Geomorphic Change Detection Software


The Options dialog includes tabs for customizing different aspects of the GCD software. All options are user-specific, meaning that any changes are saved for the current user only.

Survey Types

Survey types can be customized to represent different topographic survey methods. Each survey type is associated with a default uncertainty method. These defaults are used during the calculation of multi-method error surfaces. If the regular mask used to generate the error surface contains mask values that match one of the survey types in the list then the corresponding uncertainty value is used as the default uncertainty value. Users can override this value and the default is simply intended as the initial value.

Survey Types

This video shows you how to modify and/or add new survey types.


The symbology tab allow users to control display properties when layers are added to ArcMap. This tab only affects the GCD AddIn and serves no purpose for the GCD Standalone.

  • The Auto Apply Transparency set of controls allow users to control whether the selected surfaces are added to ArcMap with transparency applied. The transparency value specified is in percent where 0% represents solid and 100% represents totally transparent.
  • The Comparative Symbology set of controls applies to specific types of rasters and allows for fixed range symbology to be used where applicable. With these checkboxes unchecked the corresponding raster types are added to ArcMap with color ramps scaled to the data range of the corresponding raster data.
  • Checking the Manual DoD symbology range checkbox applies a fixed color ramp range to all DoD rasters as they are add to ArcMap. With the checkbox checked the value in the adjacent numeric control is used to fix the color ramp. The value is in the vertical units of the current GCD project. Unchecking the checkbox results in DoD raster color ramps scaling to the entire range of each individual DoD raster.


Graphs Tab

The Graphs tab simply controls the output resolution and dimensions (in pixels) of the output *.png graphic image files that are automatically produced by GCD when generating a change detection analysis. The default is for a square graph at 600 x 600 pixels. The graphs currently exported by GCD include the volumetric and areal elevation change distributions associated with both the Change Detection and Budget Segregation panels.

NOTE: All graphs produced in GCD can also be exported manually from their respective panels/dialogs (with a right click) and that all the data required to produce these graphs automatically is also exported to the corresponding analysis output folder.

The colors section of this tab controls the default colors used for the change detection graphics generated by the software. The values specified on this form are used by default but can be overridden in the change detection properties dialog. Clicking the reset button reverts to the system default red for surface lowering and blue for surface raising.

The font specified is used as the default for all change detection graphics. The font specified on this form is used by default but can be overridden in the change detection results properties dialog. Click the settings button to pick a different font.



Check the box beside a particular type of GCD raster to have pyramids produced automatically whenever GCD generates a raster of the corresponding type. Note that pyramids are only beneficial to the display of rasters and have no affect on the actual raster values themselves. Generating pyramids does slow GCD slightly and also the pyramid files require additional file storage which can be a consideration if you intend to share your GCD project with others.