chronoscope, with items.tsv and README.txt	127 MB
items.tsv	One row per volume, published or not	6 MB

States

State	Volumes published	of	Sheets placed	of	%
Alabama	389	452	4,052	5,549	73%
Alaska	13	27	34	92	37%
Arizona	142	197	1,399	1,916	73%
Arkansas	482	572	3,570	4,478	80%
California	1,324	1,715	23,878	29,127	82%
Colorado	458	519	3,132	4,013	78%
Connecticut	375	461	5,466	7,123	77%
Delaware	90	95	492	613	80%
District of Columbia	8	9	365	657	56%
Florida	375	429	3,900	5,162	76%
Georgia	521	592	4,013	5,285	76%
Hawaii	21	39	986	1,307	75%
Idaho	296	395	1,819	2,414	75%
Illinois	1,767	1,883	22,899	26,267	87%
Indiana	1,199	1,261	13,040	14,904	87%
Iowa	1,023	1,178	6,819	8,720	78%
Kansas	876	964	5,786	6,873	84%
Kentucky	465	569	4,615	6,086	76%
Louisiana	385	429	5,069	6,048	84%
Maine	425	594	2,751	3,797	72%
Maryland	287	321	5,705	6,883	83%
Massachusetts	956	1,012	15,966	19,050	84%
Michigan	1,299	1,370	13,216	16,335	81%
Minnesota	660	854	7,019	9,739	72%
Mississippi	393	455	2,343	3,059	77%
Missouri	1,078	1,150	9,507	10,830	88%
Montana	350	481	2,686	3,430	78%
Nebraska	408	524	2,453	3,262	75%
Nevada	70	81	499	611	82%
New Hampshire	281	358	2,180	2,879	76%
New Jersey	829	874	15,163	18,406	82%
New Mexico	129	153	1,088	1,379	79%
New York	2,188	2,517	31,428	39,700	79%
North Carolina	504	553	4,910	6,488	76%
North Dakota	176	224	1,053	1,447	73%
Ohio	1,698	1,749	24,978	30,036	83%
Oklahoma	971	1,191	5,710	7,182	80%
Oregon	445	582	3,540	4,806	74%
Pennsylvania	1,906	2,025	22,572	27,231	83%
Rhode Island	117	129	3,423	4,122	83%
South Carolina	331	376	2,460	3,196	77%
South Dakota	374	425	1,317	1,672	79%
Tennessee	463	542	7,827	9,612	81%
Texas	1,419	1,597	15,689	18,841	83%
Utah	52	164	1,352	2,511	54%
Vermont	268	321	1,559	2,232	70%
Virginia	446	489	5,864	7,755	76%
Washington	646	806	7,831	9,504	82%
West Virginia	276	295	2,666	3,485	76%
Wisconsin	859	977	6,615	8,543	77%
Wyoming	98	126	699	936	75%

The files

Each published volume has a IIIF AnnotationPage of its main content, <item>.main.iiif.json, and of its key map when one was placed, <item>.keymap.iiif.json. Every file comes in two versions that differ only in where the scans are fetched from:

https://data.mapsnap.org/runs/v2.0/iiif/loc/ points at the Library of Congress's own image servers, the original scans.
https://data.mapsnap.org/runs/v2.0/iiif/chronoscope/ points at Chronoscope's copies of the same scans at a quarter of their size, which load much faster and are kinder to loc.gov.

Each file's id is its own URL. Every image is a georeference annotation: control points, a transformation, and a clip outline for the part of the sheet that is map.

Limitations

mapsnap can't place every page, and not every page it places is accurate: a sheet can land on the wrong block, or in the wrong town. If you find a volume that's wrong, please report it on GitHub.

If a Chronoscope Allmaps link doesn't load on mobile, try the loc.gov link or a desktop browser.

OldInsuranceMaps.net

mapsnap was built with data from OldInsuranceMaps.net, where volunteers have georeferenced Sanborn maps by hand; their work is what mapsnap was developed and measured against. If a volume you want isn't listed here, or is missing pages, look for it on OldInsuranceMaps.net, or georeference it by hand there.

items.tsv

`item`	The Library of Congress item id; its page is https://www.loc.gov/item/<item>/.
`city, state, year, date`	The town, its postal code, and the volume's year and catalog date.
`volume`	The volume number, where the catalog gives one.
`title`	The catalog title.
`sheets`	Map sheets in the volume. A skeleton sheet (pNs) and its full-color sheet (pN) count once, since at most one of them is published; title and index pages are left out.
`scans`	Every image the Library of Congress catalogs for the volume.
`images`	Images the run split the sheets into (split sheets become several).
`placed`	Images the run georeferenced.
`published`	Images published: those placed, less the ones dropped below.
`sheets_placed`	Sheets with at least one published image.
`dropped_over_6km`	Images dropped because their sheet would span over 6 km of ground.
`dropped_over_5km_from_location`	Images dropped because, in a volume of 10 sheets or fewer, they sit over 5 km from the catalog's location for the town.
`dropped_keymap`	Images dropped because they are the volume's key map, which is published in its own file.
`status`	published, published: key map only, no page placed, or withheld and why.
`main, keymap`	The volume's IIIF file names, under iiif/loc/ and iiif/chronoscope/; blank if none.

License

The georeferencing annotations are © OpenStreetMap contributors and mapsnap, available under the Open Database License 1.0: their control points are OpenStreetMap positions. Individual contents are under the Database Contents License. The sheet images are the Library of Congress's Sanborn Maps Collection.

Report issues on GitHub. See the FAQ. For other questions, contact Dan or join the #mapsnap channel on OSMUS Slack.