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[mkgmap-dev] what do the 0x4a polygon in the mean?

From Andrzej Popowski popej at poczta.onet.pl on Sat Jan 13 16:24:35 GMT 2018

Hi Gerd,

 > 1) don't add DEM to overview map (a work around)

Maybe it would work, but I remember getting problems with overview 
without DEM (I forgot what it was, maybe even not because of DEM?). I 
think it would be better to add what I call "empty DEM" instead.

The empty DEM layer contains 4 bytes of data: 0 0 0 2
Header of a layer is the same, tiles are 64*64, but there is no tiles, 
only extra rows and columns. Word defining structure (recordDesc) is 
0x10 00. Number of rows and columns is small, like for example 4, and 
distance between points is big.

You can see this in Adria Topo. There is update here, which can be 
installed on PC (including Mapsource):

Link to map doesn't work because of redirections, but you can extract 
final address from link and download map. You can even browse map in 
Mapsource, if you provide unlock key: DEMO

 > 2) use a slightly smaller polygon

This is other solution of Garmin, but they use bigger polygon in 
overview, increased by about 700m outside. So jaggies are far from map 

 > 3) Find a flag or something else that tells the PC program that it 
should stop rendering the overview DEM at some level.

I doubt it is possible.

Best regards,

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