On 07/29/2014 04:04 PM, Cleo Drakos wrote:
Thanks for your response.
I tried the followings:
gcalc = 'C:\\Users\\cleo\\Documents\\gdalpys\\gdal_calc.py'
##I produced second file (b)as the copy of first(a)
a = 'D:\\a.tif'
b = 'D:\\b.tif'
outfile = 'D:\\result.tif'
expr = '(A-B)/(A+B)'
subprocess.call([sys.executable,gcalc,'-A',a,'--A_band','1','-B',b,'--B_band','0','--outfile',outfile,\
'--calc',expr,'--type','Float32','--format','ENVI'],shell=True)
a,b,outfile = None, None,None
Unfortunately, resulted file is completely black.
I hope someone can help me.
I don't use gdal_calc myself, but I suppose the problem is the byte
datatype. I would try to convert the input data to float32 first (use
gdal_translate -ot Float32) and try again.
Best,
Vincent.
On Tue, Jul 29, 2014 at 10:37 PM, Etienne Tourigny
<etourigny....@gmail.com <mailto:etourigny....@gmail.com>> wrote:
I am not sure, but you can do the following to make sure:
cp infile infile2
gdal_calc.py -A infile --A_band 1 -B infile2 --B_band 0 --outfile
outfile --calc "(A-B)/(A+B)"
Also, perhaps the extra comma in your command might be to blame
"-B infile,"
Etienne
On Tue, Jul 29, 2014 at 3:46 AM, Cleo Drakos
<cleo21dra...@gmail.com <mailto:cleo21dra...@gmail.com>> wrote:
Hi GDAL Developers,
I have one GeoTIFF file with 2 bands. The data type is Byte. I
want to calculate (Band2-Band1)/(Band2+Band1).
But the following command provided a dark image:
gdal_calc.py -A infile --A_band 1 -B infile, --B_band 0
--outfile outfile --calc "(A-B)/(A+B)"
Does gdal_calc.py not calculate arithmetic with in the same file?
Thanks for your time.
cleo
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