This tool performs a 3 × 3 Prewitt edge-detection filter on a raster image. The Prewitt filter is similar to the sobel_filter, in that it identifies areas of high slope in the input image through the calculation of slopes in the x and y directions. The Prewitt edge-detection filter, however, gives less weight to nearer cell values within the moving window, or kernel. For example, a Prewitt filter uses the following schemes to calculate x and y slopes:

X-direction slope

| . | . | .
-1 | 0 | 1
-1 | 0 | 1
-1 | 0 | 1

Y-direction slope

| . | . | .
1 | 1 | 1
0 | 0 | 0
-1 | -1 | -1

Each grid cell in the output image is assigned the square-root of the squared sum of the x and y slopes.

The user may optionally clip the output image distribution tails by a specified amount (e.g. 1%).

## See Also

sobel_filter

## Function Signature

`def prewitt_filter(self, raster: Raster, clip_tails: float = 0.0) -> Raster: ...`

## Project Links

WbW Homepage User Manual Support WbW