[GRASS-user] what is requried when import data to grass?

Markus GRASS markus.metz.giswork at googlemail.com
Mon Jun 15 06:21:11 EDT 2009

maven apache wrote:
> Can I understand the difference as the difference between the geotiff
> and the tiff?
No. A geotiff can be a tiff with georeferencing information (projection,
extends, resolution). The difference between r.out.tiff output and
r.out.gdal output is what kind of information is exported: color rules
for r.out.tiff, cell values for r.out.gdal. As an example, use some
elevation data in one of the sample datasets, set different color rules,
export each time with r.out.tiff and with r.out.gdal. r.out.tiff output
(pixel values) is dependent on the current color rules, r.out.gdal
output (pixel values) stays the same (as long as you don't change the
region), but the embedded color table may change.

> 2009/6/15 Markus GRASS <markus.metz.giswork at googlemail.com
> <mailto:markus.metz.giswork at googlemail.com>>
>     Micha Silver wrote:
>     > As far as I know, r.out.tiff is just a simplified version of
>     r.out.gdal.
>     No.
>     r.out.tiff exports an image that looks like what you see in the
>     display,
>     in other words, it translates the color rules of a GRASS raster to a
>     tiff image. The cell values of the GRASS raster are *not* exported by
>     r.out.tiff.
>     r.out.gdal exports raster data (cell values) and, when possible,
>     embeds
>     color rules in the metadata. The exported data may or may not look
>     like
>     the GRASS display of the raster, depending on the data type and file
>     format choosen for export and the capabilities of the spatial data
>     viewer used to display the exported data.
>     Markus M
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