gis: gdal: cleaned up the error module; got rid of relative imports in __init__; added the utility functions get_fields() and get_geoms() to Layer.

git-svn-id: http://code.djangoproject.com/svn/django/branches/gis@6059 bcc190cf-cafb-0310-a4f2-bffc1f526a37

django/contrib/gis/gdal/__init__.py

@@ -1,8 +1,8 @@
-from driver import Driver
-from envelope import Envelope
-from datasource import DataSource
-from srs import SpatialReference, CoordTransform
-from geometries import OGRGeometry
-from geomtype import OGRGeomType
-from error import check_err, OGRException, SRSException
+from django.contrib.gis.gdal.driver import Driver
+from django.contrib.gis.gdal.envelope import Envelope
+from django.contrib.gis.gdal.datasource import DataSource
+from django.contrib.gis.gdal.srs import SpatialReference, CoordTransform
+from django.contrib.gis.gdal.geometries import OGRGeometry
+from django.contrib.gis.gdal.geomtype import OGRGeomType
+from django.contrib.gis.gdal.error import check_err, OGRException, SRSException
 

django/contrib/gis/gdal/error.py

@@ -1,35 +1,31 @@
-# OGR Error Codes
-OGRERR_NONE = 0
-OGRERR_NOT_ENOUGH_DATA = 1
-OGRERR_NOT_ENOUGH_MEMORY = 2
-OGRERR_UNSUPPORTED_GEOMETRY_TYPE = 3
-OGRERR_UNSUPPORTED_OPERATION = 4
-OGRERR_CORRUPT_DATA = 5
-OGRERR_FAILURE = 6
-OGRERR_UNSUPPORTED_SRS = 7
+"""
+  This module houses the OGR & SRS Exception objects, and the
+   check_err() routine which checks the status code returned by
+   OGR methods.
+"""
 
 # OGR & SRS Exceptions
 class OGRException(Exception): pass
 class SRSException(Exception): pass
 
-def check_err(code, msg=False):
-    "Checks the given OGRERR, and raises an exception where appropriate."
+# OGR Error Codes
+OGRERR_DICT = { 1 : (OGRException, 'Not enough data.'),
+                2 : (OGRException, 'Not enough memory.'),
+                3 : (OGRException, 'Unsupported geometry type.'),
+                4 : (OGRException, 'Unsupported operation.'),
+                5 : (OGRException, 'Corrupt data.'),
+                6 : (OGRException, 'OGR failure.'),
+                7 : (SRSException, 'Unsupported SRS.'),
+                }
+OGRERR_NONE = 0
 
+def check_err(code):
+    "Checks the given OGRERR, and raises an exception where appropriate."
+    
     if code == OGRERR_NONE:
         return
-    elif code == OGRERR_NOT_ENOUGH_DATA:
-        raise OGRException, 'Not enough data!'
-    elif code == OGRERR_NOT_ENOUGH_MEMORY:
-        raise OGRException, 'Not enough memory!'
-    elif code == OGRERR_UNSUPPORTED_GEOMETRY_TYPE:
-        raise OGRException, 'Unsupported Geometry Type!'
-    elif code == OGRERR_UNSUPPORTED_OPERATION:
-        raise OGRException, 'Unsupported Operation!'
-    elif code == OGRERR_CORRUPT_DATA:
-        raise OGRException, 'Corrupt Data!'
-    elif code == OGRERR_FAILURE:
-        raise OGRException, 'OGR Failure!'
-    elif code == OGRERR_UNSUPPORTED_SRS:
-        raise SRSException, 'Unsupported SRS!'
+    elif code in OGRERR_DICT:
+        e, msg = OGRERR_DICT[code]
+        raise e, msg
     else:
-        raise OGRException, 'Unknown error code: "%s"' % str(code)
+        raise OGRException, 'Unknown error code: "%s"' % code

django/contrib/gis/gdal/layer.py

@@ -112,3 +112,19 @@ class Layer(object):
         return [ string_at(lgdal.OGR_Fld_GetNameRef(lgdal.OGR_FD_GetFieldDefn(self._ldefn, i)))
                  for i in xrange(self.num_fields) ]
     
+    #### Layer Methods ####
+    def get_fields(self, field_name):
+        """Returns a list containing the given field name for every Feature
+        in the Layer."""
+        if not field_name in self.fields:
+            raise OGRException, 'invalid field name: %s' % field_name
+        return [feat.get(field_name) for feat in self]
+
+    def get_geoms(self, geos=False):
+        """Returns a list containing the OGRGeometry for every Feature in
+        the Layer."""
+        if geos:
+            from django.contrib.gis.geos import fromstr
+            return [fromstr(feat.geom.wkt) for feat in self]
+        else:
+            return [feat.geom for feat in self]