Make shape, rows and columns properties of GridObject (TopoToolbox#93)

See the discussion in TopoToolbox#90.

This ensures that these attributes remain synchronized with the
underlying Numpy array that stores the data, but should not change the
API of the object. It will break code that directly sets these
attributes. I believe I have found and corrected all of those in
the package.

src/topotoolbox/flow_object.py

@@ -146,7 +146,6 @@ def flow_accumulation(self, weights: np.ndarray | float = 1.0):
         result.name = self.name
 
         result.z = acc
-        result.shape = self.shape
         result.cellsize = self.cellsize
 
         result.bounds = self.bounds

src/topotoolbox/grid_object.py

@@ -30,9 +30,6 @@ def __init__(self) -> None:
 
         # raster metadata
         self.z = np.empty((), order='F', dtype=np.float32)
-        self.rows = 0
-        self.columns = 0
-        self.shape = self.z.shape
 
         self.cellsize = 0.0  # in meters if crs.is_projected == True
 
@@ -41,6 +38,24 @@ def __init__(self) -> None:
         self.transform = None
         self.crs = None
 
+    @property
+    def shape(self):
+        """Tuple of grid dimensions
+        """
+        return self.z.shape
+
+    @property
+    def rows(self):
+        """The size of the first dimension of the grid
+        """
+        return self.z.shape[0]
+
+    @property
+    def columns(self):
+        """The size of the second dimension of the grid
+        """
+        return self.z.shape[1]
+
     def reproject(self,
                   crs: 'CRS',
                   resolution: 'float | None' = None,
@@ -87,10 +102,6 @@ def reproject(self,
         if dst.transform is not None:
             dst.cellsize = abs(dst.transform[0])
 
-        dst.shape = dst.z.shape
-        dst.rows = dst.shape[0]
-        dst.columns = dst.shape[1]
-
         return dst
 
     def fillsinks(self,

src/topotoolbox/utils.py

@@ -130,9 +130,6 @@ def read_tif(path: str) -> GridObject:
         grid.name = os.path.splitext(os.path.basename(grid.path))[0]
 
         grid.z = dataset.read(1).astype(np.float32, order='F')
-        grid.rows = dataset.height
-        grid.columns = dataset.width
-        grid.shape = grid.z.shape
 
         grid.cellsize = dataset.res[0]
         grid.bounds = dataset.bounds
@@ -192,9 +189,6 @@ def gen_random(hillsize: int = 24, rows: int = 128, columns: int = 128,
     grid = GridObject()
 
     grid.z = noise_array
-    grid.rows = rows
-    grid.columns = columns
-    grid.shape = grid.z.shape
     grid.cellsize = cellsize
     grid.name = name
     return grid
@@ -230,9 +224,6 @@ def gen_random_bool(
 
     grid.path = ''
     grid.z = bool_array
-    grid.rows = rows
-    grid.columns = columns
-    grid.shape = grid.z.shape
     grid.cellsize = cellsize
     grid.name = name
 

tests/test_flow_object.py

@@ -12,6 +12,9 @@ def test_flowobject(wide_dem):
     original_dem = dem.z.copy()
     fd = topo.FlowObject(dem);
 
+    # Run flow_accumulation at least once during the tests
+    acc = fd.flow_accumulation();
+
     # Ensure that FlowObject does not modify the original DEM
     assert np.all(dem.z == original_dem)