benjamin.ducke at ufg.uni-kiel.de
Thu Sep 28 11:13:09 EDT 2006
I would just like to add that the curvature correction feature
has never been tested extensively, so before you want to use
it in a production environment, give it some testing to see
if it gives plausible results (maybe compare with ArcGIS generated
Mark Lake wrote:
>> Before I recommend to my boss that we use GRASS for
>> this, I wanted to confirm that r.los does, in fact, account for the
>> curvature. Unfortunately, the online manpage makes no mention of it,
>> so I
>> was wondering if anyone can tell me if it does or doesn't.
> r.los does not correct for curvature of the earth. The latest version
> of r.cva - upgraded by benjamin Ducke - does however have this option.
> You can get it from my site <http://www.ucl.ac.uk/ ~tcrnmar/> or
> Benjamin's site <http://www.uni-kiel.de/ufg/ ufg_BerDucke.htm>.
> Although r.cva is designed for multiple and cumulative viewshed
> analysis, you can use it for calculating individual viewsheds if you
> create a vector map containing the single viewpoint. Note also that
> whereas r.los returns a map containing the inclination at which target
> cells are visible, r.cva (when used to calculate one viewshed) will
> essentially just return a binary map (i.e. visible or not). You will
> also need to invoke the -f flag (see the man page) to get the effect
> you want.
> Dr Mark Lake
> Institute of Archaeology
> University College London
> 31-34 Gordon Square
> London. WC1H 0PY
> Tel: +44 (0)207 679 7495
> Fax: +44 (0)207 383 2572
> grassuser mailing list
> grassuser at grass.itc.it
Benjamin Ducke, M.A.
Institut für Ur- und Frühgeschichte
(Inst. of Prehistoric and Historic Archaeology)
Christian-Albrechts-Universität zu Kiel
D 24098 Kiel
Tel.: ++49 (0)431 880-3378 / -3379
Fax : ++49 (0)431 880-7300
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