[Qgis-user] Slope and area/length calculations with Geographic CRS
Gerardo Jimenez
gejst5 at hotmail.com
Wed Jan 11 06:11:40 PST 2012
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.
Seehttp://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: harry.om2000 at gmail.com
To: Qgis-user at lists.osgeo.org
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- hksolanki at nird.gov.in, harry.om2000 at gmail.com,
Tele-Fax-0141-2209904, Mo.- 09414291732, 09214446732
Website- http://www.nird.org.in, http://watershed.rajasthan.gov.in/
LinkedIn: www.linkedIn.com/in/hksolanki
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