Re: [GRASS-user] Re: GRASS-user] Help with reprojection (Hamish)

[Alex Bernstein]

Thanks everyone for trying to help. A few hours ago, I've finally
accomplished what I needed by using gdalwarp directly. I had some
trouble with it as well, because it couldn't handle the reprojection
of a global image. But once I limited it to the region of interest, it
worked,

Thanks again,
--Alex
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[GRASS-user] Help with reprojection

[Alex Bernstein]

Hi,

I'm new to GRASS, and am having trouble with reprojection. I've spent
two days trying to figure this out, and I feel that I'm close, but
reprojection is still failing. Could anyone clue me in what I'm
missing?

The input data set is Natural Earth II map of the world
http://www.nacis.org/data/NE2/NE2_WDB1.jpg 16200x8100 JPG in plate
carrée projection. I need to reproject it into Lambert azimuthal
equal-area projection centered on N0 E15. I'm using WinGRASS 6.3.0.

First, I've created GRASS location geographic with following region
and projection:

 g.region -p
projection: 99 (Equidistant Cylindrical (Plate Caree))
zone:   0
datum:  wgs84
ellipsoid:  wgs84
north:  8100
south:  0
west:   0
east:   16200
nsres:  1
ewres:  1
rows:   8100
cols:   16200
cells:  13122

 g.proj -p datumtrans=0
PROJ_INFO-
name   : Equidistant Cylindrical (Plate Caree)
datum  : wgs84
towgs84: 0.000,0.000,0.000
proj   : eqc
ellps  : wgs84
a  : 6378137.00
es : 0.0066943800
f  : 298.2572235630
lat_0  : 0.00
lat_ts : 0.00
lon_0  : 0.00
-PROJ_UNITS
unit   : meter
units  : meters
meters : 1.0

I then imported the JPG map, which got split into color channels and
composed the channels together into single map.

After, I created a new location lambert:
 g.region -p
projection: 99 (Lambert Azimuthal Equal Area)
zone:   0
datum:  wgs84
ellipsoid:  wgs84
north:  8100
south:  0
west:   0
east:   16200
nsres:  1
ewres:  1
rows:   8100
cols:   16200
cells:  13122

 g.proj -p datumtrans=0
-PROJ_INFO-
name   : Lambert Azimuthal Equal Area
datum  : wgs84
towgs84: 0.000,0.000,0.000
proj   : laea
ellps  : wgs84
a  : 6378137.00
es : 0.0066943800
f  : 298.2572235630
lat_0  : 0.00
lon_0  : 15.00
x_0: 0.00
y_0: 0.00
-PROJ_UNITS
unit   : meter
units  : meters
meters : 1.0

Finally, when I try reprojection I get Input raster map is outside
current region error:
 r.proj input=NE2 location=geographic mapset=PERMANENT method=cubic
Input Projection Parameters:  +proj=eqc +lat_0=0.00
+lat_ts=0.00 +lon_0=0.00 +a=6378137 +rf=298.257223563
+no_defs +towgs84=0.000,0.000,0.000
Input Unit Factor: 1
Output Projection Parameters:  +proj=laea +lat_0=0.00
+lon_0=15.00 +x_0=0.00 +y_0=0.00 +a=6378137
+rf=298.257223563 +no_defs +towgs84=0.000,0.000,0.000
Output Unit Factor: 1
Input raster map is outside current region

How can I make this work?
Thanks,
Alex
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