Syntax

   @RasterAspect([REJECTABLE], [<interpolate nodata>[, <algorithm>]])

Arguments

   REJECTABLE

      Specifies if the function will supply a rejection code and message
      to the invalid feature and output it to the rejected port, or will
      fail upon being supplied invalid features.

      A feature can be rejected for the following reasons:
         - The feature has invalid geometry

   <interpolate nodata>

      Whether to calculate values at raster edges and near nodata values.

      When this is set to 'DoNotInterpolateNodata', there will be a one pixel
      border around the edge of the raster set to the nodata value.
      Additionally, when any pixel in the 3x3 window used to calculate the
      aspect value is equal to nodata, the output pixel will also be set to
      nodata.

      When this is set to 'InterpolateNodata', values around the edge and near
      nodata values will be estimated by interpolating missing values.

      Range: InterpolateNodata | DoNotInterpolateNodata

   <algorithm>

      The algorithm used to calculate aspect.

      Some analyses have suggested that Horn's formula is better suited to
      rougher terrain, whereas Zevenbergen & Thorne's formula is better for
      smooth terrain.

      Range: Horn | ZevenbergenThorne

Description

   The @RasterAspect function calculates the aspect (direction of slope)
   for each selected band of a raster. Aspect is measured in degrees from
   0 to 360, starting clockwise from the north.

   Each selected input band will be converted to a REAL64 band with output
   values that represent the aspect. If an input band does not have a
   nodata value, the output band nodata value will be set to -1.

   This function supports raster band selection. @SelectRaster can be used
   to modify selection.