[Qgis-user] DEM terrain models problem SOLVED

[Carlos Cerdán]

Yes, it was scale ratio!, my DEM has degree units for X Y and meters for 
elevation. Thank you very much Gerardo, Marco and Paolo, and I' so 
sorry, I didn't understand the instruccions before.

Carlos


El 16/08/11 17:27, Gerardo Jimenez escribió:
> It could be that you did not set the proper scale value. If your data 
> is in lat/lon  the scale ratio must be set at 111120. If your data is 
> in meters 1 is ok. This setting relates to "how many vertical units 
> (m) to horizontal units. Then if your data is in decimal degrees, 
> 111120 meters are equivalent to a degree. That is the reason also 
> if your data is in meters tere is 1 vertical unit to 1 horizontal 
> unit. Check this out
>
> http://www.gdal.org/gdaldem.html
>
> and go to the slope section
>
> Hope it helps
> Gerardo Jiménez Delgado
> Instituto de Investigaciones Antropológicas
> Universidad Nacional Autónoma de México
> Ciudad Universitaria s/n
> Coyoacan 04510 Mexico City
> Mexico 56 22 95 16
>
> ------------------------------------------------------------------------
> Date: Mon, 15 Aug 2011 20:47:00 -0500
> From: sig.upagu at gmail.com
> To: qgis-user at lists.osgeo.org
> Subject: [Qgis-user] DEM terrain models problem
>
> Dear QGIS list members:
>
> I've got some ASTER_GDEM data 
> (http://www.gdem.aster.ersdac.or.jp/search.jsp) and I was testing the 
> /DEM terrain models/ GDAL tool with my DEM.
>
> The shaded relief map that I got is ok, but slope map is wrong: this 
> one has 0 (zero) and over 89 degrees only, (there are not 1, 2, 
> 3....88) . I've tried all options but I got always a 0 and 89 (and 
> decimal) degress map.
>
> I've tried with the r.slope module (GRASS pluggin)  and it does a good 
> job: I get a full-slope map.
>
> My distro: QGIS 1.7 on Ubuntu 11.04. A month ago I fixed it for the 
> TIFF images problem reported here: 
> http://osgeo-org.1803224.n2.nabble.com/gdal-1-8-0-no-tiff-support-anymore-in-Ubuntu-11-04-Natty-tc6365327.html  
> It is relationed with this slopes problem?
>
> As I said, the GRASS pluggin did the right work, but I'd liked GDAL 
> tool does too. Perhaps I did something wrong or Is something wrong 
> with this tool?
>
> Thank you in advance for sugestions
>
> Regards from Cajamarca - Perú
>
> Carlos Cerdán
>
>
>
>
>
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