Foundation Altitude Anomalies

[markkampe]

I have observed several problems w/foundation Altitude maps:

• gentle slopes do not (to the eye) seem to use the full white range ... but data dumps suggest that we do.
• I observed a fine black grid ... which was resulting from an off-by-one error.
• long period well-defined waves in shallow slopes. This is almost surely a result of the altitude interpolation from the nearest neighbors; When we move far enough to replace one nearest neighbor with another, there will be a discontinuity in the interpolated altitudes, and these neighbor swaps have a periodicity.
• rivers break up before reaching the ocean ... I was unable to duplicate this problem in Aug 22.
• a Moire' pattern on steep slopes ... created by Gaussian blurring?