slope_aspect_splitter

The slope_aspect_splitter module will split an input field into two output fields based upon the slope and/or aspect of the external face of the cell and the subset expression used.  The input field is split into two fields one for which all cells orientations are true for the subset expression, and another field for which all cells orientations are false for the subset expression.

All data from the original input is preserved in the output.

Flat Surface Aspect: If you have a flat surface then a realistic aspect can not be generated.  This field lets you set the value for those sells.

1) To output all upward facing surfaces: use the default subset expression of SLOPE < 89.9. If your object was a perfect sphere, this would give you most of the upper hemisphere. Since the equator would be at slope of 90 degrees and the bottom would >90 degrees.

(Notice there is potential for rounding errors use 89.9 instead of 90)

Note: If your ground surface is perfectly flat and you wanted only it, you could use SLOPE < 0.01, however in the real world where topography exists, it can be difficult if not impossible to extract the ground surface and not get some other bits of surfaces that also meet your criteria.

2) General expression (assuming a standard cubic building)

A) SLOPE > 0.01 (Removes the top of the building)

B) SLOPE > 0.01 and SLOPE < 179.9 (Removes the top and bottom of the building)

3) Since ASPECT is a variable it must be defined for each cell.  In cells with a slope of 0 or 180 there would be no aspect without our defining it with the flat surface aspect field

4) Units are always degrees.  You could change them to radians if you want inside the expression.  (SLOPE * PI/180)

Module Input Ports

Module Output Ports