Manual – Points and Links
Place New Points
To place a new point in the old or the new map select the Set New Point button in the toolbar and click in the map. When placing a new point, all previously existing points are deselected and the new point selected. Selected points are displayed in red.
Copy and Paste Points
You can copy selected points with Edit - Copy and paste the points in a different document with Edit - Paste.
Undo and Redo
All actions altering control points can be undone and redone. Use Edit - Undo... and Edit - Redo...
Linked points are essential for the computation of statistical values (e.g. scale and rotation) and the different visualizations. Only linked points are used for the computation, unlinked points are ignored. At least five pairs of linked points are needed to execute a computation. Generally speaking, the more linked pairs of points you have, the more reliable the results of the computation will be (such as the estimated scale and rotation of the old map).
To link two points, first select a point in the old map and one in the new map using the Select Points tool. Note that after placing a new point in a map, the point is automatically selected. Then press the Link Points button in the lower part of the window. Finally, you will be asked to assign a name to the new pair of linked points. The name of the newly created pair of linked points and its coordinates are displayed below the Link Points button.
Rename Linked Points
To rename a pair of linked points, first select the two points by clicking on one of them. Note that clicking on a linked point automatically selects its paired point in the other map. Then press the Rename button in the lower part of the window, and type the new name in the dialog.
Two linked points can be found by their name. Choose Points - Find Link... and type the name of the searched link. If MapAnalyst finds a pair of linked points with the specified name, it will select the two points.
Import and Export of Points and Links
ASCII files with point data can be imported and exported. MapAnalyst offers three different options for importing and exporting points:
(1) Import or export all points of the old map.
(2) Import or export all points of the new map.
(3) Import or export all linked points only. This will handle points from the old and new map together.
Choose File – Import Points or File – Export Points, and then For Old Map (1) or For New Map (2) or Linked Points for Old and New Map (3).
Points in the old and new map use coordinate systems with the Y-axis pointing upwards.
When importing or exporting points for the old or the new map, MapAnalyst requires the following ASCII format:
|Column 1||Column 2||Column 3|
MapAnalyst will ask for the units of the coordinates. Available options are:
Geographic longitude / latitude values are available only when exporting points placed on the OpenStreetMap reference map. Geographic coordinates are in decimal degrees using the standard web map datum with a spherical radius 6378137 m.
Pixel coordinates are only available after a map image has been loaded (old or new). Pixel coordinates are not available when OpenStreetMap is used as reference map. Note that for the old map, the origin for all coordinates is the lower left corner of the map. Other software, such as the ArcGIS Georeferencing tool, may use the upper left corner as origin when specifying coordinates in pixels. In such cases, uses spreadsheet software to convert the pixel coordinates.
MapAnalyst can also export points to the ESRI Shape file format. Importing points in ESRI Shape format is not currently supported.
When importing or exporting linked points for the old and the new map, MapAnalyst uses the following format:
|Column 1||Column 2||Column 3||Column 4||Column 5|
Important: When importing linked points for the old and new map together, all coordinates must be in meters. This is usually the case for the reference map, except if coordinates are in “geographic” coordinates (i.e. degrees of longitude and latitude). In this case, split your data into two files, one with points for the old map and one with points for the new reference map. Then import the points separately for the old and the new map. Use spreadsheet software to convert the coordinates to meters. Example: If your old map measures 600 x 600 millimeters, your coordinates must be in the range of 0 to 0.6.
Points in ASCII text files must separated by a comma. If you edit your point list in spreadsheet software like Microsoft Excel, it is recommended that you export the list as CSV file (Comma Separated Values). Note that some versions of Excel use semicolons instead of comas to separate values. In this case, use an ASCII text editor to replace semicolons with comas.
Important: Values separated by tabs, semicolons or other characters are not supported.
Placing Points from a List
Instead of placing the points in the new reference map by clicking with the mouse, you can alternatively extract your points directly from a text file. The file must contain the names, X-coordinates, and y-coordinates for the new map, using the format above. Choose Points - Place Point from Coordinate List. MapAnalyst will ask you for the list of names (note that you only have to do this the first time). Then type the name of the place to add to the new map.
List of Linked Points
MapAnalyst can list the names and coordinates of all linked points with the command Points - Show List of Linked Points.
Points Color Options
You can adapt the point symbol using Points - Point Symbol. The color of the linked and unlinked points can be selected separately using Points - Color of Linked Points and Color of Unlinked Points.