Difference

Create a coverage showing the differences in attribute values between two raster surfaces in order to determine the amount of deformation that has taken place.

The Coverage Difference command is useful for comparing changes to an area over time. A difference coverage can be used to monitor these changes by comparing two surfaces for the same area that were created at different times. The coverage difference relative to a model or two raster surfaces of surveys from different epochs can be determined.

To determine the deformation, a new coverage is calculated based on the differences in distance from a plane between the reference model and the selected coverage. This coverage is then coloured according to risk classifications defined in a colour range file.

To use this tool, you must select two files (Input A and Input B) that cover part or all of the same area, or a single file containing multiple bands for a comparison. These files can be any combination of the supported coverage types (a raster surface and a reference model, a raster surface and a point cloud, and so on).

Input B will be subtracted from Input A to calculate the difference. A new coverage is generated for the difference; the new coverage will be the same type as Input A. For example, if Input A is a point cloud, the new coverage will be a point cloud.

See Difference Coverage for information on this tool.