[gdal-dev] Creating Geotiff with WriteArray in Python

[Lucena, Ivan]

Also, remember to check if your GDAL distribution supports Bigtiff if 
the file size is greater than 4GB (13700x13300x32=5,830,720,000 ?).

gaffigan at sfos.uaf.edu wrote:
> Hello, Matt.  I think the array argument to the WriteArray function must
> be 2D.  In your example, nxarray should have shape (1,nx), instead of
> (nx,).  So, on the relevant line, try the following instead:
>   dst_ds.GetRasterBand(1).WriteArray(reshape(nxarray,(1,nx)),0,j)
> 
> Hope this gets you closer.
> 
> Steve
> 
>> Dear GDAL/Python Users,
>>
>> I am struggling to make the following python/GDAL script work. I am
> reading/converting large Palsar images to GeoTiff, and therefore I have
> to be concerned with memory. I believe I have the following script very
> close to working. The problem is related to the line
> "dst_ds.GetRasterBand(1).WriteArray(nxarray,0,j)" - I am trying to write
> an imported integer array(y,x) , 13700x13300, to a tif file row by row
> using a for loop structure as a converted float. I constructed this code
> from found examples, ie, 4bandto3band.py. However,
>> "WriteArray" is giving me trouble.  I believe the problem is something
> very simple; the arguments in WriteArray are not quite right. I am quite
> new to GDAL and Python. Some help would be very much
>> appreciated. Below are the errors I receive and my script.
>> thanks,
>> Matt
>>
>>
>> Traceback (most recent call last):
>>   File "./test.py", line 43, in <module>
>>     dst_ds.GetRasterBand(1).WriteArray(nxarray,0,j)
>>   File "/usr/lib/python2.5/site-packages/gdal.py", line 876, in
> WriteArray
>>     return gdalnumeric.BandWriteArray( self, array, xoff, yoff )
>>   File "/usr/lib/python2.5/site-packages/gdalnumeric.py", line 187, in
>> BandWriteArray
>>     xsize = array.shape[1]
>> IndexError: tuple index out of range
>>
>>
>>
>>
>> #! /usr/bin/env python
>>
>> import Numeric
>> from Numeric import *
>> import pickle, array, sys, os, shutil
>> import gdal, gdalnumeric
>> from gdalconst import *
>> import numpy
>> from math import *
>>
>>
>> file =
>> "china/hangzhou/processed/ALPSRP021230580/IMG-HH-ALPSRP021230580-H1.5GUA"
>>
>> gd=gdal.Open(file)
>> array=gd.ReadAsArray()
>> dims = array.shape
>> nx=dims[1]
>> ny=dims[0]
>>
>> nxarray=zeros(nx,Float)
>> cal_factor=-83.0
>>
>> dst_format = 'GTiff'
>> dst_datatype = gdal.GDT_Float32
>> dst_options = ['COMPRESS=LZW']
>> dst_file='foo.tif'
>> dst_xsize = nx
>> dst_ysize = ny
>> dst_nbands = 1
>>
>> driver = gdal.GetDriverByName( dst_format )
>> dst_ds = driver.Create(dst_file, dst_xsize, dst_ysize, dst_nbands,
> dst_datatype, dst_options)
>>
>> for j in range(0,ny-1):
>>   for i in range(0,nx-1):
>>
>>     nxarray[i]=0.0
>>     tmp = array[j,i] * 1.0
>>     if (tmp > 0):
>>       nxarray[i] = 10.0 * log10(pow(tmp,2)) + cal_factor
>>
>>   dst_ds.GetRasterBand(1).WriteArray(nxarray,0,j)
>>
>> dst_ds = None
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>> gdal-dev at lists.osgeo.org
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>>
> 
> 
> 
> 
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