ii. Bootstrap Roughness Modeler

The Bootstrap Roughness Modeler Tool is located under the Analysis menu and further the Roughness Analysis menu:

A video tutorial for how to use the Bootstrap Roughness Modeler can be seen below:

GCD - Bootstrap Roughness Modeler

When the Bootstrap Roughness Modeler is run, the following dialog appears:


The inputs for this tool are:
  • Input Survey Points
    • point feature class of the points used to create the Digital elevation model (DEM) used as input below.
  • Survey Extent
    • Polygon feature class representing the extent of the survey.
  • Channel Extent (optional)
    • Polygon feature class representing areas not to be included in the bootstrapping. For example if a channel unit polygon feature class is used as input then the bootstrap will only be performed using points that exist outside of the channel unit feature class.
  • DEM
    • Digital elevation model (DEM) that was created from the input survey points.
  • Convert to millimeters (optional)
    • if this check box is selected then the output results will be in millimeters
  • Vertical units of DEM (optional, only enabled if Convert to millimeters is checked)
    • grain size metrics are generally reported in millimeters so a conversion based on this value is performed to get values in millimeters.
  • Number of Iterations
    • controls the number of times that points should be randomly sampled and differenced from the DEM.
  • Percent of data to keep as subset each iteration
    • controls the percent of data that should be kept during each iteration to make a DEM to compare with the DEM provided above.


The outputs for the tool are:
  • Output Raster Path
    • path to save the output bootstrap roughness raster to. The output raster is comprised of the mean delta Z between each iteration of sub-setting points and the original DEM.