[mkgmap-dev] mkgmap r4022 ready

Thu Dec 28 11:04:31 GMT 2017

Hi Gerd,

I don't see an issue for Switzerland map, having a complete
DEM-rectangle. But on maps with sea it looks strange. Eg. for my Chinese
map it would be fine, showing DEM of Mongolia, Northern India etc., but
it looks strange to have a rectangular cut sea and then showing DEM of
Korean peninsula or Japan without rough sea area around. As it's
indicating to me, there is something broken/missing. So I think having
additional sea data in overview map it would look less strange.

But maybe others think different and of course this additional data
increases file size...and of course it's only working, if you use
external sea data, as there is no data in the data-tiles.

Henning

On 28.12.2017 11:47, Gerd Petermann wrote:
> Hi Henning,
>
> I don't understand what you mean with "create sea polygons". It would be rather easy to fill the map overview map with them,
> but I think it would look strange for a map of Switzerland.
>
> reg. compressed files: Yes, mkgmap can read e.g. osm.zip or osm.bz2, but for hgt it does not (yet) work.
> I've used code for the hgt reader which depends on random access files (MappedByteBuffer).
> I'll see if performance is very different when using compressed files.
>
> Gerd
>
> ________________________________________
> Von: mkgmap-dev <mkgmap-dev-bounces at lists.mkgmap.org.uk> im Auftrag von Henning Scholland <osm at hscholland.de>
> Gesendet: Donnerstag, 28. Dezember 2017 11:21:45
> An: mkgmap-dev at lists.mkgmap.org.uk
> Betreff: Re: [mkgmap-dev] mkgmap r4022 ready
>
> Hi Gerd,
>
> another solution from 'nice looking' point of view except not creating
> DEM would be to also create sea polygons for the whole rectangle. But I
> guess it's pretty hard as it needs data tiles, am I right? For users of
> course it would be better to define an poly-file, where DEM should be
> created, as these poly-files already exists.
>
> Btw.: http://www.hscholland.de/OSM/HGT.7z you can find the 'broken'
> hgt-files where I got the problem Gerd pointed out. Viewfinder-data are
> fine so far.
>
> Can mkgmap read already compressed hgt-files? I remember previously
> mkgmap was able to read bzip2 or gz-compressed osm-files. So there are
> maybe already classes for reading compressed data in mkgmap.
>
> Finally I want to thanks all of you for the great work! I even don't
> know how long I was waiting for this feature!!!
>
> Henning
>
> On 28.12.2017 11:01, Gerd Petermann wrote:
>> Hi all,
>>
>> see the log message http://www.mkgmap.org.uk/websvn/revision.php?repname=mkgmap&rev=4022
>> for details about the changes.
>>
>> I've also experimented with code to read a *.poly file and use that to define an area for which mkgmap should
>> not calculate DEM data but was not happy with the results so far. Maybe I'll try again.
>>
>> Henning has pointed me to an error:
>> It seems that mkgmap (and probably also BuildDEMFile) somtimes create invalid DEM data
>> for areas where the hgt files contain large holes, esp. when resolution is low (high dem-dist value).
>> See e.g. http://files.mkgmap.org.uk/download/377/holes.jpg
>> I try to find out more now.
>>
>>
>> Gerd
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>> mkgmap-dev at lists.mkgmap.org.uk
>> http://www.mkgmap.org.uk/mailman/listinfo/mkgmap-dev
>>
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