Added output verification for get_overlap_polygon()

geo.vector.topology:
- get_overlap_polygon(): added output verification (automatic hole filling in case of MultiPolygon)

- updated __version__

ptds/__init__.py

@@ -15,7 +15,7 @@ __all__=[#'compatibility',
          'similarity',
          'GeoArray']
 
-__version__ = '20170221_01'
+__version__ = '20170221_02'
 __author__='Daniel Scheffler'
 
 # Validate GDAL version

ptds/geo/vector/topology.py

@@ -24,6 +24,12 @@ def get_overlap_polygon(poly1, poly2, v=False):
     """
     overlap_poly = poly1.intersection(poly2)
     if not overlap_poly.is_empty:
+        # check if output is MULTIPOLYGON -> if yes, convert to POLYGON
+        if overlap_poly.geom_type == 'MultiPolygon':
+            overlap_poly = fill_holes_within_poly(overlap_poly)
+        assert overlap_poly.geom_type=='Polygon', \
+            "get_overlap_polygon() did not return geometry type 'Polygon' but %s." %overlap_poly.geom_type
+
         overlap_percentage = 100 * shape(overlap_poly).area / shape(poly2).area
         if v: print('%.2f percent of the image to be shifted is covered by the reference image.' % overlap_percentage)
         return {'overlap poly':overlap_poly, 'overlap percentage':overlap_percentage, 'overlap area':overlap_poly.area}

ptds/io/raster/GeoArray.py

@@ -420,10 +420,9 @@ class GeoArray(object):
     def footprint_poly(self):
         # FIXME should return polygon in image coordinates if no projection is available
 
-        """Get the footprint polygon of the associated image array (returns an instance of shapely.geometry.Polygon."""
-        if self._footprint_poly is not None:
-            return self._footprint_poly
-        else:
+        """Get the footprint polygon of the associated image array (returns an instance of shapely.geometry.Polygon.
+        """
+        if self._footprint_poly is None:
             assert self.mask_nodata is not None, 'A nodata mask is needed for calculating the footprint polygon. '
             if np.std(self.mask_nodata[:])==0:
                 # do not run raster2polygon if whole image is filled with data
@@ -450,8 +449,7 @@ class GeoArray(object):
             #    assert self.GeoArray.box.mapPoly.contains(Point(XY)) or self.GeoArray.box.mapPoly.touches(Point(XY)), \
             #        "The corner position '%s' is outside of the %s." % (XY, self.imName)
 
-
-            return self._footprint_poly
+        return self._footprint_poly
 
 
     @footprint_poly.setter
@@ -797,7 +795,8 @@ class GeoArray(object):
 
         driver = gdal.GetDriverByName(fmt)
         if driver is None:
-            raise Exception("'%s' is not a supported GDAL driver." % fmt)
+            raise Exception("'%s' is not a supported GDAL driver. Refer to www.gdal.org/formats_list.html for full "
+                            "list of GDAL driver codes." % fmt)
 
         if not os.path.isdir(os.path.dirname(out_path)):
             os.makedirs(os.path.dirname(out_path))