[mkgmap-dev] mkgmap r4022 ready

Thu Dec 28 12:28:51 GMT 2017

Having a rectangular dem outside of the area covered by any map looks 
strange, no matter if it's sea or land, so I think best solution would 
be to cut DEM using the same *.poly used to define map area.

El 28/12/17 a las 12:04, Henning Scholland escribió:
> 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