[GRASS5] Angle of incidence in viewshed/line of sight

Well, I have done some experimenting installing binaries
on different systems
and found that it works better than I expected.
Most Linux distributions in use today are pretty compatible
regarding basic system libs and since newer version of those
libs are usually backward copatible, one could compile
a version on an older system and newer once should be able
to run it.
I expect even less trouble from MacOS and Windows;
cross-compilers for these plattforms seem to be available
for Linux.
Basically, once the final GRASS 6 gets out, it should
be possible to provide binaries of add-on C modules,
that can just be copied into /usr/local/grass/bin or
wherever the user installed to.

I am still working on getting things to compile from
source outside the GRASS source tree.
For this to work, I have to re-arrange a lot of my source
code. Since I have been busy with other coding these
last weeks, there is no progress here, but it is the
next thing I am going to look into.

Regards,

Benjamin.

----- Originalnachricht -----
Von: Michael Barton <michael.barton@asu.edu>
Datum: Dienstag, 8. März 2005 6:51 am
Betreff: Re: [GRASS5] Angle of incidence in viewshed/line of sight

Benjamin,

How are you coming on a way to install code like this without
compiling or
recompiling GRASS?

Michael
____________________
C. Michael Barton, Professor of Anthropology
School of Human Evolution and Social Change
PO Box 872402
Arizona State University
Tempe, AZ 85287-2402
USA

Phone: 480-965-6262
Fax: 480-965-7671
www: <www.public.asu.edu/~cmbarton>

> From: Benjamin Ducke <benducke@compuserve.de>
> Organization: FU Berlin
> Date: Thu, 3 Mar 2005 21:33:12 +0100
> To: <grass5@grass.itc.it>
> Subject: Re: [GRASS5] Angle of incidence in viewshed/line of sight
>
> On Wed, 2 Mar 2005 13:28:14 +1300
> Hamish <hamish_nospam@yahoo.com> wrote:
>
>>> Just so we don't re-invent the wheel, has anyone developed the
code>>> for evaluating the angle of incidence from a single point
in the
>>> landscape (i.e. the point used for r.los) to cells within the
>>> viewshed? I am analyzing repeated historical topographic survey
>>> photographs (more on this later) and want to account for
components of
>>> registration and classification error due to terrain (angle of
>>> incidence). I have looked at the code for r.los and r.sun and
will be
>>> seeking help from some students in our new computer
science/geomatics>>> programme as I am not (yet) a programmer. Look
forward to any
>>> suggestions...
>>
>>
>> Yes, I have done this some time ago.
>>
>> I modified r.los to return horizontal angle to target instead of
>> vertical angle to target for the values in the resultant raster
map. This
>> was for GRASS 5.0, but it should work for 6.0 just as well I
think. If
>> you want I can supply the code.
>>
>> r.los is a real mess and doesn't scale well to larger grid sizes.
>>
>> Be sure to check out r.cva as well:
>> http://www.ucl.ac.uk/~tcrnmar/GIS/r.cva.html
>>
>
> The GRASS 5 version of r.cva is currently broken due to a bug
> in the floating point raster code I introduced myself (ahem).
> I will have finished an updated version for GRASS 6 next week
> that fixes the bug, handles vector points for observer positions
> and introduces attributes for observer positions just
> like Argh!nfo's Spatial Analyst uses.
> I'll ask Mark Lake to update the file on his webpage then.
>
> Regards,
>
> Benjamin.
>
>
>
>>
>> r.sunmask with altitude and azimuth options might be another way.
>>
>>
>>
>> Hamish
>>
>> _______________________________________________
>> grass5 mailing list
>> grass5@grass.itc.it
>> http://grass.itc.it/mailman/listinfo/grass5
>

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