[GRASSLIST:2469] Re: native resolution of raster maps

[Ian Macmillan]

In addition you can actually get a smaller resolution in a lat-long location,
just use decimal degrees.

For example you can do

g.region nsres=0.00013889 ewres=0.00013889
(this corresponds to ~15m resolution)

or you can set a region to the boundary of a raster, and a different resolution
at the same time.

g.region raster=your_rast nsres=0.000833 ewres=0.00083

Good luck, ian



> Presuming I'm understanding the question right, what you're looking for 
> is just:
> g.region rast=nameofexistingmap
> 
> to make the current region match that of the existing map.
> 
> But that's only part of the question, because it sounds like you're 
> mixing things with different spatial units?  Or maybe you mean that the 
> resolution _corresponds_ to 10m resolution but is actually in lat/long 
> coordinates/units?
> 
> Scott Mitchell

> > Is there a way to find out the native resolution of a raster map and 
> > _set_it_ using g.region?
> >
> > I'm concerned about making sure that raster operations (such as 
> > r.patch) occur at the native resolution of the maps involved, not the 
> > resolution of the region.  The reason that this concerns me is that I 
> > noticed that the grid resolution setting of g.region only goes down to 
> > 1 sec (in a lat-lon location).  If I calculate correctly, that's about 
> > 30m.  What if I have data that have, say, a 10m resolution?  Can I not 
> > perform operations on those data at their native resolution because 
> > g.region won't let me set the resolution low enough?  For maps that 
> > have a resolution higher than 30m, how do I set the resolution in 
> > g.region to exactly match the native resolution of the map.  Right 
> > now, I'm guessing and I'm afraid that I'm loosing data.
> >
> > As always, thanks ahead of time,