Fixed #31713 -- Added SpatialReference support to GDALRaster.transform().

django/contrib/gis/gdal/raster/source.py

@@ -425,17 +425,24 @@ class GDALRaster(GDALRasterBase):
 
         return target
 
-    def transform(self, srid, driver=None, name=None, resampling='NearestNeighbour',
+    def transform(self, srs, driver=None, name=None, resampling='NearestNeighbour',
                   max_error=0.0):
         """
-        Return a copy of this raster reprojected into the given SRID.
+        Return a copy of this raster reprojected into the given spatial
+        reference system.
         """
         # Convert the resampling algorithm name into an algorithm id
         algorithm = GDAL_RESAMPLE_ALGORITHMS[resampling]
 
-        # Instantiate target spatial reference system
+        if isinstance(srs, SpatialReference):
-        target_srs = SpatialReference(srid)
+            target_srs = srs
-
+        elif isinstance(srs, (int, str)):
+            target_srs = SpatialReference(srs)
+        else:
+            raise TypeError(
+                'Transform only accepts SpatialReference, string, and integer '
+                'objects.'
+            )
         # Create warped virtual dataset in the target reference system
         target = capi.auto_create_warped_vrt(
             self._ptr, self.srs.wkt.encode(), target_srs.wkt.encode(),
@@ -445,7 +452,7 @@ class GDALRaster(GDALRasterBase):
 
         # Construct the target warp dictionary from the virtual raster
         data = {
-            'srid': srid,
+            'srid': target_srs.srid,
             'width': target.width,
             'height': target.height,
             'origin': [target.origin.x, target.origin.y],

docs/ref/contrib/gis/gdal.txt

@@ -1368,14 +1368,16 @@ blue.
                    [ 19.,  21.,  23.],
                    [ 31.,  33.,  35.]], dtype=float32)
 
-    .. method:: transform(srid, driver=None, name=None, resampling='NearestNeighbour', max_error=0.0)
+    .. method:: transform(srs, driver=None, name=None, resampling='NearestNeighbour', max_error=0.0)
 
-        Returns a transformed version of this raster with the specified SRID.
+        Transforms this raster to a different spatial reference system
+        (``srs``), which may be a :class:`SpatialReference` object, or any
+        other input accepted by :class:`SpatialReference` (including spatial
+        reference WKT and PROJ strings, or an integer SRID).
 
-        This function transforms the current raster into a new spatial reference
+        It calculates the bounds and scale of the current raster in the new
-        system that can be specified with an ``srid``. It calculates the bounds
+        spatial reference system and warps the raster using the
-        and scale of the current raster in the new spatial reference system and
+        :attr:`~GDALRaster.warp` function.
-        warps the raster using the :attr:`~GDALRaster.warp` function.
 
         By default, the driver of the source raster is used and the name of the
         raster is the original name appended with
@@ -1394,10 +1396,15 @@ blue.
             ...     "scale": [100, -100],
             ...     "bands": [{"data": range(36), "nodata_value": 99}]
             ... })
-            >>> target = rst.transform(4326)
+            >>> target_srs = SpatialReference(4326)
+            >>> target = rst.transform(target_srs)
             >>> target.origin
             [-82.98492744885776, 27.601924753080144]
 
+        .. versionchanged:: 3.2
+
+            Support for :class:`SpatialReference` ``srs`` was added
+
     .. attribute:: info
 
         Returns a string with a summary of the raster. This is equivalent to

docs/releases/3.2.txt

@@ -68,7 +68,8 @@ Minor features
 :mod:`django.contrib.gis`
 ~~~~~~~~~~~~~~~~~~~~~~~~~
 
-* ...
+* The :meth:`.GDALRaster.transform` method now supports
+  :class:`~django.contrib.gis.gdal.SpatialReference`.
 
 :mod:`django.contrib.messages`
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

tests/gis_tests/gdal_tests/test_raster.py

@@ -3,7 +3,7 @@ import shutil
 import struct
 import tempfile
 
-from django.contrib.gis.gdal import GDAL_VERSION, GDALRaster
+from django.contrib.gis.gdal import GDAL_VERSION, GDALRaster, SpatialReference
 from django.contrib.gis.gdal.error import GDALException
 from django.contrib.gis.gdal.raster.band import GDALBand
 from django.contrib.gis.shortcuts import numpy
@@ -471,62 +471,65 @@ class GDALRasterTests(SimpleTestCase):
         self.assertEqual(result, [23] * 16)
 
     def test_raster_transform(self):
-        # Prepare tempfile and nodata value
+        tests = [
-        rstfile = tempfile.NamedTemporaryFile(suffix='.tif')
+            3086,
-        ndv = 99
+            '3086',
+            SpatialReference(3086),
+        ]
+        for srs in tests:
+            with self.subTest(srs=srs):
+                # Prepare tempfile and nodata value.
+                rstfile = tempfile.NamedTemporaryFile(suffix='.tif')
+                ndv = 99
+                # Create in file based raster.
+                source = GDALRaster({
+                    'datatype': 1,
+                    'driver': 'tif',
+                    'name': rstfile.name,
+                    'width': 5,
+                    'height': 5,
+                    'nr_of_bands': 1,
+                    'srid': 4326,
+                    'origin': (-5, 5),
+                    'scale': (2, -2),
+                    'skew': (0, 0),
+                    'bands': [{
+                        'data': range(25),
+                        'nodata_value': ndv,
+                    }],
+                })
 
-        # Create in file based raster
+                target = source.transform(srs)
-        source = GDALRaster({
-            'datatype': 1,
-            'driver': 'tif',
-            'name': rstfile.name,
-            'width': 5,
-            'height': 5,
-            'nr_of_bands': 1,
-            'srid': 4326,
-            'origin': (-5, 5),
-            'scale': (2, -2),
-            'skew': (0, 0),
-            'bands': [{
-                'data': range(25),
-                'nodata_value': ndv,
-            }],
-        })
 
-        # Transform raster into srid 4326.
+                # Reload data from disk.
-        target = source.transform(3086)
+                target = GDALRaster(target.name)
+                self.assertEqual(target.srs.srid, 3086)
+                self.assertEqual(target.width, 7)
+                self.assertEqual(target.height, 7)
+                self.assertEqual(target.bands[0].datatype(), source.bands[0].datatype())
+                self.assertAlmostEqual(target.origin[0], 9124842.791079799, 3)
+                self.assertAlmostEqual(target.origin[1], 1589911.6476407414, 3)
+                self.assertAlmostEqual(target.scale[0], 223824.82664250192, 3)
+                self.assertAlmostEqual(target.scale[1], -223824.82664250192, 3)
+                self.assertEqual(target.skew, [0, 0])
 
-        # Reload data from disk
+                result = target.bands[0].data()
-        target = GDALRaster(target.name)
+                if numpy:
-
+                    result = result.flatten().tolist()
-        self.assertEqual(target.srs.srid, 3086)
+                # The reprojection of a raster that spans over a large area
-        self.assertEqual(target.width, 7)
+                # skews the data matrix and might introduce nodata values.
-        self.assertEqual(target.height, 7)
+                self.assertEqual(
-        self.assertEqual(target.bands[0].datatype(), source.bands[0].datatype())
+                    result,
-        self.assertAlmostEqual(target.origin[0], 9124842.791079799, 3)
+                    [
-        self.assertAlmostEqual(target.origin[1], 1589911.6476407414, 3)
+                        ndv, ndv, ndv, ndv, 4, ndv, ndv,
-        self.assertAlmostEqual(target.scale[0], 223824.82664250192, 3)
+                        ndv, ndv, 2, 3, 9, ndv, ndv,
-        self.assertAlmostEqual(target.scale[1], -223824.82664250192, 3)
+                        ndv, 1, 2, 8, 13, 19, ndv,
-        self.assertEqual(target.skew, [0, 0])
+                        0, 6, 6, 12, 18, 18, 24,
-
+                        ndv, 10, 11, 16, 22, 23, ndv,
-        result = target.bands[0].data()
+                        ndv, ndv, 15, 21, 22, ndv, ndv,
-        if numpy:
+                        ndv, ndv, 20, ndv, ndv, ndv, ndv,
-            result = result.flatten().tolist()
+                    ],
-
+                )
-        # The reprojection of a raster that spans over a large area
-        # skews the data matrix and might introduce nodata values.
-        self.assertEqual(
-            result,
-            [
-                ndv, ndv, ndv, ndv, 4, ndv, ndv,
-                ndv, ndv, 2, 3, 9, ndv, ndv,
-                ndv, 1, 2, 8, 13, 19, ndv,
-                0, 6, 6, 12, 18, 18, 24,
-                ndv, 10, 11, 16, 22, 23, ndv,
-                ndv, ndv, 15, 21, 22, ndv, ndv,
-                ndv, ndv, 20, ndv, ndv, ndv, ndv,
-            ]
-        )
 
 
 class GDALBandTests(SimpleTestCase):