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I would like to know if the STATISTICS_VALID_PERCENT (percentage of valid (not nodata) pixels) information is accessible through the GDAL Python API?

It seems to be missing from the GetStatistics Function.

As a work around, I have been scraping this information from the PAMDataset (XML file) generated through the GetStatistics(False, True) call.

Is there a better way?

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"Better" is subjective, so I won't claim that this is. But I much prefer using rasterio to "raw" GDAL or its python bindings. So if I wanted to know the fraction of cells with valid values, I would do the following:

Rasterio Approach

import rasterio
with rasterio.open('path/to/my/image.tif', 'r') as src:
    meta = src.meta.copy()
    data = src.read(1)

pct_valid = 100 * (data != meta['nodata']).sum() / (meta['width'] * meta['height'])

"Raw" GDAL

Alternatively, here's how you'd do it with GDAL's python bindings directly:

import gdal
gtif = gdal.Open('path/to/my/image.tif')
data = gtif.GetRasterBand(1).ReadAsArray()
nd_val = band.GetNoDataValue()

pct_valid = 100 * (data != nd_val).sum() / (band.XSize * band.YSize)
gtif = None

Also consider

The raster_stats package may be even more concise, but I think it would required to you generate a vector layer encompassing the whole raster.

Links:

  1. rasterio: https://rasterio.readthedocs.io/en/stable/
  2. raster_stats: https://pythonhosted.org/rasterstats/index.html
  • Thanks for the response. I agree that rasterio is generally easier to use and provides several advantages over the straight GDAL API. I would however prefer to stay within the confines of GDAL for my particular use case. – Brent Edwards Mar 14 at 13:20
  • hey @BrentEdwards added a GDAL-based approach – Paul H Mar 14 at 16:13
  • Thanks Paul H! This should work in cases where the raster is small enough to be read directly into an array and thus avoiding the pain of windowing in GDAL. – Brent Edwards Mar 14 at 16:32

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