[GRASS-user] Coordinates from distances

[Daniel Victoria]

Hi Hamish,

Thanks for the help. The search and rescue exemples are realy
interesting. Just one question though. I can find v.overlay in the
grass manual but I cannot find v.overlap (for the Venn overlap
area)... is that an add on? Did not find it in the addon repository
also...

Thanks
Daniel

On Sun, Feb 5, 2012 at 6:51 PM, Hamish <hamish_b at yahoo.com> wrote:
> Daniel wrote:
>> Might be a bit off topic but here we go:
>> I need to calculate coordinates for several
>> points, something similar to m.cogo, but instead
>> of having distance + bearing information, I'll
>> have distance from at least 3 fixed, known
>> landmarks. Is there a tool already built for
>> this?
>
> not that I know of, but see also v.in.geodesic and
> v.transect(s) in addons and the r.transect module.
>
>> If not, I tough about using a combination of
>> v.buffer + v.overlay in order to cross circles
>> representing the possible location of each point
>> from the landmarks.
>
> yup, my first try would be v.buffer + v.patch +
> 'v.clean tool=break error=intersection_points', but
> the Venn overlap area made by v.overlap may be
> better if the ranges are sloppy.
>
> http://grass.osgeo.org/grass60/screenshots/images/fire2.png
>
>
> see also this previous investigation into using
> distance from cell phone towers to find lost hikers:
>
> http://grass.osgeo.org/wiki/Search_and_Rescue#Case_Studies
>
>
> Hamish