[gdal-dev] ReadAsArray misbehaving...

[Riaan van den Dool]

Thanks for the suggestion.

I have tried:

tileRaster = self.raster.ReadAsArray(xoff=offsetX,  yoff=offsetY,
win_xsize=width,  win_ysize=height)

and

tileRaster = self.raster.ReadAsArray(xoff=offsetX,  yoff=offsetY,
buf_xsize=width,  buf_ysize=height)

but the result is something like:

(array([], shape=(0, 1024), dtype=float32), 0, 0, 1024, 0)


Riaan

On Fri, Sep 3, 2010 at 1:33 PM, Chaitanya kumar CH
<chaitanya.ch at gmail.com>wrote:

> Riaan,
>
> Try calling the method as below
> tileRaster = self.raster.ReadAsArray(xoff=offsetX,  yoff=offsetY,
> xsize=width,  ysize=height)
>
> On Fri, Sep 3, 2010 at 4:09 PM, Riaan van den Dool <riaanvddool at gmail.com>wrote:
>
>> I have recently started a new open-source project that will use gdal
>> extensively, named scikits.eartho.
>>
>> The vision is to implement some advanced algorithms and ideas that we
>> develop and work with at the South African Satellite Applications Centre
>> (SAC) for use in Python (SciPy).
>>
>> I am experiencing some trouble with RasterBand.ReadAsArray.
>>
>> My python code:
>>
>> import osgeo.gdal as gdal
>>
>> class RasterReaderWriter:
>>     def __init__(self,  raster):
>>         self.raster = raster
>>         self.tileWidth =1024
>>         self.tileHeight = 1024
>>         self.tileNum = 0
>>
>>     def setTileSize(self,  width,  height):
>>         self.tileWidth =width
>>         self.tileHeight = height
>>
>>     def resetIterator(self):
>>         self.tileNum = 0
>>
>>     def readNextTile(self):
>>         tileRaster,  offsetX,  offsetY,  width,  height  =
>> self.readTile(self.tileNum)
>>         self.tileNum = self.tileNum + 1
>>         return tileRaster,  offsetX,  offsetY,  width,  height
>>
>>     def readTile(self,  tileNum):
>>         tilesInWidth = self.raster.XSize / self.tileWidth + 1
>>         offsetX = tileNum % tilesInWidth * self.tileWidth
>>         offsetY = tileNum / tilesInWidth * self.tileHeight
>>         width = min(self.tileWidth,  self.raster.XSize - offsetX)
>>         height = min(self.tileHeight,  self.raster.YSize - offsetY)
>>         print offsetX,  offsetY,  width,  height
>>         tileRaster = self.raster.ReadAsArray(offsetX,  offsetY, width,
>> height)
>>         return tileRaster,  offsetX,  offsetY,  width,  height
>>
>>
>>
>>
>> reader = RasterReaderWriter(gdal.Open(iFilename).GetRasterBand(1))
>> print reader.raster.XSize
>> print reader.raster.YSize
>> tile, offsetX, offsetY, width, height = reader.readNextTile()
>>
>> Before the call to readNextTile() the raster XSize and YSize is correct.
>> After the call the raster seems to have been corrupted as the XSize and
>> YSize have invalid values.
>>
>> Any help would be appreciated!
>>
>> Riaan
>>
>> _______________________________________________
>> gdal-dev mailing list
>> gdal-dev at lists.osgeo.org
>> http://lists.osgeo.org/mailman/listinfo/gdal-dev
>>
>
>
>
> --
> Best regards,
> Chaitanya kumar CH.
> /tʃaɪθənjə/ /kʊmɑr/
> +91-9494447584
> 17.2416N 80.1426E
>
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