Dear All,
I’ve imported a .PNG file with r.in.gdal (i.e. map.png) in order to make a georeferencing file. The importing procedure returned 3 files: map.red, map.green, map.blue. I don’t know how continue to reach my goal.
Thanks in advance
Edmondo
On 09/04/08 11:17, Edmondo Elisei wrote:
Dear All,
I've imported a .PNG file with r.in.gdal (i.e. map.png) in order to make a georeferencing file. The importing procedure returned 3 files: map.red, map.green, map.blue. I don't know how continue to reach my goal.
For most raster analyses using the three separate bands is better. You can visualise them with d.rgp. However, if it is the original combined image you are interested in, you can recreate this with r.composite.
Moritz
Edmondo Elisei wrote:
> I've imported a .PNG file with r.in.gdal (i.e. map.png) in order to
> make a georeferencing file. The importing procedure returned 3 files:
> map.red, map.green, map.blue. I don't know how continue to reach my
> goal.
Moritz:
For most raster analyses using the three separate bands is better. You
can visualise them with d.rgp. However, if it is the original combined
image you are interested in, you can recreate this with r.composite.
[d.rgb]
also, r.in.gdal will load those as bands into a group (g.list group), and
when you set ground control points (GCPs) with the GUI georeferencing
tool or i.points/i.vpoints, you can then use those points to georectify
all bands in a single command (i.rectify). If you just wish apply
geocoding to the file, either 1) create a .tfw "world file" by hand, 2)
use 'gdal_translate -a_ullr' to make a GeoTiff with that info, or 3) in
GRASS use r.region to name the outside edges and map resolution.
Hamish
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