[GRASS-user] patching dems together

[Markus Metz]

stephen sefick wrote:
> yes still 0-296.  I think the problem is this
>
> r.info -s series_map
> nsres=1:09:25.8
> ewres=1:01:15.8736
>
> however:
> g.region -p
> projection: 3 (Latitude-Longitude)
> zone:       0
> datum:      nad83
> ellipsoid:  grs80
> north:      34:23:38.999997N
> south:      30:23:31.999996N
> west:       84:31:21.99999W
> east:       79:25:00.999989W
> nsres:      0:00:01
> ewres:      0:00:01
> rows:       14407
> cols:       18381
> cells:      264815067
>   
Hmm, doesn't make sense if you have set this region before patching. I
guess now you must post the exact commands you used in the exact order
you used them, plus grass version and operating system (wasn't it 3.0 on
Linux?).

Markus M

> any ideas,
>
> Stephen
>
>
> On Thu, Jul 9, 2009 at 1:50 PM, Markus
> Metz<markus.metz.giswork at googlemail.com> wrote:
>   
>> stephen sefick wrote:
>>     
>>> I followed the directions all set to srtm, computation region set to
>>> resolution of the coarsest (they are all the same and 00:00:01).  The
>>> map is still coming out as 7 different solid color blocks.
>>>
>>>       
>> You have set the region to include all tiles? You have zoomed to the
>> current region? The patched DEM still ranges from 0-296 only and not
>> from 9-800 (r.info -r)?
>>
>> I've done that regularly with SRTM tiles and it worked, no problems
>> (6.4.0RC5).
>>     
>>> On Thu, Jul 9, 2009 at 12:58 PM, Markus
>>> Metz<markus.metz.giswork at googlemail.com> wrote:
>>>
>>>       
>>>> stephen sefick wrote:
>>>>
>>>>         
>>>>> values range from ~-9 to ~800 there is a tile which has no elevation.
>>>>> The patched dem only ranges from 0-296.  This may be the problem.
>>>>>
>>>>>
>>>>>           
>>>> It seems that the current computational region did not include all tiles.
>>>> Try setting the computational region to include all tiles with g.region
>>>> rast=<all your tiles>.
>>>> Check the resolution of each tile with r.info -s. If they are not all
>>>> the same, use the coarsest resolution to be safe.
>>>> Check the resolution of the computational region. It must be the same
>>>> like the coarsest resolution, if not, set it to that.
>>>> Set the same color rules for all tiles. Use srtm or etopo2 but not
>>>> elevation because elevation will be different for each tile.
>>>> Display all tiles, zoom to the computational region.
>>>> Patch all tiles.
>>>> Set the same color rules to the patched DEM like to the tiles.
>>>> Add the patched DEM to the display, it should look like the previous
>>>> display with all the tiles.
>>>>
>>>> Good luck,
>>>>
>>>> Markus M
>>>>
>>>>
>>>>
>>>>         
>>>
>>>
>>>       
>>     
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