[mkgmap-dev] DEM-file generation from geo-tiff sources ?

Sat Jan 6 17:58:27 GMT 2018

Hi Henning,

yes, we have specialized tools for this work, they make a good job and we should use this tools.

A little interesting idea is: If we can use additional use tif's a "container" for dem data, we can safe space on the hd. My little test with the 
copernicus files show: 5.2GB for zipped hgt's and only 3,54GB for the tif's with lzw compression (round about 68%).
"container" means: only use 16-bit grayscale values, no metadata, no coordinate reference system or whatever. A "on-the-fly-conversion" is to expensive.

You ask: Are the copernicus-files so much better compared to the viewfinder-hgt files?

How we can decide this? I believe, there is no way. I have not found any information about the +- interval for SRTM or the viewfinder-data. I only 
know, that the copernicus-files have the 25m resolution from tanger up to the north cape in norway.

Frank

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