A New York Public Library website

As of April 2021, Mapwarper will no longer be updated by NYPL, and will soon be archived. This means all embedded views utilizing Mapwarper will no longer work once the site is archived. However, all contributions and data will be retained by the Library for future use and research.

Thank you for your interest and use of the tool. You can find our source code and documentation for Mapwarper and other NYPL projects here.

NYPL Map Warper

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How to use this tool

The NYPL Map Warper is a tool for digitally aligning ("rectifying") historical maps from the NYPL's collections to match today's precise maps. Visitors can browse already rectified maps or assist the NYPL by aligning a map. Play the video above to tour the site and learn how to rectify a map yourself.

Everyone is welcome to participate!

Recipient of the 2012
Cutting Edge Technology in
Library Services Award from
the Office of Information Policy
of the American Library
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Most Recently Rectified Maps

Map Title Year Last modified Status
?t=t&id=433950
from New York harbor (In 1 layer) Depicts: 1845
1845 27 minutes ago. 10 control points.
?t=t&id=1637907
from Height district map / City of New York, Board of Estimate and Apportionment. (In 1 layer) Depicts: 1916
1916 about 22 hours ago. 9 control points.
?t=t&id=1637955
from Area district map / City of New York, Board of Estimate and Apportionment. (In 1 layer) Depicts: 1916
1916 2 days ago. 6 control points.
There are no known US copyright restrictions in maps available through Map Warper.
NYPL is distributing these images under a Creative Commons CC0 1.0 Universal Public Domain Dedication.
For more information, see the Export tab for a map.