[GRASS-dev] Re: [GRASS-user] How to find out an angle between to points on the map (for r.plane, r.lake)

Martin Landa landa.martin at gmail.com
Sat Mar 1 10:59:12 EST 2008


2008/3/1, Michael Barton <michael.barton at asu.edu>:
>  >>  Ignoring geodetic distance for LL projections is simply ignorance
>  >> (on
>  >>  my part here) of the equations needed to do it. It's easy to
>  >>  determine if a location is LL. In that case, it should calculate
>  >>  geodetic distance rather than (or perhaps in addition to) displaying
>  >>  distance in map units. Just need to have the functions to do this
>  >>  added to the measurement methods.
>  >
>  > why to code it in Python when it is already available in gislib? We
>  > should avoid code duplication.
> Certainly. If a new version of d.measure or a hypothetical g.measure
>  could be created, we could use that. Until that happens, we'll need
>  to do it in Python (which is not all that bad). Is there anyway to
>  access gislib directly from Python? This could be an alternative to
>  creating a new module or changing an existing one.

yes, via SWIG interface, see ./swig/python. Anyway the SWIG-Python
interface for GRASS is a bit limited, need to be improved.


Martin Landa <landa.martin gmail.com> * http://gama.fsv.cvut.cz/~landa *

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