test_vectorize.py 文件源码

def test_simplify(self):
        """ Simplify GeoJSON geometries """
        geoimg = download_image(self.test_url)
        geoimg.set_nodata(0)
        lines = vectorize.potrace(geoimg[0] > 9500, close=0)
        fout = os.path.join(os.path.dirname(__file__), 'test.geojson')
        vectorize.save_geojson(lines, fout)

        # check file
        df = ogr.Open(fout)
        layer = df.GetLayer()
        self.assertEqual(layer.GetFeatureCount(), len(lines))
        geom = json.loads(layer.GetNextFeature().ExportToJson())
        self.assertEqual(len(geom['geometry']['coordinates']), len(lines[0]))
        df = None

        # simplify and check file
        vectorize.simplify(fout, tolerance=0.001)
        df = ogr.Open(fout)
        layer = df.GetLayer()
        geom = json.loads(layer.GetNextFeature().ExportToJson())
        self.assertEqual(len(geom['geometry']['coordinates']), 22)