Hello to everybody,
I'd like to ask two questions considering r.los
1. Is there an estimation of the time that r.los will be implemented for
Lat-Long projections too?
2. Is there a similar module, or a way usinf r.los, to compute los
coverage in a specific altitude above the ground (i.e. 2000m)?
Thanks a lot
Antonios
On Sun, 2007-07-29 at 18:54 +0300, atlasis@telecom.ntua.gr wrote:
1. Is there an estimation of the time that r.los will be implemented for
Lat-Long projections too?
Not really. It's on my list of 100000 things to do...very low on the
list. Not terribly difficult to implement, but my time is being used
elsewhere. 
2. Is there a similar module, or a way usinf r.los, to compute los
coverage in a specific altitude above the ground (i.e. 2000m)?
r.los obs_height=2000 in=in_map out=out_map coord=x,y
option "obs_height" is your height above ground.
Unless I'm working with a large region, I find it generally best to
reproject in a more specific projection/datum. It does depend somewhat
on the data I'm working with, though.
--
73, de Brad KB8UYR/6 <rez touchofmadness com>
I ended up having to install the cumulative viewshed analysis for lat/lon. I would appreciate if someone could write up how to do the reprojection so that I could use r.los with lat/lon. Don't be afraid to dumb it down.
Brad Douglas wrote:
On Sun, 2007-07-29 at 18:54 +0300, atlasis@telecom.ntua.gr wrote:
1. Is there an estimation of the time that r.los will be implemented for
Lat-Long projections too?Not really. It's on my list of 100000 things to do...very low on the
list. Not terribly difficult to implement, but my time is being used
elsewhere.2. Is there a similar module, or a way usinf r.los, to compute los
coverage in a specific altitude above the ground (i.e. 2000m)?r.los obs_height=2000 in=in_map out=out_map coord=x,y
option "obs_height" is your height above ground.
Unless I'm working with a large region, I find it generally best to
reproject in a more specific projection/datum. It does depend somewhat
on the data I'm working with, though.
gary wrote:
I ended up having to install the cumulative viewshed analysis for
lat/lon.
Does r.cva really do the calculation or does it just fail to warn that the
results might be wrong?
Hamish
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Mon 30 Jul 2007 11:13, Hamish wrote:
gary wrote:
> I ended up having to install the cumulative viewshed analysis for
> lat/lon.Does r.cva really do the calculation or does it just fail to warn that the
results might be wrong?
IIRC the ben ducke version as (some) support for earth curvature, so..
..but this is from my memory and i haven't tried lat/lon with r.cva so
far.
otherwise i much prefer r.cva to r.los.
interesting is also the IOviewshed research ..
http://www.bowdoin.edu/~ltoma/research.html
I believe the CVA results were correct using lat/lon.
Hamish wrote:
gary wrote:
I ended up having to install the cumulative viewshed analysis for lat/lon.
Does r.cva really do the calculation or does it just fail to warn that the
results might be wrong?Hamish
____________________________________________________________________________________
Need a vacation? Get great deals
to amazing places on Yahoo! Travel.
http://travel.yahoo.com/
On Mon, 2007-07-30 at 11:57 +0300, atlasis@telecom.ntua.gr wrote:
On Mon, July 30, 2007 02:12, Brad Douglas wrote:
> On Sun, 2007-07-29 at 18:54 +0300, atlasis@telecom.ntua.gr wrote:
>
>> 2. Is there a similar module, or a way using r.los, to compute los
>> coverage in a specific altitude above the ground (i.e. 2000m)?
>
> r.los obs_height=2000 in=in_map out=out_map coord=x,y
>
> option "obs_height" is your height above ground."obs_height" corresponds to the the height of the "antenna", right? I
mean, it corresponds to the altitude from which the observer "looks" at
the area, correct?
Correct. In this case the observer is an antenna.
If yes, I'm interested in computing the los coverage in a specific
altitude above the ground for all the surrounding area (i.e., if an
aircraft flies at 5000ft above the ground, I want to compute the los
coverage from the observing point at this altitude level to check if the
aircraft is in the los coverage).
r.los is not the best piece of software to model antenna/RF links. It
does not take Fresnel effects, antenna orientation, or pattern into
account.
I added dirty support for 1st Order Fresnel effects for a couple UHF
bands some time ago, but it needs a lot more work if I'm going to
release it as a module. It did what I needed it to do and nothing more.
--
73, de Brad KB8UYR/6 <rez touchofmadness com>