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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
From Atlas 44. Vol. B, 1897. (In 4 layers) Depicts: 1897
1897 22 minutes ago. Unrectified.
From A general map of the empire of Germany, Holland, the Netherlands, Switzerland, the Grisons, Italy, Sicily, Corsica, and Sardinia (In 2 layers)
about 1 hour ago. 13 control points.
from Philadelphia (In 6 layers) Depicts: 1850
1850 about 16 hours ago. 5 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.