On Nov 22, 2011, at 3:08 PM, David Mertens wrote:
> On Tue, Nov 22, 2011 at 1:06 PM, Puneet Kishor <[email protected]> wrote:
>
>> Greetings,
>>
>> Is it possible to read .bil files with PDL? readenvi at
>> http://cpansearch.perl.org/src/CHM/PDL-2.4.9/IO/ENVI/readenvi.pdl seems
>> promising, but I wasn't able to test with it because it had "too many
>> errors" when trying to run it.
>>
>> I am hoping to dissect a few climate data grids that I downloaded from
>> http://www.worldclim.org/
>>
>>
>> --
>> Puneet Kishor
>> _______________________________________________
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>> http://mailman.jach.hawaii.edu/mailman/listinfo/perldl
>>
>
> I'd never heard of this IO module and figured I should look into who added
> it. You're in luck: this was committed by The Pumpking (i.e. Chris
> Marshall), certainly not a one-time committer. :-)
>
> While I'm sure Chris will answer you soon, he would probably appreciate if
> you pasted the errors that you get and, especially, the version of PDL that
> you're using. It looks like he updated this last during the development
> cycle that lead to PDL 2.4.8. Do you have 2.4.8 or 2.4.9, or an earlier
> version?
I am using PDL 2.4.6, because that is the latest version available at this time
via macports. I am trying to figure out how to upgrade that to 2.4.9, but that
is a different project. In any case, I don't think the PDL version is the issue
here. With regards to the error in readenvi.pl it was just a typo, on line 145
> if eof($hdrfile) {
should read
> if (eof($hdrfile)) {
It seems to me that I can possibly use that file as a template to write a new
program for reading these Worldclim files which are very simple .bil files.
They do have a header file, but it is not the kind of header that FlexRaw (or
FastRaw) expects. Here is a typical header
BYTEORDER I
LAYOUT BIL
NROWS 18000
NCOLS 43200
NBANDS 1
NBITS 16
BANDROWBYTES 86400
TOTALROWBYTES 86400
BANDGAPBYTES 0
NODATA -9999
ULXMAP -179.995833333333333
ULYMAP 89.995833333333333
XDIM 0.008333333333333333
YDIM 0.008333333333333333
DatabaseName WorldClim
Version 1.4
Release 3
Created 20051226
Projection GEOGRAPHIC
Datum WGS84
MinX -180
MaxX 180
MinY -60
MaxY 90
MinValue -258
MaxValue 316
Variable tmin
month September
Units deg C * 10
I have to figure out what information to extract from the above to create a
FlexRaw compatible header the way readenvi.pl does, but am a loss for now. I
have tried something like the following, but with no luck
byte
3
43200 18000 1
>
> David
>
> --
> Sent via my carrier pigeon.
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