Hi
In the newest developer version, the raster terrain plugin in QGIS has
been significantly improved (hillshade function, relief). As part of
these improvements, it is now also possible to set this scale factor
(111120 or 370400 for feet) in the QGIS plugin. More details about the
plugin improvement, especial the relief functionality, will be described
in a blog article soon.
The work was kindly funded by the Swiss Humanitarian Aid unit
(http://www.deza.admin.ch/en/Home/Activities/Humanitarian_Aid/Swiss_Humanitarian_Aid_Unit).
Regards,
Marco
On 11.01.2012 15:11, Gerardo Jimenez wrote:
For slope calculations with lat lon coordinates and elevation units in
meters or feet you have to be aware to set the proper "scale (ratio of
vertical unit to horizal units)" value. Gdal help recomends using
111120 if vertical units are in meters and 370400 if they are in feet.
See
http://www.gdal.org/gdaldem.html
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: Wed, 11 Jan 2012 19:18:51 +0530
From: [email protected]
To: [email protected]
CC:
Subject: [Qgis-user] Slope and area/length calculations with
Geographic CRS
Respected All,
When we have to calculate area/length in polygon/line vector layers
we have to convert Geographic CRS of the layer in Projected CRS, and
in raster DEM for slope calculations the same is to be done.
I am providing continuous free practical trainings to the Government
officials in India of 5-6 days on Application of Desktop QGIS in
Watershed/Rural Development schemes and in this duration I don't want
to put the trainees deep in the matter of Coordinate Reference System
and want to do everything in GCS-WGS1984. Can there be any solution
presently or in future for calculating area/length in vector and slope
etc. in DEM with geographic coordinate system.
Regards
Harish
--
Harish Kumar Solanki, Assistant Professor
National Institute of Rural Development (NIRD), MoRD, GoI
Jaipur, INDIA- 302006
Email- [email protected] <mailto:[email protected]>,
[email protected] <mailto:[email protected]>,
Tele-Fax-0141-2209904, Mo.- 09414291732, 09214446732
Website- http://www.nird.org.in, http://watershed.rajasthan.gov.in/
<http://www.nird.org.in>
LinkedIn: www.linkedIn.com/in/hksolanki
<http://www.linkedIn.com/in/hksolanki>
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--
Dr. Marco Hugentobler
Sourcepole - Linux& Open Source Solutions
Churerstrasse 22, CH-8808 Pfäffikon SZ, Switzerland
[email protected] http://www.sourcepole.ch
Technical Advisor QGIS Project Steering Committee
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