[GRASS-user] Re: grass

[Dylan Beaudette]

On Wednesday 24 October 2007, ec.jkd at tpcsed.com wrote:
> hi,
> On a contour map i want to plot two points A an B .The requirment is to
> know if point A has a line of sight with point B. For this i started with
> r.contour but this only gives me ontour of pheripheral i.e only the outline
> and not the actual contour map with different heights. Now what i want from
> you is firslty how shoulsd i produce first contour map and then find line
> of sight. I hope you have now being clear with the subject and can help me
> bec i really need yr help. Thanking you>

Again, please post these questions to the GRASS mailing list (see email 
headers...).

Here is what I think you are trying to do:

1. determine line of sight (LOS) between points A and B

in order to do this you need:

1. a DEM of the region
2. coordinates of A and B

So: Do you have either contours to interpolate from, points to interpolate 
from, or a DEM?

If so, then carefully read the manual page for r.los

Cheers,

Dylan


>  On Tuesday 23 October 2007, ec.jkd at tpcsed.com wrote:
> > > hi,
> > >  i am working for defence sector so for that i need to know line of
> > > sight from a particular point. I am gonna used DGN map and hence i have
> > > converted this into raster.Now line of sight is giving me a problem as
> > > i am not able to find it. Can you solve my issue >
> >
> > You need to more clearly describe what you are doing, and post it to the
> > GRASS-list.
> >
> > Dylan
> >
> > > On Tuesday 23 October 2007, ec.jkd at tpcsed.com wrote:
> > > > > hi,
> > > > > I am working on grass 6.2 with a dgn map.
> > > > > now i have converted this map into raster for finding line of
> > > > > sight.using v.to.r now i used r.los in=DGN_rast out=rast_los
> > > > > coor=x,y this give me output from the given point in 360degree
> > > > > but i want to find line of sight between only two points.
> > > > > you said use mapcalc for creating a patt_map file
> > > > > Now mapcalc says
> > > > > r.mapcalc pat_map= "if(where you want,1 0)"
> > > > > eg : r.mapcalc pat_map= "if(road<5,1, 0)
> > > > > Here this "5"resembels category value ,now when i sain r.report my
> > > > > DGN_rast map have 63 cat value but it dose not give me any
> > > > > description saying what dose this cat value resembles......so help
> > > > > me with proper syntax and format Now can you tell me how should i
> > > > > fill up this syntax with this issue(los) in mind. And ya after this
> > > > > pat_map file is created then am i suppose to use r.los again and
> > > > > then how will i b able to see i.e will it be showing twom points
> > > > > and a green line or something else? Someone plz try and help me i
> > > > > am struggling for this since long .
> > > >
> > > > Can you describe the task which you are trying to solve with GRASS ?
> > > >
> > > > Dylan
> > > >
> > > >
> > > > --
> > > > Dylan Beaudette
> > > > Soil Resource Laboratory
> > > > http://casoilresource.lawr.ucdavis.edu/
> > > > University of California at Davis
> > > > 530.754.7341
> >
> > --
> > Dylan Beaudette
> > Soil Resource Laboratory
> > http://casoilresource.lawr.ucdavis.edu/
> > University of California at Davis
> > 530.754.7341



-- 
Dylan Beaudette
Soil Resource Laboratory
http://casoilresource.lawr.ucdavis.edu/
University of California at Davis
530.754.7341