Using no data values during tiling

[Alex M. Hamer]

Hi,

I am currently attempting to tile an image I have masked and populated image stats for using imageutils.maskImage and imageutils.popImageStats. However, the no data value I set in popImageStats is being ignored when I use imageutils.createTiles it tiles the no data values as if they were data values.

Is there a way to set a no data value within createTiles so no data values are displayed as no data values during tiling?

Regards,
Alex

[Pete Bunting [pfb]]

Dear Alex, 

I don’t get want you are trying to do here… 

Create tiles will only split the image using the whole image dimensions - is doesn’t do anything with the pixel values other than copy them into the new tile images. 

If you want to create tiles which gave a minimum proportion of valid data you can use the following functions to create a shapefile with polygons defining the tiles and then use the second function to cut out the tiles. 

rsgislib.imageutils.tilingutils.createMinDataTiles(inputImage, outshp, outclumpsFile, width, height, validDataThreshold, maskIntersect=None, offset=False, force=True, tmpdir=’tilestemp’)

rsgislib.imageutils.tilingutils.createTileMaskImagesFromShp(inputImage, tileShp, tilesNameBase, tilesMaskDIR, tmpdir=’tilestemp’, imgFormat=’KEA’)

Best wishes, 

Pete

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* Dr Pete Bunting
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[Pete Bunting [pfb]]

Hi Alex, 

It do you know which shapefile it is failing on? Does it have any valid data? Does it fail if you just run that one separately? 

Best wishes, 

Pete

****************************************************
* Dr Pete Bunting
* Reader in Remote Sensing
* Earth Observation and Ecosystem Dynamics Group
* Department of Geography and Earth Sciences
* Aberystwyth University
* Aberystwyth
* Ceredigion
* SY23 3DB
* UK
* 
* Ph: +44 (0) 1970 622615
* Mob: +44 (0) 7917 842743
* Email: p...@aber.ac.uk
* ORCID: http://orcid.org/0000-0002-7435-0148
****************************************************

"Please consider the environment before printing this email or any documents attached”

On 21 Aug 2017, at 17:12, Alex M. Hamer <alexm...@outlook.com> wrote:

Hi Pete,

I have created the shapefile defining the tiles for my image, however when I use the createTileMaskImagesFromShp() it creates all of the tiles as shp files in the temporary directory and begins to rasterise each one until I get the following error after ~500 tiles:

 File "min_tile.py", line 11, in <module>
    imageutils.tilingutils.createTileMaskImagesFromShp(VVsubImg, shp, tilesImgBase, tilesMaskDIR, tmpdir, imgFormat='KEA')
  File "/home/student/miniconda3/envs/exampkgs/lib/python3.5/site-packages/rsgislib/imageutils/tilingutils.py", line 207, in createTileMaskImagesFromShp
    vectorutils.rasterise2Image(shpFile, inputImage, imgTileFile, imgFormat, shpAtt=None, shpExt=True)
  File "/home/student/miniconda3/envs/exampkgs/lib/python3.5/site-packages/rsgislib/vectorutils/__init__.py", line 96, in rasterise2Image
    raise e
  File "/home/student/miniconda3/envs/exampkgs/lib/python3.5/site-packages/rsgislib/vectorutils/__init__.py", line 73, in rasterise2Image
    inVectorLayer = inVectorDS.GetLayer(0)
AttributeError: 'NoneType' object has no attribute 'GetLayer'

Regards,
Alex

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