[GRASS-dev] barscale in latlong region

[Michael Barton]

Oh well. Guess I wasn't thinking big enough.

Michael


On 7/3/07 3:54 AM, "Hamish" <hamish_nospam at yahoo.com> wrote:

> Michael Barton wrote:
>> 
>> How about making d.barscale be approximately accurate in latlon near
>> the bottom of the map and say so in the docs? Not ideal, but useable
>> perhaps.
> 
> 
> In short, no.
> 
> e.g. whole world etopo2/nasa blue marble/admin98:
>  g.region n=90 s=-90 w=-180 e=180
> 
> horizontal scale at the bottom of the map (s pole) is a singularity.
> even if you use the center of the region (equator) it is badly wrong
> over most of the map. I though about testing to see if the region was
> small enough for the scale not to change much (>1-2 pixel) over the
> spread of the map, but then it is still a different scale in the x and y
> dirs unless you are on the equator.
> 
> 
> Hamish

__________________________________________
Michael Barton, Professor of Anthropology
Director of Graduate Studies
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