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pythongdalrasterio

Chaining virtual file system drivers in rasterio

In plain gdal it's quite straightforward to chain multiple vsi drivers to e.g. directly access a .tif.gz file:

import gdal
import rasterio as rio

## just an example, no real URL

# will work
ds = gdal.Open('/vsigzip//vsicurl/https://testdata.com/testimage.tif.gz')

# won't work
ds = rio.open('/vsigzip/https://testdata.com/testimage.tif.gz')

Is it an issue with chaining or can rasterio just not handle .gz files?

Solution

  • I just ran through this and gzip support within RasterIO (v1.0.21) checks out ok. Seems you've just missed the //vsicurl.

    import rasterio as rio

ds = rio.open('/vsigzip//vsicurl/http://localhost:8000/example.tif.gz')

    The http server needs to support range requests, but if it doesn't RasterIO will produce a specific error message.

    Interestingly the Apache Commons VFS scheme doesn't seem to work here;

    ds = rio.open('gzip+http://localhost:8000/example.tif.gz')

    Produces the following. Note missing / before vsicurl

    Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/home/ubuntu/anaconda3/envs/rasterio-env/lib/python3.7/site-packages/rasterio/env.py", line 423, in wrapper
    return f(*args, **kwds)
  File "/home/ubuntu/anaconda3/envs/rasterio-env/lib/python3.7/site-packages/rasterio/__init__.py", line 216, in open
    s = DatasetReader(path, driver=driver, **kwargs)
  File "rasterio/_base.pyx", line 215, in rasterio._base.DatasetBase.__init__
rasterio.errors.RasterioIOError: '/vsizip/vsicurl/http://localhost:8000/example.tif.gz' does not exist in the file system, and is not recognized as a supported dataset name.