fix inverted hillshade & misleading tile reference (#229) (#232)

* fix inverted hillshade & misleading tile reference (#229)

CHANGELOG.rst

@@ -7,7 +7,8 @@ Changelog
 ----
 * don't raise exception when one of the registered processes cannot be imported (#225)
 * don't close pool between zoom levels (#227)
-* ``_validate`` module renamed to ``validate``
+* ``_validate`` module renamed to ``validate`` (#230)
+* fix inverted hillshade & misleading tile reference (#229)
 
 ----
 0.30

mapchete/_processing.py

@@ -286,7 +286,9 @@ def hillshade(
         -------
         hillshade : array
         """
-        return commons_hillshade.hillshade(elevation, self, azimuth, altitude, z, scale)
+        return commons_hillshade.hillshade(
+            elevation, self.tile, azimuth, altitude, z, scale
+        )
 
     def contours(
         self, elevation, interval=100, field='elev', base=0

mapchete/commons/contours.py

@@ -11,8 +11,8 @@ def extract_contours(array, tile, interval=100, field='elev', base=0):
     ----------
     array : array
         input elevation data
-    tile : Tile
-        tile covering the array
+    mp : mapchete.MapcheteProcess
+        process object
     interval : integer
         elevation value interval when drawing contour lines
     field : string

mapchete/commons/hillshade.py

@@ -107,8 +107,8 @@ def hillshade(elevation, tile, azimuth=315.0, altitude=45.0, z=1.0, scale=1.0, )
     altitude = float(altitude)
     z = float(z)
     scale = float(scale)
-    xres = tile.tile.pixel_x_size
-    yres = -tile.tile.pixel_y_size
+    xres = tile.pixel_x_size
+    yres = -tile.pixel_y_size
     slope, aspect = calculate_slope_aspect(
         elevation,
         xres,
@@ -117,13 +117,16 @@ def hillshade(elevation, tile, azimuth=315.0, altitude=45.0, z=1.0, scale=1.0, )
         scale=scale
     )
     deg2rad = math.pi / 180.0
+    # shaded has values between -1.0 and +1.0
     shaded = np.sin(altitude * deg2rad) * np.sin(slope) \
         + np.cos(altitude * deg2rad) * np.cos(slope) \
         * np.cos((azimuth - 90.0) * deg2rad - aspect)
-    # shaded now has values between -1.0 and +1.0
-    # stretch to 0 - 255 and invert
-    shaded = (((shaded + 1.0) / 2) * -255.0).astype("uint8")
-    # add one pixel padding using the edge values
+    # stretch to 0 - 255 and add one pixel padding using the edge values
     return ma.masked_array(
-        data=np.pad(shaded, 1, mode='edge'), mask=elevation.mask
+        data=np.pad(
+            np.clip(shaded * 255.0, 1, 255).astype("uint8"),
+            1,
+            mode='edge'
+        ),
+        mask=elevation.mask
     )

mapchete/formats/default/png_hillshade.py

@@ -193,14 +193,12 @@ def empty(self, process_tile):
         return ma.masked_values(np.zeros(process_tile.shape), 0)
 
     def _prepare_array(self, data):
-        data = prepare_array(
-            -(data - 255), dtype="uint8", masked=False, nodata=0)
+        data = prepare_array(-(data - 255), dtype="uint8", masked=False, nodata=0)[0]
+        zeros = np.zeros(data.shape)
         if self.old_band_num:
-            data = np.stack((
-                np.zeros(data[0].shape), np.zeros(data[0].shape),
-                np.zeros(data[0].shape), data[0]))
+            data = np.stack([zeros, zeros, zeros, data])
         else:
-            data = np.stack((np.zeros(data[0].shape), data[0]))
+            data = np.stack([zeros, data])
         return prepare_array(data, dtype="uint8", masked=True, nodata=255)
 
 

test/test_cli.py

@@ -593,27 +593,27 @@ def test_serve(client, mp_tmpdir):
         response = client.get(url)
         assert response.status_code == 200
     for url in [
-        tile_base_url+"5/30/62.png",
-        tile_base_url+"5/30/63.png",
-        tile_base_url+"5/31/62.png",
-        tile_base_url+"5/31/63.png",
+        tile_base_url + "5/30/62.png",
+        tile_base_url + "5/30/63.png",
+        tile_base_url + "5/31/62.png",
+        tile_base_url + "5/31/63.png",
     ]:
         response = client.get(url)
         assert response.status_code == 200
         img = response.data
         with MemoryFile(img) as memfile:
             with memfile.open() as dataset:
                 data = dataset.read()
-                # get alpha band and assert not all are masked
-                assert not data[3].all()
+                # get alpha band and assert some pixels are masked
+                assert data[3].any()
     # test outside zoom range
     response = client.get(tile_base_url + "6/31/63.png")
     assert response.status_code == 200
     img = response.data
     with MemoryFile(img) as memfile:
         with memfile.open() as dataset:
             data = dataset.read()
-            assert not data.any()
+            assert not data.all()
     # test invalid url
     response = client.get(tile_base_url + "invalid_url")
     assert response.status_code == 404