Shortest Path


Another form of surface analysis that Maptitude can perform, is that of Shortest Path determination. This is not a route finding calculation, rather it finds the shortest path across a surface, taking into account gradients.

Shortest paths can only be calculated with gridded surfaces. If you have a TIN (Triangulated Irregular Network) then you will need to create a gridded layer of this data using the Grid button (3×3 grid button, second from the right), on the Surface Analysis Toolbox.

With the gridded surface layer selected as the working layer, select Terrain Shortest Path on the Tools->Surface Analysis sub-menu. This will display the Terrain Shortest Path dialog box:

Terrain Shortest Path dialog box

Press the Origin button (green flag), and click on the path’s start location on the map. Maptitude will mark this location with an ‘S’ on a dark blue square. Press the Destination button (chequered flag), and click on the path’s destination location. This will be drawn with an ‘E’ on an orange square. Press the Find Terrain Shortest Path button (red line with magnifying glass) to calculate the shortest path. This will be drawn on the map with a red line.

There are two drop down boxes that control how the path is calculated. Accuracy determines the accuracy of the path, balancing the processing time verses the route detail. High indicates a more detailed route at the expense of greater processing time. Penalty determines how much of a penalty should be applied to gradients. Low indicates that the distance is more important than elevation changes, resulting in paths that are shorter and hillier. High indicates that changes in elevation are more important than distances, resulting in paths that are longer but flatter.

Here is an example in the Snowdonia dataset with Normal accuracy and High penalty:

Sample terrain path drawn on the Snowdonia terrain data

Notice that the path does not form a straight line. Instead, it heads to the north into the main valley (green), and then heads up the center of the main valley to the destination.

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