Manual – Toolbar

The toolbar is located in the upper left corner of the window and contains a series of buttons. To see the names of the tools, hold your mouse cursor over the buttons without moving it.

Compute Button

Pressing the Compute button calculates the scale and the rotation of the old map, and updates the different visualizations. The computation may take a few seconds. The computation time depends on the number of linked points, the chosen transformation, the settings for the different visualizations, and the speed of your computer.

The points of the old map are transformed on the points of the new reference map using the currently selected transformation. For further informations see the page about Transformations.

Edit Points

The toolbar offers three tools to select, place and move points. The tools can be activated with the buttons Select Points, Set New Point and Move Selected Point (hold your mouse cursor over the buttons to see their names). For further informations about editing points see Points and Links.

Zooming and Panning

Change the current zoom factor of the map using the Zoom In or the Zoom Out button in the toolbar. To display the whole content of both maps, press the Show All button.

Select the Pan button to move the currently visible area of the map. To change the visible area, click on the map and drag the cursor while keeping the mouse button down.


You can measure the distance and the angle between two points. Select the tool Measure Distance and Angle, then click on the start point and drag the mouse to the end point. The according distance and angle are displayed to the right of the toolbar.


To draw a polygon press the button Draw Polygons. Construct a polygon by clicking in the map. Double-click to close the polygon. The polygon will not be closed when you select another tool. A closed polygon can be used to delimit a distortion grid (see Distortion Grid for more information).

Information for the Mouse Location

The following information on the current mouse location is displayed to the right of the tool buttons:
1. Position (horizontal x and vertical y coordinates).
2. Estimation of the local scale and rotation (see Isolines for more information about local scale and rotation).
3. The name of a point (when the mouse is over a point).

Select the unit for displaying coordinates in the toolbar with View > Old Map Display Coordinate Unit. Available units are centimetre, metre, inch, and pixel.