[gdal-dev] numpy array to raster

[Frank Warmerdam]

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,
-- 
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