def test_elevation(self): # Create a simple fake DEM conn = connections[DEFAULT_DB_ALIAS] cur = conn.cursor() cur.execute('CREATE TABLE mnt (rid serial primary key, rast raster)') cur.execute('INSERT INTO mnt (rast) VALUES (ST_MakeEmptyRaster(3, 3, 0, 3, 1, -1, 0, 0, %s))', [settings.SRID]) cur.execute('UPDATE mnt SET rast = ST_AddBand(rast, \'16BSI\')') for x in range(1, 4): for y in range(1, 4): cur.execute('UPDATE mnt SET rast = ST_SetValue(rast, %s, %s, %s::float)', [x, y, x+y]) conn.commit_unless_managed() # Create a geometry and check elevation-based indicators p = Path(geom=LineString((1.5,1.5,0), (2.5,1.5,0), (1.5,2.5,0))) self.assertEqual(p.ascent, 0) self.assertEqual(p.descent, 0) self.assertEqual(p.min_elevation, 0) self.assertEqual(p.max_elevation, 0) p.save() self.assertEqual(p.ascent, 1) self.assertEqual(p.descent, -2) self.assertEqual(p.min_elevation, 3) self.assertEqual(p.max_elevation, 5) # Check elevation profile profile = p.get_elevation_profile() self.assertEqual(len(profile), 3) self.assertEqual(profile[0][0], 0.0) self.assertEqual(profile[0][1], 4) self.assertTrue(1.4 < profile[1][0] < 1.5) self.assertEqual(profile[1][1], 5) self.assertTrue(3.8 < profile[2][0] < 3.9) self.assertEqual(profile[2][1], 3)
def test_elevation_path(self): # Create a geometry and check elevation-based indicators p = Path(geom=LineString((1.5,1.5,0), (2.5,1.5,0), (1.5,2.5,0))) self.assertEqual(p.ascent, 0) self.assertEqual(p.descent, 0) self.assertEqual(p.min_elevation, 0) self.assertEqual(p.max_elevation, 0) p.save() self.assertEqual(p.ascent, 1) self.assertEqual(p.descent, -2) self.assertEqual(p.min_elevation, 3) self.assertEqual(p.max_elevation, 5) # Check elevation profile profile = p.get_elevation_profile() self.assertEqual(len(profile), 4) # minimum possible (since p.length < sampling resolution) self.assertEqual(profile[0][0], 0.0) self.assertEqual(profile[0][3], 4) self.assertTrue(2.4 < profile[-1][0] < 2.5) # p.geom.length self.assertEqual(profile[-1][3], 3)