[GRASSLIST:2322] Re: zoom to fill GRASS monitor

[Glynn Clements]

Wolfgang von Hansen wrote:

> > > Only 
> > > problem is, my data are lat-lon, so that's not so easy since polar 
> > > coordinates do not measure units of distance.
> > 
> > That shouldn't matter. Most of GRASS doesn't care whether the units
> > are metres, feet, degrees, micro-fathoms or whatever; they're just
> > units.
> > > 
> > Unlikely. d.rast (etc) positions and scales the image such that:
> > 
> > c) the scale factor is the same for both dimensions.
> 
> Does this include somthing like lon_display := lon_map / cos(lat) to
> get at least approximately correct aspect ratio?

No. Regardless of the coordinate system, the transformation is just
uniform scaling plus offset. E.g. for a lat-lon location, one degree
of latitude and one degree of longitude will appear the same size on
screen, regardless of the latitude.

-- 
Glynn Clements <glynn.clements at virgin.net>