On Tue, Aug 31, 2010 at 11:59 AM, P Kishor <[email protected]> wrote:
> On Tue, Aug 31, 2010 at 11:54 AM, Chris Marshall <[email protected]> wrote:
>>> I would love to learn that I am doing something stupid,
>>> but I am fairly convinced that there is either a bug or
>>> an untrapped error in the PDL code.
>>
>> Actually the error is being trapped which is what
>> you have reported. The problem is that you have
>> bad values in the image data that you are trying
>> to save.
>>
>> If there is a problem with the current PDL
>> code, it may be that an error is *not* being given
>> for the non-LUT wpic() case.
>>
>> At any rate, the fix is to save image data *without*
>> bad values in them. I suggest using setbadtoval()
>> and then make that value in your color map special
>> (e.g., bright red so you can see the erroneous pixels).
>>
>
> I don't even know which value is bad? If I can't see it, if I don't
> know which one it is, if I can't even list it out, how do I know which
> one to setbadtoval()?
>
> I already have set -9999 to bad, as those are pixels with no data. I
> used to have NaNs, and I have gotten rid of those. Now, as far as I
> can tell, I have either -9999, or I have a valid number.
>
> When I write the entire piddle to a b&w image, it writes fine. When I
> try to use a LUT, all hell breaks loose.
>
> as you say, I should use "setbadtoval() and then make that value in
> your color map special." What is "that value"? That is what I am
> trying to determine.
>
>
Assuming that something might be wrong with the BAD values in my
piddles, I did the following --
# Set the bad value for the piddle and turn on the badflag
$pdl->badvalue(-9999.0);
$pdl->badflag(1);
# Multiply each value by 10
$pdl = $pdl * 10;
pdl_info('pdl', $pdl);
# Get the min max
my ($min, $max) = $pdl->minmax;
my $div = int(($max - $min) / 10) + 1;
# Grab a piddle for one year, and flip the piddle to correct "video coords"
my $ypdl = $pdl->slice(":,:,0")->squeeze()->slice(':,-1:0:-1');
# Place each element of the pdl into a corresponding bin and convert to byte
$ypdl = byte(floor ($ypdl / $div));
pdl_info('ypdl', $ypdl);
# Create a lookup table ########
my $lut = get_lut();
pdl_info('lut', $lut);
# Replicate ImageRGB.pm code
my $foo = byte($lut->xchg(0,1));
pdl_info('foo', $foo);
my $bar = $ypdl->dummy(0);
pdl_info('bar', $bar);
my $res = index($foo, $bar);
pdl_info('res', $res);
print bigstring($res,"%3g") . "\n";
sub pdl_info {
my ($name, $pdl) = @_;
print "\n";
print "State of bad flag in piddle $name: " .
$pdl->check_badflag . "\n";
print "The bad value for piddle $name is: " . $pdl->badvalue() . "\n";
print " Info for piddle $name: " . $pdl->info . "\n";
print "-" x 50 . "\n";
}
sub get_lut {
my $lut = byte(zeroes 3, 256);
# Increment red from 0 to 255
my $r = $lut->slice('0,:');
$r .= $r + $r->yvals;
# Set green to 255
my $g = $lut->slice('1,:');
$g .= $g + 255;
return $lut;
}
sub bigstring {
my($pdl, $fmt, $lev) = @_;
$fmt = "%g" unless($fmt);
my $s=" "x$lev;
if($pdl->ndims > 1) {
$s .= join("\n", "[", (map { bigstring($_,$fmt,$lev+1)
} dog $pdl), $s."]");
}
elsif ($pdl->ndims) {
$s .= "[ " . join(" ",map { sprintf($fmt,$_) }
$pdl->list) . " ]";
}
else {
$s = sprintf($fmt,$pdl->at(0));
}
return $s;
}
This is what printed out
punk...@hardangervidda ~/Data/carbonmodel/cnnf$perl testindex.pl
State of bad flag in piddle pdl: 1
The bad value for piddle pdl is: -9999
Info for piddle pdl: PDL: Float D [252,189,100]
--------------------------------------------------
State of bad flag in piddle ypdl: 1
The bad value for piddle ypdl is: 255
Info for piddle ypdl: PDL: Byte D [252,189]
--------------------------------------------------
State of bad flag in piddle lut: 0
The bad value for piddle lut is: 255
Info for piddle lut: PDL: Byte D [3,256]
--------------------------------------------------
State of bad flag in piddle foo: 0
The bad value for piddle foo is: 255
Info for piddle foo: PDL: Byte D [256,3]
--------------------------------------------------
State of bad flag in piddle bar: 1
The bad value for piddle bar is: 255
Info for piddle bar: PDL: Byte D [1,252,189]
--------------------------------------------------
PDL::index: invalid index -2147483648 (valid range 0..255) at
/usr/local/lib/perl5/site_perl/5.12.1/darwin-2level/PDL/Bad.pm line
493.
--
Puneet Kishor http://www.punkish.org
Carbon Model http://carbonmodel.org
Charter Member, Open Source Geospatial Foundation http://www.osgeo.org
Science Commons Fellow, http://sciencecommons.org/about/whoweare/kishor
Nelson Institute, UW-Madison http://www.nelson.wisc.edu
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