Hi Frank, my problem is that I don't understand the pdf. When I try to read it my brain gets woozy, so I started to trace what TileEncoder.cs is doing using an input file for an area in Niedersachsen and in parallel I try to code a bitstream reader in DemDisplay. I still have no clue how the reader knows in what way the numbers are coded. I think I undetstand the section with header "Datenberechnung", but the following "Standardwerte" is still a miracle...
Gerd ________________________________________ Von: mkgmap-dev <[email protected]> im Auftrag von Frank Stinner <[email protected]> Gesendet: Freitag, 10. November 2017 11:48:53 An: [email protected] Betreff: Re: [mkgmap-dev] DEM format Questions Hi Gerd, which 0-Bit you mean? Let us take this example: 4,4,4,5,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7 8,8,5,5,5,5,5,8 The detailview from my prog "Input2" (https://github.com/FSofTlpz/Garmin-DEM-Build/blob/master/Input2/bin/Input2.exe) show us: MaxHeigth=158, Codingtype=0, TileSize=64x64, BaseHeigthUnit=1, HeigthUnit=0, ActualMode=notdefined, ActualHeigth=0 Line 0 Idx=0, Plateau Length=0 TableIdx=0 Bits=0 [.] <> Idx=0, PlateauFollower ActualHeigth=4, Value=4 PlateauFollower0 [...11] Hybrid1 ddiff=0 Idx=1, ActualHeigth=4, Value=0 Standard [1.] Hybrid1 ... Idx=62, ActualHeigth=7, Value=0 Standard [1] Length0 Idx=63, ActualHeigth=7, Value=0 Standard [1] Length0 Line 1 Idx=0, Plateau Length=0 TableIdx=0 Bits=0 [.] <> Idx=0, PlateauFollower ActualHeigth=8, Value=4 PlateauFollower0 [.111] Hybrid2 ddiff=0 Idx=1, ActualHeigth=8, Value=0 Standard [1] Length0 Idx=2, ActualHeigth=5, Value=-3 Standard [......1] Length0 Idx=3, Plateau Length=4 TableIdx=3 Bits=1 [1111..] <111a> Idx=7, PlateauFollower ActualHeigth=8, Value=-1 PlateauFollower1 [.1.] Hybrid1 ddiff=2 Between the brackets [ and ] are the bits (. means 0). There is no special case. If a plateau have to begin, we have as first the plateau-length (see "Codierung der Plateaulänge"). There is ever a 0-Bit between the 2 parts of length-coding, also when plateau-length=0 (often on start of a line). As next we have the height-coding for the follower. Frank _______________________________________________ mkgmap-dev mailing list [email protected] http://www.mkgmap.org.uk/mailman/listinfo/mkgmap-dev
