This tool can be used to calculate the difference between the elevation of each grid cell and the mean elevation of the centering local neighbourhood. This is similar to what a high-pass filter calculates for imagery data, but is intended to work with DEM data instead. This attribute measures the relative topographic position. DiffFromMeanElev
utilizes an integral image approach (Crow, 1984) to ensure highly efficient filtering that is invariant with filter size.
The user must specify a digital elevation model (DEM) (dem
) , and the size of the neighbourhood in the x and y directions (filterx
and filtery
), measured in grid size.
While DevFromMeanElev
calculates the DIFF at a single, user-defined scale, the max_difference_from_mean tool can be used to output the per-pixel maximum DIFF value across a range of input scales.
DevFromMeanElev
, max_difference_from_mean
def difference_from_mean_elevation(self, dem: Raster, filter_size_x: int = 11, filter_size_y: int = 11) -> Raster: ...