Hi all,
This is my annual wake-up got to do something with rasters and forgot
the finer details of the last time I did a problem similar to it.
I have a bunch of LandSat mrsid imagery, they are in multiple UTM zone
projections and I want to convert them to geographic projection,
WGS84, and into tiff files. The files are too large to convert into a
single tif, so I plan to quarter each file into 4 pieces.
So I wrote a script the reads the files and collects info about them,
then generates 4 gdalwarp commands to reproject each quarter of the
file (perl included below). A typical command looks like:
gdalwarp -srcnodata 0 -dstnodata 0 -s_srs +init=epsg:32642 -t_srs
EPSG:4326 -te 68.9999676729652 24.9707453133203 72.7715338115736
27.4799559407707 -rb -wm 250 --config GDAL_ONE_BIG_READ ON -co
"TILED=YES" ./GeoCover2000/n-42-25.sid ./af/n-42-25_1-0.tif
The reprojection seems to have worked fine, but the bounds seem to be
off because of the black (nodata) areas.
You can see my poor results here:
http://imaptools.com/downloads/raster.gif
Is there a better way to do this? I seem to remember a tool to
generate tiles.
Does this need to be done in two steps? How?
Did I mess up my logic below? I've been over it multiple times and do
not see any errors.
Any help would be appreciated.
Thanks,
-Steve
$ gdalinfo -nomd ./GeoCover2000/n-42-25.sid
Driver: MrSID/Multi-resolution Seamless Image Database (MrSID)
Files: ./GeoCover2000/n-42-25.sid
Size is 51078, 39090
Coordinate System is `'
Origin = (136066.125000000000000,3323577.375000000000000)
Pixel Size = (14.250000000000000,-14.250000000000000)
Corner Coordinates:
Upper Left ( 136066.125, 3323577.375)
Lower Left ( 136066.125, 2766544.875)
Upper Right ( 863927.625, 3323577.375)
Lower Right ( 863927.625, 2766544.875)
Center ( 499996.875, 3045061.125)
Band 1 Block=1024x128 Type=Byte, ColorInterp=Red
Minimum=0.000, Maximum=226.000, Mean=109.610, StdDev=39.202
Overviews: 25539x19545, 12770x9773, 6385x4887, 3193x2444, 1597x1222,
799x611, 400x306, 200x153
Band 2 Block=1024x128 Type=Byte, ColorInterp=Green
Minimum=0.000, Maximum=229.000, Mean=125.833, StdDev=31.828
Overviews: 25539x19545, 12770x9773, 6385x4887, 3193x2444, 1597x1222,
799x611, 400x306, 200x153
Band 3 Block=1024x128 Type=Byte, ColorInterp=Blue
Minimum=0.000, Maximum=227.000, Mean=107.092, StdDev=37.230
Overviews: 25539x19545, 12770x9773, 6385x4887, 3193x2444, 1597x1222,
799x611, 400x306, 200x153
$ cat ./GeoCover2000/n-42-25.prj
Projection UTM
Datum WGS84
Zunits NO
Units METERS
Zone 42
Xshift 0.000000
Yshift 0.000000
Parameters
Perl snippet:
foreach my $sid (@files) {
next unless $wanted && $sid =~ /$wanted/i;
if (! -r $sid) {
warn "SKIPPING: $sid is not readable!\n";
next;
}
my $gdalinfo = `gdalinfo -nomd $sid`;
# parse out the strings that we need
$gdalinfo =~ /Upper Left \((\s*[^,]+),\s*([^\)]+)/s || warn
"Upper Left parse error\n";
my $ul = [$1, $2];
$gdalinfo =~ /Lower Left \((\s*[^,]+),\s*([^\)]+)/s || warn
"Lower Left parse error\n";
my $ll = [$1, $2];
$gdalinfo =~ /Upper Right \((\s*[^,]+),\s*([^\)]+)/s || warn
"Upper Right error\n";
my $ur = [$1, $2];
$gdalinfo =~ /Lower Right \((\s*[^,]+),\s*([^\)]+)/s || warn
"Lower Right error\n";
my $lr = [$1, $2];
my $outf = $sid;
$outf =~ s/\.sid//;
$outf =~ m/\/([^\/]+)$/;
$outf = $1;
my $prj = $sid;
$prj =~ s/\.sid/.prj/;
if (! -r $prj) {
warn "SKIPPING: $prj is not readable!\n";
next;
}
my $projinfo = `grep Zone $prj`;
if ($projinfo =~ /^Zone\s*([-+]?\d+)/) {
my $znum = $1;
if ($znum < 0) {
$epsg = 32700 - $znum;
} else {
$epsg = 32600 + $znum;
}
}
else {
warn "SKIPPING: could not find zone or epsg in $prj\n";
next;
}
my $proj = sprintf("+init=epsg:%d", $epsg);
print "Using projection: $proj for $projinfo" if $DEBUG;
my $pj = Geo::Proj4->new($proj);
if (! $pj) {
warn "SKIPPING: Geo::Proj4 error: " . Geo::Proj4->error .
"\n";
next;
}
$ul = [reverse $pj->inverse(@$ul)];
$ll = [reverse $pj->inverse(@$ll)];
$ur = [reverse $pj->inverse(@$ur)];
$lr = [reverse $pj->inverse(@$lr)];
# this is probably a parallelgram in latlong
if ($DEBUG) {
printf("ul = %11.6f, %11.6f\n", @$ul);
printf("ll = %11.6f, %11.6f\n", @$ll);
printf("ur = %11.6f, %11.6f\n", @$ur);
printf("lr = %11.6f, %11.6f\n", @$lr);
}
# Get the bbox of the parallelgram
my $xmin = $ul->[0]<$ll->[0]?$ul->[0]:$ll->[0];
my $xmax = $ur->[0]>$lr->[0]?$ur->[0]:$lr->[0];
my $ymin = $ll->[1]<$lr->[1]?$ll->[1]:$lr->[1];
my $ymax = $ul->[1]>$ur->[1]?$ul->[1]:$ur->[1];
my $tiled = '-co "TILED=YES"';
$tiled = '' if -e $outf;
my $nparts = 2;
my $dx = ($xmax - $xmin) / $nparts;
my $dy = ($ymax - $ymin) / $nparts;
my ($x0, $x1, $y0, $y1);
for (my $i=0, $x0=$xmin; $i<$nparts; $i++, $x0 += $dx) {
$x1 = $x0 + $dx;
for (my $j=0, $y0=$ymin; $j<$nparts; $j++, $y0 += $dy) {
$y1 = $y0 + $dy;
my $tif = sprintf("%s/%s/%s_%d-%d.tif", $work, $outd,
$outf, $i, $j);
my $cmd = sprintf("gdalwarp -srcnodata 0 -dstnodata 0
-s_srs +init=epsg:%d -t_srs EPSG:4326 -te $x0 $y0 $x1 $y1 -rb -wm 250
--config GDAL_ONE_BIG_READ ON $tiled $sid $tif\n", $epsg);
print "$cmd\n";
my $rc = system($cmd);
print "SYSTEM returned: " . sprintf("%lx\n", ($rc &
0xffff))
if $DEBUG
}
}
}
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