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Historical Maps: Making Map Overlays

This Historical Maps guide contains information on how to find maps of various regions and periods throughout history and introduces you to tools to help you create visual representations of historical data using those maps.

Warping a Map to Fit

Because maps can be created in a number of different projections and varying degrees of accuracy, the landmasses, countries, bodies of water, roads etc. may not exactly match up between any two maps. In order to counteract this problem, a number of tools exist that allow you to warp (also known as rectify or georeference) a map, so that it will fit on a Google Map or another mapping applications's interface. The resulting warped map should then be easier to work on using that application.

Application Description Benefits Drawbacks Tutorial
Google Earth Overlays

Putting a historical maps on Google Earth is very simple. It is simply laying the  map image over a section of the globe on Google Earth, then resizing the map image so that it lines up with the features on the globe.

Unlike the other tools in this section there is no stretching involved. Because of this, it is very difficult to get a perfect match unless you're mapping a small area and the map is drawn to scale.

Learning curve:

Incredibly simple to use, but hard to get precision.

Quick

Requires Google Earth Software

Cannot warp maps, can only resize and rotate maps

Usually not very accurate

Google Earth Tutorial 
WorldMap WARP

WorldMap WARP is an online tool to rectify an uploaded map so that it may fit exactly(or more closely) on a modern precise map, such as a Google map. While rectifying maps, WorldMap WARP also geo-references the uploaded map on an online modern map, so that physical landmarks(coasts, streets, geological features, etc.) will lay ontop of each other.

Similar in design to NYPL Map Warper and Map Warper, however this tool seems to be no longer maintained. It is at its best when you're just trying to warp a map to an area so that you can download the rectified PNG or TIFF or store it for later use, or if you want to use the the warped map's "tiles base URL" in other tools. You can use its "Tiles base URL",  but you need to add curly brackets(i.e. { }) around the "x", "y", and "z".

Basically this is the same tool as Map Warper except it is less maintained and the maps can be made private.

Learning curve:

Warping a map is fairly intuitive. Other features require more guidance (exporting the map is not very intuitive), and the fact that the tool appears to be no longer maintained makes some the tool slightly harder to work with.

Any map (in XYZ format) can be warped

Can add metadata to the maps

Can be set to public or private

Can be done on any computer/web based;  Can export an image of the rectified map as a PNG or a TIFF,  as a KML file, or a WMS URL

Keeps a record of the edits made to the map

Can be edited by multiple people for collaborative purposes

Not always the most accurate

The cropping section of the site no longer appears to work

WorldMap WARP Tutorial 
Map Warper 

Map Warper is an online tool to rectify an uploaded map so that it may fit exactly(or more closely) on a modern precise map, such as a Google map. While rectifying maps, Map Warper also geo-references the uploaded map on an online modern map, so that physical landmarks(coasts, streets, geological features, etc.) will lay ontop of each other.

 

Similar in design to WorldMap WARP and NYPL Map Warper. It is at its best when you have a map that cannot be warped onNYPL Map Warper or David Rumsey Georeferencer and you want to collaborate with others or work from any computer when rectifying the map, or if you want to use the the warped map's "tiles base URL" in other tools.

Basically this is the same tool as Harvard's WorldMap WARP except it is more maintained and the maps cannot be made private.

Learning curve:

Warping a map is fairly intuitive. Other features require more guidance(exporting the map is not very intuitive).

Any map (in XYZ format) can be warped

Can add metadata to the maps

Can be done on any computer/web based; Can export an image of the rectified map as a PNG or a TIFF, as a KML file, or a WMS URL. Keeps a record of the edits made to the map

Can be edited by multiple people for collaborative purposes

Not always the most accurate

Edits can only be set to public, so everyone can see the edits

Map Warper Tutorial 
NYPL Map Warper

NYPL Map Warper is an online tool to rectify a map so that it may fit exactly(or more closely) on a modern precise map, such as a Google map. While rectifying maps, NYPL Map Warper also geo-references the chosen map on an online modern map, so that physical landmarks(coasts, streets, geological features, etc.) will lay ontop of each other.

 

Similar in design to WorldMap WARP and Map Warper. It is at its best when you've found a map from the NYPL Digital Collections and you want to collaborate with others or work from any computer when rectifying the map, or if you want to use the the warped map's "tiles base URL" in other tools.

Basically this is the same tool as  WorldMap WARP and Map Warper except it will only work for maps from NYPL Digital Collections.

Learning curve:

Warping a map is fairly intuitive. Other features require more guidance(exporting the map is not very intuitive).

Can add metadata to the maps

Can be done on any computer/web based;  Can export an image of the rectified map as a PNG or a TIFF,  as a KML file, or a WMS URL

Keeps a record of the edits made to the map

Can be edited by multiple people for collaborative purposes

Can crop edges of the map so that only geographic information is warped

Can only warp select maps from the NYPL Digital Collections

Not always the most accurate

Edits can only be set to public, so everyone can see the edits

NYPL Map Warper 
David Rumsey Georeferencer

The David Rumsey Georeferencer is an is an online tool to rectify a map so that it may fit exactly(or more closely) on a modern precise map, such as a Google map. While rectifying maps, David Rumsey Georeferencer also geo-references the chosen map on an online modern map, so that physical landmarks(coasts, streets, geological features, etc.) will lay ontop of each other.

It is at its best when you've found a map in the David Rumsey Map Collection and you want to collaborate with others or work from any computer when rectifying the map.

Learning curve:

Sometimes it can be frustrating to find a map on David Rumsey that is available to be georeferenced. Otherwise the tool is fairly intuitive, and there is a guide to explain the features that aren't.

Simple and easy to use design

Easily see two warped maps layered on top of each other

Fast warping

Can only warp select maps from the David Rumsey Map Collection

Edits can only be set to public, so everyone can see the edits

David Rumsey Georeferencer Tutorial 
Map Tiler 

Map Tiler is a tool to rectifiy a map so that it may fit exactly(or more closely) on a modern precise map, such as a Google map. arper also geo-references the selected map on an online modern map, so that physical landmarks(coasts, streets, geological features, etc.) will lay ontop of each other.

This tool unlike most of the other tools in the page is not an online tool. It uses online maps to rectify your map, but you must have your own map as a file on the computer you're using. Map Tiler is at its best when you have a map on your computer and you want it to predict where the points will be or you want to get very technical.

Learning curve: 

Rectifying the map is simple, especially since it predicts points.

Exporting the map and then hosting so that you can share it is complicated. The Map Tiler website offers a How-to section, which should help with most features.

Automatically predicts points you select with increasing accuracy, after you've added 2 points.

Has an associated iOS and Android app that allows you to view the rectified maps.

Map Tiler software must be downloaded and installed to use

Associated iOS/Android app is not free.

Once a map has been rectified, it cannot be re-rectified; you must start the project again.

Leaves watermarks on the map, in the basic version

Map Tiler Tutorial 

 

Examples

Digital Harlem

Digital Harrisburg

  • Mapping Gothic France: Mapping Gothic France is a database of images, texts, charts, and historical maps related to Gothic architecture and France in the 12th and 13th centuries created by Stephen Murray of Columbia University and Andrew Tallon of Vassar College. The maps have been warped and overlayed on a basemap. Markers that represent buildings with Gothic architecture have been placed on the maps.

Mapping Gothic France

  • PhilaPlace: Philaplace is a site that chronicles Philadelphia Neighborhoods and was developed by Joan Saverino for the Historical Society of Pennsylvania. The site uses a number of warped maps on Google Maps to show the relationship between photos, events, stories, and where they occurred.

PhilaPlace

 

 

Live Example of Map Tiler

Created using Map Tiler

Taylor, A. Merritt. Tentative Location of Future Rapid Transit Lines. In: Taylor, A. Merritt. Report of transit commissioner, city of Philadelphia, July, 1913 Vol. 2. Philadelphia: City of Philadelphia, 1913, Map No. 45.