[GRASS-user] Clipping Raster Map
hamish_b at yahoo.com
Fri Jan 1 19:24:54 EST 2010
> > I doubt it. The most likely reason for a difference is if the current
> > region has a much higher resolution than the display.
please post the output of
r.info -gs $mapname
how long are we talking about to render here, 2 seconds or 20?
> > Modules which read raster maps normally resample them
> to the current
> > region. The display library then resamples the data to
> the display
> > resolution.
> That's what I thought, but apparently it's not working properly
> because I'm not doint something correctly.
g.copy only copies files*, it doesn't resample. if your base raster map
is stored in PERMANENT or somewhere else in your mapset search path then
there is usually little need to make a local copy, it will resample on
the fly as needed, at full speed.. "copy" with r.resamp* or r.mapcalc
if you want a new map which really is cropped
* well, g.copy + vectors are a bit of an exception
> When I copy the raster DEM from the source directory
> to the project directory (much smaller bounds),
how do you copy it?
> and view the map in the GUI, I see the
> whole map, not the portion only within the project bounds.
the g.region bounds is the important one.
> I've not yet figured out how to overlay the project bounds vector
> map on the raster map.
in the GUI you can drag layers above and below each other to change
> Well, the current region is set appropriately, but I see the entire
> DEM map when I load it, not just the appropriate portion.
from the command line + d.mon, you see what g.region has the current zoom
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