[mkgmap-dev] DEM format Questions

Fri Nov 10 12:20:21 GMT 2017

Hi Gerd,

we have ever 2 problems: how to calculate the next value and how we have 
to encoding this value.

#1: If we have not a plateau, then we have a "Standardwert". For the 
calculation of a "Standardwert" we have to 3 differend cases depend on the 
value hdiff(n, m-1) = h(n, m) - h(n-1, m) (horizontal difference, see at 
the end of "Datenberechnung"). max is highest possible value in this 
64x64-subtile.

#2: We have to decide, is it "Längencodierung", "Hybride Codierung" or if 
they are not possible, "Binärcodierung für große Zahlen". But we have no 
choice, we have to use that kind, that the algorithms say (see "
Umschaltung der Codierart"). That do in TileEncoder.cs the class 
CodingType and the derived classes.

I'm sorry, but TileEncoder.cs is not written for speed or good 
understanding. It is only for exploring DEM and, in Input2, for showing, 
what's going on. There is much place for optimizing. ;)

Frank
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