A raster layer must be loaded into ArcMap in order to use this tool. The raster layers in ArcMap are
listed in the Numerical or Categorical boxes as follows: all floating point rasters are only
listed in the Numerical box, all integer rasters are listed in both the Categorical and Numerical boxes.
Select the rasters you wish to process by checking the box next to the raster name. Do not select
the same raster in both the numerical and categorical boxes (not only is this not appropriate, it will
also cause the program to fail).
Input raster data type.
There are about a dozen raster data types that can be used to represent raster data. Of these, there
are only four that can be represented as variables in Visual Basic. If you run this tool and receive
an error message (an “automation error”), then you must convert the type of the input raster dataset.
Use the Raster Pixel Type Conversion Tool to do this (refer to that tool for more information).
Scales / Radii.
This program processes multiple scales (i.e. multiple roving window sizes) simultaneously. Type in a
comma delimited list of roving window radii into the text box (e.g. 500, 1000, 2000, 3000). Note that
although you can specify as many scales as you wish, that you must ensure you have enough disk space
to support this number of output rasters (remember that an entire set of output rasters is created
for each input grid, at each scale – this can be many gigabytes of data).
Process edge cells.
Roving window analyses are complicated by the fact that for cells near the edge of the raster (i.e.
at a distance less than the radius of the roving window) the sample size of cells within that window
is less than the sample size for a window in the middle of the raster (i.e. sample size diminishes
the closer to the edge you get). Depending on your application/analysis, it may be most appropriate
not to process these cells in the roving window analysis. This is a statistical bias issue and
you must make your own informed decision. On the other hand, for large window sizes, this may
eliminate a large portion of your study area. You therefore have the option to process edge cells
or not. Note that processing the edge cells will add considerably to processing time.
Numerical grid outputs.
This tool is fast because of the coding mechanisms used (what I call the “slider approach”).
Unfortunately, this approach prohibits the calculation of some metrics that are commonly
calculated for numerical rasters, namely: minimum, maximum, range and standard deviation. What
can be calculated is the sum, mean, and count. If you need the other metrics, you sould use
the Neighbourhood Analysis tools in Spatial Analyst.
Because of the number of output layers created by this program, the only output information
you are asked to provide is the name of an empty folder. As the naming conventions in this
program are automatic, it is very important that the folder is empty (to prevent any naming