Contours shapefiles were generated from the elevation grid. The input elevation grid represented Z-values rounded to the nearest 1/10th of a foot with each cell spaced by 20 feet along the X & Y. For details on how this was generated, please read the XML metadata included with this shapefile.
Elevation was rounded to the nearest foot by this calculation:
Elevation = INT(RealElevation + 0.5)
To create the hillside shading, with 126 shades of gray, a z-factor of 3 added to 1.5 was used. This exaggerates the relief (surface) to create
the more extreme shading. Calculation used for 126 shades:
Hillshade = INT((HILLSHADE(Elevation,315,45,all,3) / 4) + _
(HILLSHADE(Elevation,315,45,all,1.5)) / 4)
with Azimuth = 315, Altitude = 45, and Z-Factor = 3 and 1.5
This location of sun is impossible in the Northern Hemisphere but is standard for hillside shading.
Slope was resampled to a 10-foot cell spacing and rounded to the nearest 10 degrees by these two calculations:
TempElevation = INT(RESAMPLE(Elevation, 10, BILINEAR) + 0.5)Slope = INT ((SLOPE(TempElevation, 1, DEGREE) / 10) + 0.5) * 10