On 10/16/15 08:56, Oliver Eichler wrote:
> Hi Flo
> 
> hill shading and slope colouring are derived from the DEM data by QMS.
> Contour lines are not done.
> 

Ok, good to know. So it's not a matter of the DEM source I use.

> 
> If someone is interested have a look into:
> 
> void CDemVRT::draw(IDrawContext::buffer_t& buf)
> 
> 
> The code reads the DEM data in small chunks of data (tiles). The data is
> used to derive a pixmap tile to be displayed. Usually a tile is 64x64
> points. The data read is 66x66 points. That is important to derive the
> points at the borders correctly. So the task is to derive contour lines
> for those tiles.
> 

Thank you for this explaination. I am not sure if I will take the time
to look into that in the near future ...

Thanks.

Flo.

> Am 16.10.2015 um 00:49 schrieb Flo:
>>
>> On 10/13/15 15:00, Oliver Eichler wrote:
>>> Hi Flo,
>>>
>>> I never missed that feature at all as my topographic maps have those
>>> lines included. Ages ago there where transparent Garmin files with
>>> elevation lines to be used as overlay on the devices. This will work
>>> with QMS, too. But usually these lines are of bad quality. The used
>>> algorithms fail miserably at steep slopes.
>>>
>>> I never tried to add vectorial maps to a *vrt. I would expect them to
>>> fail. But I can't tell for sure.
>>>
>> The DEM data I am using are put together with a .vrt file. The single
>> 'images' are .hgt files.
>>
>> Is the functionality of coloring slopes (corresponding to their
>> steepness) included in these files or is this part of Qmapshack?
>>
>> Best Regards,
>> Flo
>>
>>>> Hi,
>>>>
>>>> Right now I am using
>>>> http://www.viewfinderpanoramas.org/Coverage%20map%20viewfinderpanoramas_org3.htm
>>>> to download the DEM data from a specific region. If I mark the checkbox
>>>> I can have the hillshade or steepness of the slopes be displayed on top
>>>> of the underlying maps.
>>>>
>>>> Strange enough I haven't found anything like this for contour lines as
>>>> this would be really useful. Maybe with adjustable colors to increase
>>>> the contrast to the underlying map (or satellite images).
>>>>
>>>> Thanks for hints.
>>>>
>>>> Flo
>>>>
>>>> PS: At my research I found http://opendem.info . They provide zip files
>>>> for most of the regions. Maybe those help. But when I want to build a
>>>> vrt there is the error message: 'Unable to find field `location' in DBF
>>>> file' (BTW: There is a .dbf, .prj, .shp and .shx). Any help on that?
>>>> Thanks again.
>>>>
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