[gdal-dev] numpy array to raster

[questions anon]

no I quickly checked that!
myarray is:
[[ 16.15035553  16.14380074  16.15581551 ...,  18.06388149  18.08930645
   18.08825245]
 [ 16.2154911   16.21180592  16.23977184 ...,  18.1085537   18.12040272
   18.12342682]
 [ 16.32851467  16.29202938  16.28964043 ...,  18.16753635  18.14905453
   18.16632977]
 ...,
 [ 30.50812759  30.58384018  30.66707535 ...,  26.31020527  26.47789459
   27.11495361]
 [ 30.76499577  30.76497536  30.79138317 ...,  26.45928288  26.64059887
   27.03641129]
 [ 31.01263275  30.96269417  30.9933857  ...,  26.78247185  26.77845631
   26.97975636]]

On Wed, Feb 1, 2012 at 1:25 PM, Kyle Shannon <ksshannon at gmail.com> wrote:

> Is 'myarray' full of zeros?
>
> /**
>  *
>  * Kyle Shannon
>  * ksshannon at gmail.com
>  *
>  */
>
>
>
> On Tue, Jan 31, 2012 at 19:20, questions anon <questions.anon at gmail.com>wrote:
>
>> thanks Frank, following your instructions with:
>>
>> src_ds=gdal_array.OpenArray(myarray)
>> dst_ds =
>> gdal.GetDriverByName('GTiff').Create('E:/test/rasterise/mynewraster.tif',ncols,
>> nrows, 1 ,gdal.GDT_Byte)
>>  dst_ds.SetGeoTransform(geotransform)
>> dst_ds.GetRasterBand(1).WriteArray(myarray)
>>
>> I do not receive any error messages but the tiff produced are all just
>> zeros. Is there a step I am missing?
>> thanks
>>
>>
>> On Wed, Feb 1, 2012 at 12:07 PM, Frank Warmerdam <warmerdam at pobox.com>wrote:
>>
>>> On Tue, Jan 31, 2012 at 4:38 PM, questions anon
>>> <questions.anon at gmail.com> wrote:
>>> > I need to output my numpy array as a raster so that someone else can
>>> access
>>> > the data in ArcGIS. So basically the steps I need are:
>>> > read numpy array into gdal
>>> > convert to raster
>>> > use latitude and longitude and array size to set projection
>>> >
>>> > I am really struggling with gdal because I can't seem to find enough
>>> > documentation about each step to understand what it is doing.
>>> > Here are some of the steps I think I need:
>>> >
>>> > myarray=myarray
>>> > #the extent and shape of my array
>>> > xmin,ymin,xmax,ymax=[139.8,-39.2,150.0,-33.6]
>>> > ncols,nrows=[193,106]
>>> > xres=(xmax-xmin)/float(ncols)
>>> > yres=(ymax-ymin)/float(nrows)
>>> > geotransform=(xmin,xres,0,ymax,0, -yres)
>>> >
>>> > from osgeo import gdal
>>> > from osgeo import gdal_array
>>> >
>>> > src_ds=gdal_array.OpenArray(myarray)
>>> >
>>> > dst_ds =
>>> >
>>> gdal.GetDriverByName('GTiff').Create('E:/test/rasterise/mynewraster.tif',ncols,
>>> > nrows, 1 ,gdal.GDT_Byte)
>>> > dst_rb = dst_ds.GetRasterBand(0)
>>> > dst_ds.SetGeoTransform(geotransform)
>>> > output = gdal.RasterizeLayer(dst_ds)
>>>
>>> Dear "Questions Anon",
>>>
>>> There are a variety of Python related information at:
>>>
>>>  http://trac.osgeo.org/gdal/wiki/GdalOgrInPython
>>>
>>> One serious issue with the above is that "gdal.RasterizeLayer()" is used
>>> to
>>> turn vector data into raster data - for instance to rasterize polygon
>>> features
>>> into an existing raster file.  I think you want to write your array into
>>> a
>>> raster file.  I think you can just call "dst_ds.WriteArray(myarray)".
>>>
>>> Alternatively if that method does not exist on the dataset, you
>>> can write the one band like:
>>>
>>>  dst_ds.GetRasterBand(1).WriteArray(myarray)
>>>
>>> Some of the samples referenced from the GdalOgrInPython should be
>>> helpful though I understand it can be hard to know where to look.
>>>
>>> Best regards,
>>> --
>>>
>>> ---------------------------------------+--------------------------------------
>>> I set the clouds in motion - turn up   | Frank Warmerdam,
>>> warmerdam at pobox.com
>>> light and sound - activate the windows | http://pobox.com/~warmerdam
>>> and watch the world go round - Rush    | Geospatial Software Developer
>>>
>>
>>
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