[GRASS-user] Warning regarding Datum unknown not recognised by GRASS

[Kim Besson]

Greetings

A couple of days ago I have exchanged a few messages with Paul Kelly and
Micha Silver regarding this issue. But now I have a new example and I want
to know if I'm doing anything wrong and better understand what is  GRASS
behaviour.

I'm trying to have an aumatic procedure to reproject images using gdalwarp.
First it checks image CRS (g.proj input=IMAGE -jf) and compares with
Location's CRS (g.proj -jf).

As target_CRS I'm using the output from g.proj -j -f .
In this case, g.proj -jf give me the Location«s CRS:
+proj=utm +south +no_defs +zone=24 +a=6378137 +rf=298.257223563
+towgs84=0.000,0.000,0.000 +to_meter=1
(Sidenote. This Location was created based on an EPSG)

I use this expression to warp the image:
gdalwarp -t_srs "+proj=utm +south +no_defs +zone=24 +a=6378137
+rf=298.257223563 +towgs84=0.000,0.000,0.000 +to_meter=1" input.tif
proj4.tif

But if I check proj4.tif CRS I get this:
+proj=utm +south +no_defs +zone=24 +a=6378137 +rf=298.257223563 +to_meter=1
Trying to open with OGR...
Trying to open with GDAL...
...succeeded.
Datum <unknown> not recognised by GRASS and no parameters found

Why towgs84 is not kept in the image?

THanks

Kim
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