maven apache wrote:
Hi all :In fact I have post this
question,but not got a answer/
I am using win grass 6.3, when export the raster
data to tiff ,I can use two command
>1
1) r.out.gdal use this command the tiff I got
is blank,and I am sure that this tiff has the correct crs,
since I have use the gdalinfo command to test the black
blank tiff.
Markus Metz (et al.) has done quite a bit of work on that module,
hopefully in the latest releases it behaves a bit better for
awkward cases.
for now, check if the GeoTiff actually contains data -- it might
just be the coloring which is misleading but the data is ok.
try:
gdalinfo -stats file.tif
are the Minimum=, Maximum=, and Mean= reasonable values?
2) r.tiff use this command the tiff I got has
not crs (Coordinate System),although I can see the data(the
lines of the road, it is not blank).
And before I export the data,I use the g.region
command to identifier the region.
r.out.tiff has a -t flag which will create a "World File" which
can be used for (numeric) georeferencing. To set a CRS you would
have to use "gdal_translate -a_srs".
also d.out.file can create geotiffs, but it is a rather
different animal than the r.out.* modules so read the help
page carefully.
Hamish