Hi all,

FYI: 
r4006 in the dem-tdb branch implements a new option
--x-dem=path_to_dir_with_hgt_files

It will crash if any hgt file is missing, probably there are also other stupid 
problems, e.g. with negative lat/lon values.

It cannot (yet) read zip files, so the directory must contain unzipped *.hgt 
files.
The hgt files can be in 3'' or 1'' resolution, but for now DEM data is always 
stored with 3'' res.
I plan to change that soon, so that 1'' is used if at least a part of the tile 
is covered by 1'' SRTM data.

It doesn't yet create DEM for the overview map and it only creates DEM for 
level 0.
So far I've only implemented a very basic hgt reader which doesn't do any 
interpolation,
this might change soon.
I did not check if the flags in the tdb file are set correctly now, I've only 
created some small
maps for parts of the alps so far and they looked good in Basecamp /Mapsource.

If you want to try this version, see 
http://www.mkgmap.org.uk/download/mkgmap-dem-tdb-r4006.zip

@Frank:
My currennt understanding is that mkgmap should do the calculation of the DEM 
resolution based on the 
levels used to create the rest of the map. I have to find out how to calculate 
the values for lower resolutions.
I assume it has to be the average of the values, so if at res 24 we have 4 
points with 123, 124,128, and 122 
the value for res 23 would be Math.round((123+124+128+122)/4) = 124. For res 22 
it would be the average of 4*4=16 values,
and so on. Does that make sense?

ciao,
Gerd
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