[GRASS-dev] more precise zooming -- hopefully

[Michael Barton]

Thanks to various contributions, but especially to Glynn who provided
details about the mysterious workings of g.region and sent me a set of
algorithms, I think I¹ve fixed the problem with zooming in to a tiny region
for a raster map, such that the grid-cell size is much larger than display
pixels. 

This seemed to be an intractable problem. Essentially, due to the way
g.region works at these combinations of resolutions and region size (at
least this becomes apparent at this scale), the GIS Manager has to handle a
lot of the details of managing extents and resolution that g.region does in
most normal circumstances. However, Glynn¹s algorithms seem to work well on
my Mac (using x11) in UTM and latlon regions, and on one of my student¹s
Debian machines. So I¹ve gone ahead and committed this to the cvs for others
to test. 

I¹m also copying Markus. If it works well, it should be backported to 6.2.1.

Michael
__________________________________________
Michael Barton, Professor of Anthropology
School of Human Evolution & Social Change
Center for Social Dynamics and Complexity
Arizona State University

phone: 480-965-6213
fax: 480-965-7671
www: http://www.public.asu.edu/~cmbarton 

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