Fixed #32670 -- Allowed GDALRasters to use any GDAL virtual filesystem.

This commit is contained in:
Jordi Castells 2021-04-14 16:07:36 +02:00 committed by Mariusz Felisiak
parent 028f10fac6
commit 205c36b58f
6 changed files with 91 additions and 11 deletions

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@ -1111,9 +1111,9 @@ blue.
raster should be opened in write mode. For newly-created rasters, the second
parameter is ignored and the new raster is always created in write mode.
The first parameter can take three forms: a string representing a file
path, a dictionary with values defining a new raster, or a bytes object
representing a raster file.
The first parameter can take three forms: a string representing a file path
(filesystem or GDAL virtual filesystem), a dictionary with values defining
a new raster, or a bytes object representing a raster file.
If the input is a file path, the raster is opened from there. If the input
is raw data in a dictionary, the parameters ``width``, ``height``, and
@ -1164,6 +1164,10 @@ blue.
>>> rst.name # Stored in a random path in the vsimem filesystem.
'/vsimem/da300bdb-129d-49a8-b336-e410a9428dad'
.. versionchanged:: 4.0
Creating rasters in any GDAL virtual filesystem was allowed.
.. attribute:: name
The name of the source which is equivalent to the input file path or the name
@ -1772,6 +1776,13 @@ Key Default Usage
Using GDAL's Virtual Filesystem
-------------------------------
GDAL can access files stored in the filesystem, but also supports virtual
filesystems to abstract accessing other kind of files, such as compressed,
encrypted, or remote files.
Using memory-based Virtual Filesystem
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
GDAL has an internal memory-based filesystem, which allows treating blocks of
memory as files. It can be used to read and write :class:`GDALRaster` objects
to and from binary file buffers.
@ -1817,6 +1828,53 @@ Here's how to create a raster and return it as a file in an
... })
>>> HttpResponse(rast.vsi_buffer, 'image/tiff')
Using other Virtual Filesystems
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
.. versionadded:: 4.0
Depending on the local build of GDAL other virtual filesystems may be
supported. You can use them by prepending the provided path with the
appropriate ``/vsi*/`` prefix. See the `GDAL Virtual Filesystems
documentation`_ for more details.
.. warning:
Rasters with names starting with `/vsi*/` will be treated as rasters from
the GDAL virtual filesystems. Django doesn't perform any extra validation.
Compressed rasters
^^^^^^^^^^^^^^^^^^
Instead decompressing the file and instantiating the resulting raster, GDAL can
directly access compressed files using the ``/vsizip/``, ``/vsigzip/``, or
``/vsitar/`` virtual filesystems::
>>> from django.contrib.gis.gdal import GDALRaster
>>> rst = GDALRaster('/vsizip/path/to/your/file.zip/path/to/raster.tif')
>>> rst = GDALRaster('/vsigzip/path/to/your/file.gz')
>>> rst = GDALRaster('/vsitar/path/to/your/file.tar/path/to/raster.tif')
Network rasters
^^^^^^^^^^^^^^^
GDAL can support online resources and storage providers transparently. As long
as it's built with such capabilities.
To access a public raster file with no authentication, you can use
``/vsicurl/``::
>>> from django.contrib.gis.gdal import GDALRaster
>>> rst = GDALRaster('/vsicurl/https://example.com/raster.tif')
>>> rst.name
'/vsicurl/https://example.com/raster.tif'
For commercial storage providers (e.g. ``/vsis3/``) the system should be
previously configured for authentication and possibly other settings (see the
`GDAL Virtual Filesystems documentation`_ for available options).
.. _`GDAL Virtual Filesystems documentation`: https://gdal.org/user/virtual_file_systems.html
Settings
========