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Compression not applying when updating/exiting GeoTiff file in GDAL?

0

I have a GeoTiff file with dimensions 300 x 300 and 8760 bands (hourly for one full year). I am testing some code that opens the file, updates ONE band and exits - but I am finding that the file size almost doubles when I exit the file, despite the new band being the same data type etc. Code is as follows:

I am creating the GeoTiff file using the following creation options using many singular GeoTiff files:

gdal_merge.py -separate -co BIGTIFF=YES -co COMPRESS=DEFLATE -co PREDICTOR=1 -co TILED=YES -co BLOCKXSIZE=64 -co BLOCKYSIZE=64 -o block64.tif *.tif

The file size is 947MB.

I am then updating the file using the following code:

ds = gdal.Open("block64.tif", gdal.GA_Update) 

# Some simple operation to change band values
arr = ds.GetRasterBand(11).ReadAsArray() / 2
ds.GetRasterBand(11).WriteArray(arr)
ds.FlushCache()
ds = None

The file size is now 1.9GB.

My preliminary conclusion is that the compression/creation options are not being applied once I've updated and exited the file. Is there any way to re-compress/reapply the options once I close the file?

gdal geotiff-tiff compression bigtiff

share|improve this question

edited yesterday

PolyGeo♦

53.8k1781245

asked yesterday

tdatda

221214

• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  Compressed tiff is not optimal for updating but doubled size feels too much. Perhaps you could try something similar to the create vrt route in this wiki document trac.osgeo.org/gdal/wiki/UserDocs/…. If you do not get help from gis.stackexchange you should write and ask from the gdal-dev mailing list.
  
  – user30184
  yesterday
  

  
  
  
  


• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  More of a workaround than a real answer, but you could read all of the bands, remove the file, and recreate it with your updates.
  
  – mikewatt
  21 hours ago
  
  

  
  
  
  


• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  I could... and that's the answer I've come up with so far, but I'm trying to make the process as quick as possible and rewriting large files takes time (I'm updating files server-side and need to be quick to not impact client-side I/O requests).
  
  – tda
  11 hours ago
  

  
  
  
  

add a comment | 

0

I have a GeoTiff file with dimensions 300 x 300 and 8760 bands (hourly for one full year). I am testing some code that opens the file, updates ONE band and exits - but I am finding that the file size almost doubles when I exit the file, despite the new band being the same data type etc. Code is as follows:

I am creating the GeoTiff file using the following creation options using many singular GeoTiff files:

gdal_merge.py -separate -co BIGTIFF=YES -co COMPRESS=DEFLATE -co PREDICTOR=1 -co TILED=YES -co BLOCKXSIZE=64 -co BLOCKYSIZE=64 -o block64.tif *.tif

The file size is 947MB.

I am then updating the file using the following code:

ds = gdal.Open("block64.tif", gdal.GA_Update) 

# Some simple operation to change band values
arr = ds.GetRasterBand(11).ReadAsArray() / 2
ds.GetRasterBand(11).WriteArray(arr)
ds.FlushCache()
ds = None

The file size is now 1.9GB.

My preliminary conclusion is that the compression/creation options are not being applied once I've updated and exited the file. Is there any way to re-compress/reapply the options once I close the file?

gdal geotiff-tiff compression bigtiff

share|improve this question

edited yesterday

PolyGeo♦

53.8k1781245

asked yesterday

tdatda

221214

• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  Compressed tiff is not optimal for updating but doubled size feels too much. Perhaps you could try something similar to the create vrt route in this wiki document trac.osgeo.org/gdal/wiki/UserDocs/…. If you do not get help from gis.stackexchange you should write and ask from the gdal-dev mailing list.
  
  – user30184
  yesterday
  

  
  
  
  


• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  More of a workaround than a real answer, but you could read all of the bands, remove the file, and recreate it with your updates.
  
  – mikewatt
  21 hours ago
  
  

  
  
  
  


• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  I could... and that's the answer I've come up with so far, but I'm trying to make the process as quick as possible and rewriting large files takes time (I'm updating files server-side and need to be quick to not impact client-side I/O requests).
  
  – tda
  11 hours ago
  

  
  
  
  

add a comment | 

I have a GeoTiff file with dimensions 300 x 300 and 8760 bands (hourly for one full year). I am testing some code that opens the file, updates ONE band and exits - but I am finding that the file size almost doubles when I exit the file, despite the new band being the same data type etc. Code is as follows:

I am creating the GeoTiff file using the following creation options using many singular GeoTiff files:

gdal_merge.py -separate -co BIGTIFF=YES -co COMPRESS=DEFLATE -co PREDICTOR=1 -co TILED=YES -co BLOCKXSIZE=64 -co BLOCKYSIZE=64 -o block64.tif *.tif

The file size is 947MB.

I am then updating the file using the following code:

ds = gdal.Open("block64.tif", gdal.GA_Update) 

# Some simple operation to change band values
arr = ds.GetRasterBand(11).ReadAsArray() / 2
ds.GetRasterBand(11).WriteArray(arr)
ds.FlushCache()
ds = None

The file size is now 1.9GB.

My preliminary conclusion is that the compression/creation options are not being applied once I've updated and exited the file. Is there any way to re-compress/reapply the options once I close the file?

gdal geotiff-tiff compression bigtiff

share|improve this question

edited yesterday

PolyGeo♦

53.8k1781245

asked yesterday

tdatda

221214

gdal_merge.py -separate -co BIGTIFF=YES -co COMPRESS=DEFLATE -co PREDICTOR=1 -co TILED=YES -co BLOCKXSIZE=64 -co BLOCKYSIZE=64 -o block64.tif *.tif

ds = gdal.Open("block64.tif", gdal.GA_Update) 

# Some simple operation to change band values
arr = ds.GetRasterBand(11).ReadAsArray() / 2
ds.GetRasterBand(11).WriteArray(arr)
ds.FlushCache()
ds = None

share|improve this question

edited yesterday

PolyGeo♦

53.8k1781245

asked yesterday

tdatda

221214

share|improve this question

edited yesterday

PolyGeo♦

53.8k1781245

asked yesterday

tdatda

221214

edited yesterday

PolyGeo♦

53.8k1781245

edited yesterday

PolyGeo♦

53.8k1781245

asked yesterday

tdatda

221214

asked yesterday

tdatda

221214