[GRASS-dev] calculating bearing
Michael Barton
michael.barton at asu.edu
Fri May 18 01:46:50 EDT 2007
Thanks. I've incorporated this into the measurement tool for wxgrass (for
non-latlon regions).
Michael
On 5/16/07 1:40 AM, "Hamish" <hamish_nospam at yahoo.com> wrote:
> Michael Barton wrote:
>>
>> Is there a simple formula to calculate bearing if you have the
>> beginning xy of a line and the ending xy of the line?
>
> trig: angle = atan(y/x) [or atan2()]
>
> see Glynn's warnings in the archives about that going undefined at places.
>
> see also:
> g.manual m.cogo
>
> it gets ugly with lat/lon great circle calculations as the bearing isn't
> steady. (but there are map projections that help with that)
>
> I've got some matlab functions for doing this if m.cogo isn't your cup
> of tea.
>
>
> Hamish
__________________________________________
Michael Barton, Professor of Anthropology
School of Human Evolution & Social Change
Center for Social Dynamics & Complexity
Arizona State University
phone: 480-965-6213
fax: 480-965-7671
www: http://www.public.asu.edu/~cmbarton
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