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David Rumsey

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Map border margin
Visible Clipped with cutline
Scaled s Similarity p Affine q Polynomial t TPS

Add a custom map service

+ -
🔒 🔓 0 Use Alt+Shift+drag to rotate manually
+ -
< Map 
Image >
Now you edit location in the old map
Now you edit location in the modern map
Hold/Release SHIFT key to switch
It looks like this map is finished Save Next
+ Secondary map
  • Coordinates
  • Projection
  • Transformation
X Y Error [px]


Transformation is a process when the image is moved to a new position which is based on adding of control points. The map has to be sometimes deformed. Here you can set a default value for transformation. This is used as a default transformation for displaying of a map, 3D globe and Web map services (WMTS, TileJSON and XYZ).

Default transformation:
The cutlines are not allowed to overlap! Fix this by dragging the cutline nodes or removing them using the delete key.
Please, place a few more points.
There are already too many points on this map. Please improve the existing points rather than adding more.

Welcome to Georeferencer

Here you assign a location to a scan and overlay it on top of a modern map. Help us to give these maps a new life! It is a simple process.

Find the same place - side by side

Your target is to find the same place on the modern map and on the scan. Click on both of them. More points improve the precision. Quality matters.

After few points try Overlay & Clip

Use the Overlay to preview and adjust the position of the map overlay interactively. The Clip mode can remove a border from the map. Additional functions of the tool are explained under help.

Type a place name and hit ENTER or choose from the suggested alternatives.
Switch to one of the offered basemaps or add your own map service. We are supporting WMTS or TileJSON.
Synchronize drag and zoom on both maps.
Change rotation of the old map.

Switching between the scan and the modern map.

Use the SHIFT key to toggle between the scan and the modern map.

Editing in Overlay mode

If you see a place on an incorrect position, click on it and choose where it should appear. The map overlay is immediately recalculated.

Accuracy & coordinates

Get coordinates and accuracy for individual points in selected transformation and map projection. It helps you to identify wrongly placed points

Clip the map borders

Drag the circle nodes around the area to create a cutline.

Detail makes a difference

Click on the point once to get in the detailed view for higher accuracy positioning. Press DELETE key to remove the point.

Secondary maps

More maps on the scan? Click on the "Secondary map" button to separate it from others.