[GRASSLIST:5777] GRASS Novice Needs Help
John Ronan
jronan at tssg.org
Tue Feb 15 05:48:25 EST 2005
Morning,
I recently came across Grass when I posted on another list asking the
question on how to convert scanned images into georeferenced images
that could be used in xastir (www.xastir.org). So in fact Im not quite
knowledgeable enough to call myself a novice even.
Thus far I've managed to convert the tiffs to unprojected lat/long
rasters that xastir (www.xastir.org) can use and in fairness they seem
to be pretty accurate. This was only possible by the extra-ordinary
patience of Gerry Creager and Tom Russo. Who pretty much walked me
through it step by step, thanks guys.
Anyways my problem now is trying to get rid of the 'fluff' that gets
created around the edges by gdalwarp when it does the 'warping'. I've
been attempting to use r.patch followed by r.proj to reproject the
patched raster into another lat/long database but I've thus far not
been successful.
I'm currently getting the error 'Input map is outside current region',
here are the regions,
Firstly the Irish Grid.
projection: 99 (Transverse Mercator)
zone: 0
datum: ire65
ellipsoid: modif_airy
north: 52.3
south: 52.15
west: -7.4
east: -6.85
nsres: 0.15
ewres: 0.55
rows: 1
cols: 1
The Lat/Long region (bigger than the one above I think)
g.region -p
projection: 3 (Latitude-Longitude)
zone: 0
datum: wgs84
ellipsoid: wgs84
north: 54N
south: 52N
west: 9W
east: 5W
nsres: 0:00:00.187198
ewres: 0:00:00.1872
rows: 38462
cols: 76923
So I've done a r.patch of two 'tiles' in the Irish Grid Database called
ubermap. I exit grass, open it in the 'latlong' location and try to do
r.proj
r.proj input=ubermap location=Ireland mapset=osmaps output=waterford1
method=nearest
Input Projection Parameters: +proj=tmerc +lat_0=53.5000000000
+lon_0=-8.0000000000 +k_0=1.0000350000 +x_0=200000.0000000000
+y_0=250000.0000000000 +a=6377340.189 +rf=299.3249646 +no_defs
+towgs84=482.530,-130.596,564.557,-1.042,-0.214,-0.631,8.15
Input Unit Factor: 1
Output Projection Parameters: +proj=latlong +a=6378137
+rf=298.257223563 +no_defs +towgs84=0.000,0.000,0.000
Output Unit Factor: 1
ERROR: Input map is outside current region
And I'm stuck... as I've really got no idea what I'm doing here any
help would be appreciated.
Regards
de John
EI7IG
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