[GRASSLIST:3997] Re: How to improve the resolution of r.in.gdal?

[Glynn Clements]

Steve Kimball wrote:

> I successfully read in a USGS STDS 7.5 min DEM file with r.in.gdal.
> Using the CATD file worked nicely.
> Then using d.rast map= the display monitor resolution was not what I
> expected.
> After zooming in the elevation map was not as clear MS/DOS display 
> utility using the same data.  Is the WIND file used for raster
> resolution?

Raster import utilities import the data cell-for-cell, with no scaling
or resampling. However, most programs which access the imported raster
maps (including d.rast) will automatically rescale the raster using
the current region settings.

You can set the region boundaries and resolution to match a particular
raster using "g.region rast=...".

> Also I'd like to overlay the DEM raster data with vector data.
> So I used v.to.rast to create a raster map layer and it's resolution
> was worse than I expected.  The origional vector map had better
> rseolution.

Vector maps have infinite resolution; converting a vector map to a
raster map will always lose accuracy. But you determine the resolution
of the raster produced by v.to.rast via the region settings.

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