gis: geos: Added support for EWKT (SRID only), and a transform routine that uses the GDAL facilities to transform the GEOS geometry.

git-svn-id: http://code.djangoproject.com/svn/django/branches/gis@6884 bcc190cf-cafb-0310-a4f2-bffc1f526a37

django/contrib/gis/geos/base.py

@@ -29,7 +29,7 @@ except:
 # to prevent potentially malicious input from reaching the underlying C
 # library.  Not a substitute for good web security programming practices.
 hex_regex = re.compile(r'^[0-9A-F]+$', re.I)
-wkt_regex = re.compile(r'^(POINT|LINESTRING|LINEARRING|POLYGON|MULTIPOINT|MULTILINESTRING|MULTIPOLYGON|GEOMETRYCOLLECTION)[ACEGIMLONPSRUTY\d,\.\-\(\) ]+$', re.I)
+wkt_regex = re.compile(r'^(SRID=(?P<srid>\d+);)?(?P<wkt>(POINT|LINESTRING|LINEARRING|POLYGON|MULTIPOINT|MULTILINESTRING|MULTIPOLYGON|GEOMETRYCOLLECTION)[ACEGIMLONPSRUTY\d,\.\-\(\) ]+)$', re.I)
 
 class GEOSGeometry(object):
     "A class that, generally, encapsulates a GEOS geometry."
@@ -57,11 +57,13 @@ class GEOSGeometry(object):
             if hex_regex.match(geo_input):
                 # If the regex matches, the geometry is in HEX form.
                 g = from_hex(geo_input, len(geo_input))
-            elif wkt_regex.match(geo_input):
-                # Otherwise, the geometry is in WKT form.
-                g = from_wkt(geo_input)
             else:
-                raise ValueError('String or unicode input unrecognized as WKT or HEXEWKB.')
+                m = wkt_regex.match(geo_input)
+                if m:
+                    if m.group('srid'): srid = int(m.group('srid'))
+                    g = from_wkt(m.group('wkt'))
+                else:
+                    raise ValueError('String or unicode input unrecognized as WKT EWKT, and HEXEWKB.')
         elif isinstance(geo_input, GEOM_PTR):
             # When the input is a pointer to a geomtry (GEOM_PTR).
             g = geo_input
@@ -303,6 +305,12 @@ class GEOSGeometry(object):
     srid = property(get_srid, set_srid)
 
     #### Output Routines ####
+    @property
+    def ewkt(self):
+        "Returns the EWKT (WKT + SRID) of the Geometry."
+        if self.get_srid(): return 'SRID=%s;%s' % (self.srid, self.wkt)
+        else: return self.wkt
+
     @property
     def wkt(self):
         "Returns the WKT (Well-Known Text) of the Geometry."
@@ -356,6 +364,22 @@ class GEOSGeometry(object):
         "Alias for `srs` property."
         return self.srs
 
+    def transform(self, ct):
+        "Transforms this Geometry; only works with GDAL."
+        srid = self.srid
+        if HAS_GDAL and srid:
+            g = OGRGeometry(self.wkb, srid)
+            g.transform(ct)
+            wkb = str(g.wkb)
+            ptr = from_wkb(wkb, len(wkb))
+            if ptr:
+                # Reassigning pointer, and resetting the SRID.
+                destroy_geom(self._ptr)
+                self._ptr = ptr
+                self.srid = g.srid
+        else:
+            pass
+
     #### Topology Routines ####
     def _topology(self, gptr):
         "Helper routine to return Geometry from the given pointer."

django/contrib/gis/tests/test_geos.py

@@ -78,6 +78,16 @@ class GEOSTest(unittest.TestCase):
             # we need to do this so decimal places get normalised
             geom_t = fromstr(g.wkt)
             self.assertEqual(geom_t.wkt, geom_h.wkt)
+
+    def test01h_ewkt(self):
+        "Testing EWKT."
+        srid = 32140
+        for p in polygons:
+            ewkt = 'SRID=%d;%s' % (srid, p.wkt)
+            poly = fromstr(ewkt)
+            self.assertEqual(srid, poly.srid)
+            self.assertEqual(srid, poly.shell.srid)
+            self.assertEqual(srid, fromstr(poly.ewkt).srid) # Checking export
     
     def test02a_points(self):
         "Testing Point objects."