Manipulating Raster Data - Open Source Geospatial Tools: Applications in Earth Observation - page 70

access with the command gdalinfo --formats (look for formats that indicate
rw

+

).

Usage: gdal_edit [--help-general] [-a_srs srs_def] [-a_ullr ulx
ₒ uly lrx lry] [-tr xres yres] [-unsetgt] [-a_nodata value]

ₒ [-gcp pixel line easting northing [elevation]]* [-mo

ₒ

"META-TAG=VALUE"]* datasetname

-nogcp
Suppress ground control points list printing
-a_srs srs_def
Defines the target coordinate system. This coordinate system will be written to
the dataset.
-a_ullr ulx uly lrx lry
Assign/override the georeferenced bounds of the dataset.
-tr xres yres
Set target resolution. The values must be expressed in georeferenced units. Both
must be positive values.
-unsetgt
Remove the georeference information.
-a_nodata value
Assign a specified no-data value to output bands. Can be set to none to remove a
no-data value if one exists for the dataset.
-gcp pixel line easting northing [elevation]
Add the indicated ground control point to the dataset. This optionmay be provided
multiple times to provide a set of GCPs.
-mo "META-TAG=VALUE"
Passes a metadata key and value to set on the output dataset if possible.

The options -a_ullr , -tr and -unsetgt must be used exclusively. It must
be stressed that this utility does not change the actual pixel values of the dataset. To
resample or reproject datasets, different utilities must be used ( gdaltransform
and gdalwarp ). The following example changes the datum to WGS84, the projec-
tion to GEODETIC and the bounding box of a raster dataset. 3

gdal_edit -mo DATUM=WGS84 -mo PROJ=GEODETIC -a_ullr 7 47 8 46
ₒ

test.ecw

3 Described in more detail in the GDAL documentation http://www.gdal.org/gdal_edit.html .