Does r.in.gdal use the rrd files (the ones that build pyramids to speed up viewing) when importing img files? A bunch of land cover images that I downloaded came with rrd files (in addition to the imgs, and I'm trying to figure out if grass uses them).
Thanks,
Kirk
Kirk Wythers wrote:
Does r.in.gdal use the rrd files (the ones that build pyramids to speed up viewing) when importing img files? A bunch of land cover images that I downloaded came with rrd files (in addition to the imgs, and I'm trying to figure out if grass uses them).
Kirk,
r.in.gdal does not exactly import overviews from any of it's input formats.
However, GDAL does support overviews in Imagine files (.rrd files) so if
you tried to import a big imagine files withoverviews into a low resolution
location r.in.gdal would pull from an overview to speed up the import.
Best regards,
--
---------------------------------------+--------------------------------------
I set the clouds in motion - turn up | Frank Warmerdam, warmerdam@pobox.com
light and sound - activate the windows | http://pobox.com/~warmerdam
and watch the world go round - Rush | President OSGeo, http://osgeo.org
On Jul 27, 2007, at 9:13 AM, Frank Warmerdam wrote:
Kirk Wythers wrote:
Does r.in.gdal use the rrd files (the ones that build pyramids to speed up viewing) when importing img files? A bunch of land cover images that I downloaded came with rrd files (in addition to the imgs, and I'm trying to figure out if grass uses them).
Kirk,
r.in.gdal does not exactly import overviews from any of it's input formats.
However, GDAL does support overviews in Imagine files (.rrd files) so if
you tried to import a big imagine files withoverviews into a low resolution
location r.in.gdal would pull from an overview to speed up the import.
Thanks Frank,
Does r.in.gdal know to do that automagically (as long as the rrd files are in the same directory as the img files)? or is there a flag that needs to be set on the import?
Kirk
Best regards,
--
---------------------------------------+--------------------------------------
I set the clouds in motion - turn up | Frank Warmerdam, warmerdam@pobox.com
light and sound - activate the windows | http://pobox.com/~warmerdam
and watch the world go round - Rush | President OSGeo, http://osgeo.org
Kirk Wythers wrote:
On Jul 27, 2007, at 9:13 AM, Frank Warmerdam wrote:
Kirk Wythers wrote:
Does r.in.gdal use the rrd files (the ones that build pyramids to speed up viewing) when importing img files? A bunch of land cover images that I downloaded came with rrd files (in addition to the imgs, and I'm trying to figure out if grass uses them).
Kirk,
r.in.gdal does not exactly import overviews from any of it's input formats.
However, GDAL does support overviews in Imagine files (.rrd files) so if
you tried to import a big imagine files withoverviews into a low resolution
location r.in.gdal would pull from an overview to speed up the import.Thanks Frank,
Does r.in.gdal know to do that automagically (as long as the rrd files are in the same directory as the img files)? or is there a flag that needs to be set on the import?
Kirk,
It is automatic as is the nature of GDAL for this sort of thing.
Best regards,
--
---------------------------------------+--------------------------------------
I set the clouds in motion - turn up | Frank Warmerdam, warmerdam@pobox.com
light and sound - activate the windows | http://pobox.com/~warmerdam
and watch the world go round - Rush | President OSGeo, http://osgeo.org
Fri 27 Jul 2007 16:13, Frank Warmerdam wrote:
r.in.gdal does not exactly import overviews from any of it's input formats.
However, GDAL does support overviews in Imagine files (.rrd files) so if
you tried to import a big imagine files withoverviews into a low resolution
location r.in.gdal would pull from an overview to speed up the import.
IMO this should make it into the otherwise excellent documentation.
http://www.gdal.org/frmt_hfa.html says regarding write support..
| If overviews are generated, they will be in an external .ovr (GeoTIFF
| file) recognised only by GDAL, not in the .rrd format produced by
| Imagine.
..so one might (wrongfully) believe there's also absolutly no read support
for .rrd files.