Hi Gerd I replied to your patch a couple of months ago, but I have now realized it didn't arrive to the list (it seems I used and old address). I was surprised you didn't say anything, but didn't want to bother... I used your binary for my test. Today I have tried to apply your patch, but it seems to be generated against a different version of files in trunk. -------- Mensaje reenviado -------- Asunto: Re: [mkgmap-dev] "Small" SRTM1 files and DEM maps Fecha: Tue, 21 Apr 2020 17:38:19 +0200 De: Carlos Dávila <cdavilam@orangecorreo.es> Para: mkgmap-dev@lists.mkgmap.org.uk Hi Gerd I have tested it in an area of 4x10 degrees, in the North of China, and it worked fine. El 21/4/20 a las 14:40, Gerd Petermann escribió:
Hi Carlos,
please try the attached patch or this binary based on r4483: http://files.mkgmap.org.uk/download/468/mkgmap.jar I hope I found all the places that need to be changed. I've only tested with a map around the point N50 E118.
Gerd
________________________________________ Von: mkgmap-dev <mkgmap-dev-bounces@lists.mkgmap.org.uk> im Auftrag von Carlos Dávila <carlos@alternativaslibres.org> Gesendet: Dienstag, 21. April 2020 11:27 An: mkgmap-dev@lists.mkgmap.org.uk Betreff: Re: [mkgmap-dev] "Small" SRTM1 files and DEM maps
Great new!! Thanks for your support
El 21/4/20 a las 11:19, Gerd Petermann escribió:
Hi Carlos,
yes, I see that the source code handles this format. I finally found https://dds.cr.usgs.gov/srtm/version2_1/Documentation/MIL-PDF-89020B.pdf I think "TABLE I. Matrix intervals for DTED Level 0." shows how to interpret the data. It seems there are a few more variants... For now I'll try to support also the 1801 * 3601 * 2 format
Gerd
________________________________________ Von: mkgmap-dev <mkgmap-dev-bounces@lists.mkgmap.org.uk> im Auftrag von Carlos Dávila <carlos@alternativaslibres.org> Gesendet: Donnerstag, 16. April 2020 17:41 An: mkgmap-dev@lists.mkgmap.org.uk Betreff: Re: [mkgmap-dev] "Small" SRTM1 files and DEM maps
HI Gerd I don't think conversion is wrong. If input geotiff file is 24MB, output hgt file is 24 MB, if input tiff is 12MB, output hgt is 12MB I use this command on Linux: for i in *.tif ; do gdal_translate -strict -q -eco -of SRTMHGT $i `basename $i tif`hgt ; done ; rm -f *.hgt.aux.xml BTW, gdal is also able to deal with small SRTM files
El 16/4/20 a las 11:31, Gerd Petermann escribió:
Hi Carlos,
so your conversion routine is wrong. The file size is 12.970.802 bytes. There is no integer n for which 2 * n^2 results in this value.
Gerd
________________________________________ Von: mkgmap-dev <mkgmap-dev-bounces@lists.mkgmap.org.uk> im Auftrag von Carlos Dávila <cdavilam@orangecorreo.es> Gesendet: Donnerstag, 16. April 2020 11:19 An: mkgmap-dev@lists.mkgmap.org.uk Betreff: Re: [mkgmap-dev] "Small" SRTM1 files and DEM maps
Hi Gerd Forgot to mention files are downloaded as geotiff, but I then convert them to hgt, sorry. You can download a sample one from https://alternativaslibres.org/tmp/N50E118.hgt
El 16/4/20 a las 9:18, Gerd Petermann escribió:
Hi Carlos,
are you talking about geotiff format? I think someone documented how that format can be converted to *.hgt. Can you post a link to such a file?
Gerd
________________________________________ Von: mkgmap-dev <mkgmap-dev-bounces@lists.mkgmap.org.uk> im Auftrag von Carlos Dávila <cdavilam@orangecorreo.es> Gesendet: Montag, 13. April 2020 14:08 An: mkgmap-dev@lists.mkgmap.org.uk Betreff: Re: [mkgmap-dev] "Small" SRTM1 files and DEM maps
Hi Gerd They are downloaded by phyghtmap. This is what I found digging into phyghtmap files: |def getSRTMFileServer(self, resolution, srtmVersion):|| || if srtmVersion == 2.1:|| || return "https://dds.cr.usgs.gov/srtm/version2_1/SRTM{0:d}".format(resolution)|| || elif srtmVersion == 3.0:|| || if resolution == 1:|| || urlRe = "https://earthexplorer.usgs.gov/download/8360/SRTM1{:s}V3/GEOTIFF/EE"|| || elif resolution == 3:|| || urlRe = "https://earthexplorer.usgs.gov/download/4960/SRTM3{:s}V2/GEOTIFF3/EE"|| || return urlRe| They should come from the second URL above.
El 13/4/20 a las 8:24, Gerd Petermann escribió:
Hi Carlos,
sorry for the late response. I found no hint on the phyghtmap page http://katze.tfiu.de/projects/phyghtmap/ regarding a new format for srtm data. The hgt format is not compressed. Do you know from where these 12.4 MB files came from?
Gerd
________________________________________ Von: mkgmap-dev <mkgmap-dev-bounces@lists.mkgmap.org.uk> im Auftrag von Carlos Dávila <cdavilam@orangecorreo.es> Gesendet: Samstag, 11. April 2020 17:09 An: Development list for mkgmap Betreff: [mkgmap-dev] "Small" SRTM1 files and DEM maps
I use phyghtmap to build contour lines and also to download hgt data that I then use to build DEM maps with mkgmap. For a long time, SRTM1 files (and also VFP1) have all been ~24.7 MB in size, but lately (I don't remember since when) SRTM1 are also served as 12.4 MB files. phyghtmap is able to generate contour lines from those small files, as they seem to contain the same information but with a different compression ratio, but mkgmap fails to read them, and report them as missing. Would it be possible to get support for such files in mkgmap? _______________________________________________ mkgmap-dev mailing list mkgmap-dev@lists.mkgmap.org.uk http://www.mkgmap.org.uk/mailman/listinfo/mkgmap-dev _______________________________________________