[GRASS-user] r.proj

I am trying to re-project some landsat 8 bands in from one location into another location with the same Ordnance Survey Projection (epsg:27700) using r.proj. They should overlap but currently do not. Am i using the correct module? The error message is:


(Tue Apr 29 11:30:48 2014)
r.proj input=LC82040242013363LGN00_refl1 location=Landsat8 mapset=Landsat dbase=\msastore\decsgroup\GIS Admin support share output=LC82040242013363LGN00_refl1
Input Projection Parameters: +proj=tmerc +lat_0=23
+lon_0=-96 +k=1 +x_0=0 +y_0=0 +no_defs +a=6377563.396
+rf=299.3249646 +towgs84=368.000,-120.000,425.000
Input Unit Factor: 1
Output Projection Parameters: +proj=tmerc +lat_0=49
+lon_0=-2 +k=0.9996012717 +x_0=400000 +y_0=-100000 +no_defs
+a=6377563.396 +rf=299.3249646
+towgs84=368.000,-120.000,425.000
Output Unit Factor: 1
WARNING: pj_transform() failed: latitude or longitude exceeded limits
WARNING: pj_transform() failed: latitude or longitude exceeded limits
WARNING: pj_transform() failed: latitude or longitude exceeded limits

r.proj parameters

From Projection

projection: 99 (Transverse Mercator)
zone: 0
datum: osgb36
ellipsoid: airy
north: 5848830
south: 5605470
west: 296070
east: 536430
nsres: 30
ewres: 30
rows: 8112
cols: 8012
cells: 64993344

to Projection

projection: 99 (Transverse Mercator)
zone: 0
datum: osgb36
ellipsoid: airy
north: 1230000
south: 0
west: 0
east: 660000
nsres: 50
ewres: 50
rows: 24600
cols: 13200
cells: 324720000

Paul J. Shapley

On Tue, Apr 29, 2014 at 1:22 PM, Paul Shapley <p.shapley@gmail.com> wrote:

I am trying to re-project some landsat 8 bands in from one location into
another location with the same Ordnance Survey Projection (epsg:27700) using
r.proj.

Why do you use r.proj here? If the projection in the two locations are
the same then you only introduce artifacts. To transfer data between
locations with identical projection simply use r.pack and r.unpack:

http://grass.osgeo.org/grass70/manuals/r.pack.html
http://grass.osgeo.org/grass70/manuals/r.unpack.html

(likewise for GRASS 6.4.x).

Markus