Fixed issue #5 (Classification map does not label nodata pixels when calling...

Fixed issue #5

 (Classification map does not label nodata pixels when calling classify_image() with unclassified_threshold=None). Added default CMAP nodata value.
Signed-off-by: Daniel Scheffler <danschef@gfz-potsdam.de>

specclassify/_baseclasses.py

@@ -24,7 +24,7 @@
 """Base classes for specclassify."""
 
 import numpy as np
-from typing import Union, List  # noqa F401  # flake8 issue
+from typing import Union, List, Tuple  # noqa F401  # flake8 issue
 from multiprocessing import Pool
 from tqdm import tqdm
 from matplotlib import pyplot as plt
@@ -76,7 +76,8 @@ class _ImageClassifier(object):
 
         return tilepos, cmap, dists
 
-    def classify(self, image_cube, in_nodataVal=None, cmap_nodataVal=None, tiledims=(100, 100)):
+    def classify(self, image_cube, in_nodataVal=None, cmap_nodataVal=-9999, tiledims=(100, 100)):
+        # type: (Union[GeoArray, np.ndarray], int, int, Tuple[int, int]) -> GeoArray
         """Classify the image.
 
         :param image_cube:
@@ -85,16 +86,23 @@ class _ImageClassifier(object):
         :param tiledims:
         :return:
         """
+        if not isinstance(cmap_nodataVal, int):
+            raise TypeError(cmap_nodataVal, "Expected an integer.")
+
         self._cmap_nodataVal = cmap_nodataVal
 
         dtype_cmap = np.int16
         if cmap_nodataVal is not None and not np.can_cast(cmap_nodataVal, dtype_cmap):
             dtype_cmap = np.find_common_type(np.array(self.train_labels), np.array([cmap_nodataVal]))
 
-        image_cube_gA = GeoArray(image_cube, nodata=in_nodataVal)  # lazily read in tiles to save memory
+        # lazily read in tiles to save memory
+        image_cube_gA = GeoArray(image_cube, nodata=in_nodataVal)
 
         bounds_alltiles = get_array_tilebounds(image_cube_gA.shape, tiledims)
 
+        # run classification #
+        ######################
+
         print('Performing %s image classification...' % self.clf_name)
         if self.CPUs is None or self.CPUs > 1:
             with Pool(self.CPUs, initializer=_mp_initializer, initargs=(self.train_spectra, image_cube_gA)) as pool:
@@ -105,7 +113,8 @@ class _ImageClassifier(object):
             tiles_results = [self._predict_tilewise(bounds) for bounds in tqdm(bounds_alltiles)]
 
         # use a local variable to avoid pickling in multiprocessing
-        cmap_dist_shape = (image_cube_gA.rows, image_cube_gA.cols) if tiles_results[0][1].ndim == 2 else \
+        cmap_dist_shape = \
+            (image_cube_gA.rows, image_cube_gA.cols) if tiles_results[0][1].ndim == 2 else \
             (image_cube_gA.rows, image_cube_gA.cols, tiles_results[0][1].shape[2])
         cmap = GeoArray(np.empty(cmap_dist_shape, dtype=dtype_cmap), nodata=cmap_nodataVal)
         cmap.unclassified_val = None
@@ -114,9 +123,12 @@ class _ImageClassifier(object):
         for tile_res in tiles_results:
             ((rS, rE), (cS, cE)), tile_cm = tile_res[:2]
             cmap[rS: rE + 1, cS: cE + 1] = tile_cm
+
             if len(tile_res) == 3:
                 dist[rS: rE + 1, cS: cE + 1] = tile_res[2]
 
+        ######################
+
         self.cmap = cmap
         if len(tiles_results[0]) == 3:
             self._distance_metrics = dist
@@ -133,8 +145,9 @@ class _ImageClassifier(object):
         :param imdata:
         :return:
         """
-        if imdata.nodata is not None and self._cmap_nodataVal is not None:
+        if imdata.nodata is not None:
             mask_anynodata = np.any(imdata[:] == imdata.nodata, axis=2)
+
             cmap[mask_anynodata] = self._cmap_nodataVal
 
         return cmap

specclassify/classify.py

@@ -35,7 +35,7 @@ global_shared_endmembers = None  # type: Union[None, np.ndarray]
 global_shared_im2classify = None  # type: Union[None, GeoArray]
 
 
-def classify_image(image, train_spectra, train_labels, classif_alg, in_nodataVal=None, cmap_nodataVal=None,
+def classify_image(image, train_spectra, train_labels, classif_alg, in_nodataVal=None, cmap_nodataVal=-9999,
                    tiledims=(1000, 1000), CPUs=None, return_distance=False, unclassified_threshold=None,
                    unclassified_pixVal=-1, **kwargs):
     # type: (Union[np.ndarray, GeoArray], np.ndarray, Union[np.ndarray, List[int]], str, int, int, tuple, int, bool, Union[int, float, str], int, dict) -> Union[GeoArray, Tuple[GeoArray, np.ndarray]]  # noqa E501

tests/test_image_classifier.py

@@ -73,11 +73,15 @@ def _get_testIm(shape, nodataVal):
                                size=spec.shape[0]//10), :] = \
             cluster_centers[i, :]
 
+    # fill remaining nodata positions with first spectrum
+    spec[spec[:, 0] == nodataVal, :] = cluster_centers[0, :]
+
     # add 10% noise to each spectrum
-    spec = spec * np.random.normal(1, .1, spec.size).reshape(spec.shape)
+    noise_factor = np.random.normal(1, .1, spec.size).reshape(spec.shape)
+    spec_out = spec * noise_factor
 
     # return in desired image dimensions
-    return spec.reshape(shape)
+    return spec_out.reshape(shape)
 
 
 test_gA = GeoArray(_get_testIm(shape=(1010, 1010, 6),
@@ -109,12 +113,12 @@ class Test_MinimumDistance_Classifier(unittest.TestCase):
 
     def test_label_unclassified_pixels_absolute_th(self):
         MDC = MinimumDistance_Classifier(cluster_centers, cluster_labels, CPUs=1)
-        MDC.classify(test_gA, in_nodataVal=-9999,  cmap_nodataVal=-9999, tiledims=(400, 200))
+        MDC.classify(test_gA, in_nodataVal=-9999, cmap_nodataVal=-9999, tiledims=(400, 200))
         MDC.label_unclassified_pixels(label_unclassified=-1, threshold=6000)
 
     def test_label_unclassified_pixels_relative_th(self):
         MDC = MinimumDistance_Classifier(cluster_centers, cluster_labels, CPUs=1)
-        MDC.classify(test_gA, in_nodataVal=-9999,  cmap_nodataVal=-9999, tiledims=(400, 200))
+        MDC.classify(test_gA, in_nodataVal=-9999, cmap_nodataVal=-9999, tiledims=(400, 200))
         MDC.label_unclassified_pixels(label_unclassified=-1, threshold='10%')
 
 
@@ -226,22 +230,40 @@ class Test_kNN_SAM_Classifier(unittest.TestCase):
 
     def test_classification_outputs(self):
         SC = kNN_SAM_Classifier(cluster_centers, n_neighbors=self.n_neighbors, CPUs=1)
-        cmap = SC.classify(test_gA, in_nodataVal=None, cmap_nodataVal=None, tiledims=(400, 200))
+        cmap = SC.classify(test_gA, in_nodataVal=-9999, tiledims=(400, 200))
 
-        # check if first 20 pixels in col 0 contain the same cmap value (input image is nodata in all bands there)
+        # check if first 20 pixels in col 0 contain the nodata value (input image is nodata in all bands there)
         vals = np.unique(cmap[:20, 0, :])
-        self.assertEqual(len(vals), self.n_neighbors)  # n differnt neighbors
+        self.assertEqual(len(vals), 1)  # only the unclassified value
+        self.assertEqual(vals[0], -9999)  # default nodata value
+
+        # check if first 20 pixels in col 1 contain the nodata value (input image is nodata in one band there)
+        # (nodata in one band would cause faulty results due to wrong spectral distance measures)
+        vals = np.unique(cmap[:20, 1, :])
+        self.assertEqual(len(vals), 1)  # only the unclassified value
+        self.assertEqual(vals[0], -9999)  # default nodata value
+
+        # check if the cmap contains only values between 0 and 49 in the rest of the image
+        vals = np.unique(cmap[:, 2:, :])
         self.assertTrue(0 <= min(vals) < cluster_centers.shape[0])  # cmap values min between 0 and 49
         self.assertTrue(0 <= max(vals) < cluster_centers.shape[0])  # cmap values max between 0 and 49
 
-        # check if first 20 pixels in col 1 contain the different cmap value (input image has values in some bands)
-        vals = np.unique(cmap[:20, 1, :])
-        self.assertGreater(len(vals), self.n_neighbors)  # n different neighbors
+    def test_classification_outputs_inNodataVal_not_given(self):
+        gA = GeoArray(test_gA[:], nodata=None)
+
+        SC = kNN_SAM_Classifier(cluster_centers, n_neighbors=self.n_neighbors, CPUs=1)
+        cmap = SC.classify(gA, tiledims=(400, 200))
+
+        # check if first 20 pixels in col 0 contain the unclassified value (input image is nodata in all bands there)
+        # (if no nodata values are given, the nodata positions must at least be labelled as unclassified via the dists)
+        vals = np.unique(cmap[:20, 0, :])
+        self.assertEqual(len(vals), self.n_neighbors)  # n different neighbors
         self.assertTrue(0 <= min(vals) < cluster_centers.shape[0])  # cmap values min between 0 and 49
         self.assertTrue(0 <= max(vals) < cluster_centers.shape[0])  # cmap values max between 0 and 49
 
-        # check if the cmap contains only values between 0 and 49 in the rest of the image
-        vals = np.unique(cmap[:, 2:, :])
+        # check if first 20 pixels in col 1 contain varying cmap values (input image has values in some bands)
+        vals = np.unique(cmap[:20, 1, :])
+        self.assertGreater(len(vals), self.n_neighbors)  # n different neighbors
         self.assertTrue(0 <= min(vals) < cluster_centers.shape[0])  # cmap values min between 0 and 49
         self.assertTrue(0 <= max(vals) < cluster_centers.shape[0])  # cmap values max between 0 and 49
 
@@ -277,16 +299,20 @@ class Test_kNN_SAM_Classifier(unittest.TestCase):
 
     def test_label_unclassified_pixels_cmapNodataVal_not_given(self):
         SC = kNN_SAM_Classifier(cluster_centers, n_neighbors=self.n_neighbors, CPUs=None)
-        SC.classify(test_gA, in_nodataVal=-9999, cmap_nodataVal=None, tiledims=(400, 200))
+        SC.classify(test_gA, in_nodataVal=-9999, tiledims=(400, 200))
 
         # now label all pixels with SAM above 10 degrees with -1
         cmap = SC.label_unclassified_pixels(label_unclassified=-1, threshold=10)
 
-        # check if first 20 pixels in cols 0 and 1 contain only -1
-        # (nodata pixels in the input image should appear as unclassified in the cmap (-1) if cmap_nodataVal=None)
+        # check if first 20 pixels in cols 0 and 1 keep untouched (must contain -9999 due to nodata in the input image)
+        # (nodata pixels in the input image should appear as nodata in the cmap (-9999)
         vals = np.unique(cmap[:20, :2, :])
         self.assertEqual(len(vals), 1)
-        self.assertEqual(vals[0], -1)
+        self.assertEqual(vals[0], -9999)
+
+        # check if there are pixels in the rest of the image that are labelled as unclassified
+        vals = np.unique(cmap[:, 2:, :])
+        self.assertTrue(-1 in vals)
 
 
 class Test_FEDSA_Classifier(unittest.TestCase):