Fixed #26417 -- Allowed setting GDALBand data with partial values.

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

@@ -170,7 +170,7 @@ class GDALBand(GDALBase):
             dtype = GDAL_PIXEL_TYPES[dtype]
         return dtype
 
-    def data(self, data=None, offset=None, size=None, as_memoryview=False):
+    def data(self, data=None, offset=None, size=None, shape=None, as_memoryview=False):
         """
         Reads or writes pixel values for this band. Blocks of data can
         be accessed by specifying the width, height and offset of the
@@ -185,6 +185,9 @@ class GDALBand(GDALBase):
         if not size:
             size = (self.width - offset[0], self.height - offset[1])
 
+        if not shape:
+            shape = size
+
         if any(x <= 0 for x in size):
             raise ValueError('Offset too big for this raster.')
 
@@ -192,7 +195,7 @@ class GDALBand(GDALBase):
             raise ValueError('Size is larger than raster.')
 
         # Create ctypes type array generator
-        ctypes_array = GDAL_TO_CTYPES[self.datatype()] * (size[0] * size[1])
+        ctypes_array = GDAL_TO_CTYPES[self.datatype()] * (shape[0] * shape[1])
 
         if data is None:
             # Set read mode
@@ -211,8 +214,8 @@ class GDALBand(GDALBase):
 
         # Access band
         capi.band_io(self._ptr, access_flag, offset[0], offset[1],
-                     size[0], size[1], byref(data_array), size[0],
+                     size[0], size[1], byref(data_array), shape[0],
-                     size[1], self.datatype(), 0, 0)
+                     shape[1], self.datatype(), 0, 0)
 
         # Return data as numpy array if possible, otherwise as list
         if data is None:

docs/ref/contrib/gis/gdal.txt

@@ -1477,7 +1477,7 @@ blue.
         ``GDT_UInt32``, ``GDT_Int32``, ``GDT_Float32``, ``GDT_Float64``,
         ``GDT_CInt16``, ``GDT_CInt32``, ``GDT_CFloat32``, and ``GDT_CFloat64``.
 
-    .. method:: data(data=None, offset=None, size=None)
+    .. method:: data(data=None, offset=None, size=None, shape=None)
 
         .. versionadded:: 1.9
 
@@ -1490,9 +1490,17 @@ blue.
 
         Data is written to the ``GDALBand`` if the ``data`` parameter is provided.
         The input can be of one of the following types - packed string, buffer, list,
-        array, and NumPy array. The number of items in the input must correspond to the
+        array, and NumPy array. The number of items in the input should normally
-        total number of pixels in the band, or to the number of pixels for a specific
+        correspond to the total number of pixels in the band, or to the number
-        block of pixel values if the ``offset`` and ``size`` parameters are provided.
+        of pixels for a specific block of pixel values if the ``offset`` and
+        ``size`` parameters are provided.
+
+        If the number of items in the input is different from the target pixel
+        block, the ``shape`` parameter must be specified. The shape is a tuple
+        that specifies the width and height of the input data in pixels. The
+        data is then replicated to update the pixel values of the selected
+        block. This is useful to fill an entire band with a single value, for
+        instance.
 
         For example:
 
@@ -1519,6 +1527,22 @@ blue.
                    [  4, -99, -88,   7],
                    [  8, -77, -66,  11],
                    [ 12,  13,  14,  15]], dtype=int8)
+            >>> bnd.data([1], shape=(1, 1))
+            >>> bnd.data()
+            array([[1, 1, 1, 1],
+                   [1, 1, 1, 1],
+                   [1, 1, 1, 1],
+                   [1, 1, 1, 1]], dtype=uint8)
+            >>> bnd.data(range(4), shape=(1, 4))
+            array([[0, 0, 0, 0],
+                   [1, 1, 1, 1],
+                   [2, 2, 2, 2],
+                   [3, 3, 3, 3]], dtype=uint8)
+
+    .. versionchanged:: 1.10
+
+        The ``shape`` parameter and the ability to replicate data input when
+        setting ``GDALBand`` data was added.
 
 Settings
 ========

docs/releases/1.10.txt

@@ -143,6 +143,10 @@ Minor features
   primary key of objects in the ``properties`` dictionary if specific fields
   aren't specified.
 
+* The ability to replicate input data on the :meth:`GDALBand.data()
+  <django.contrib.gis.gdal.GDALBand.data>` method was added. Band data can
+  now be updated with repeated values efficiently.
+
 :mod:`django.contrib.messages`
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 

tests/gis_tests/gdal_tests/test_raster.py

@@ -483,3 +483,24 @@ class GDALBandTests(SimpleTestCase):
         else:
             rsmem.bands[0].nodata_value = None
             self.assertIsNone(rsmem.bands[0].nodata_value)
+
+    def test_band_data_replication(self):
+        band = GDALRaster({
+            'srid': 4326,
+            'width': 3,
+            'height': 3,
+            'bands': [{'data': range(10, 19), 'nodata_value': 0}],
+        }).bands[0]
+
+        # Variations for input (data, shape, expected result).
+        combos = (
+            ([1], (1, 1), [1] * 9),
+            (range(3), (1, 3), [0, 0, 0, 1, 1, 1, 2, 2, 2]),
+            (range(3), (3, 1), [0, 1, 2, 0, 1, 2, 0, 1, 2]),
+        )
+        for combo in combos:
+            band.data(combo[0], shape=combo[1])
+            if numpy:
+                numpy.testing.assert_equal(band.data(), numpy.array(combo[2]).reshape(3, 3))
+            else:
+                self.assertEqual(band.data(), list(combo[2]))