Changes between Version 32 and Version 33 of GeoDjango

Timestamp:

Mar 11, 2007, 7:01:03 PM (17 years ago)

Author:

jbronn

Comment:

--

GeoDjango

@@ -37 +37 @@
 
 == Phase 1 ==
-  Assume existing data and columns, and that the UOM given is same as backing data.
-  Support a custom manager (and queryset) to support lookups.
+ * Create Geometry-enabled fields and manager.  Status: complete (not yet in SVN).
+ * Allow for Geometry-enabled queries.  Status: complete (not yet in SVN).
+ * Here is an example of how the model API currently works (assume this example is in geo_app/models.py):
 
-=== GeoTypes ===
-  GeoTypes 0.7 supports both psycopg1 and psycopg2.  Upside is conversion from type params to SQL.  Simplifies (avoids?) QuerySet modification.  Maintainer of GeoTypes has been responsive as of Feb 26 2007 on the psycopg mailing list.
-  Example code, where point and box are types from GeoTypes.OG*:
 {{{
-from django.db import models
-from django.contrib.gis import db as gis_db
+from django.contrib.gis.db import models
 
-class School(meta.Model):
-  name = ...
-  objects = gis_db.Manager()
+class District(models.Model):
+    name = models.CharField(maxlength=35)
+    num  = models.IntegerField()
+    poly = models.MultiPolygonField()
 
-Assume a location column has already been added to the DB, e.g.
-select addgeometrycolumn('','schools_school','location',-1, 'POINT', 2);
+    objects = models.GeoManager()
 
-Then this would work:
-from django.contrib.gis.geometry import Point
-x = Point(-95.36819458007812, 30.2184318620219)
-School.objects.geo_near('location', point=x, radius=1.0)
+class School(models.Model):
+    name  = models.CharField(maxlength=35)
+    point = models.PointField()
 
-This could construct a LinearRing approximating the circle around x
-and issue something like:
-
-poly = "POLYGON (...points from curve approximation...)"
-_where.append("""
-where schools_school.location && %s and
-within(schools_school.location, %s)
-""")
-_params.append(poly, poly)
+    objects = models.GeoManager()
 }}}
 
-=== Geos ===
-  I'm not sure how we can use GEOS without also doing something like GeoTypes down in the QuerySet.  Ideas?
+ * Use the manage.py just like you normally would:
 
+{{{
+$ python manage.py sqlall geo_app
+BEGIN;
+CREATE TABLE "geo_app_school" (
+    "id" serial NOT NULL PRIMARY KEY,
+    "name" varchar(35) NOT NULL
+);
+CREATE TABLE "geo_app_district" (
+    "id" serial NOT NULL PRIMARY KEY,
+    "name" varchar(35) NOT NULL,
+    "num" integer NOT NULL
+);
+SELECT AddGeometryColumn('geo_app_school', 'point', 4326, 'POINT', 2);
+SELECT AddGeometryColumn('geo_app_district', 'poly', 4326, 'MULTIPOLYGON', 2);
+COMMIT;
+$ python manage.py syncdb geo_app
 
+}}}
+
+  * PostGIS additions to the API may now be used:
+
+{{{
+>>> from geo_app.models import District, School
+>>> qs1 = District.objects.filter(poly__bbcontains='POINT(-95.362293 29.756539)') # Same as PostGIS '&&' operator
+>>> qs2 = District.objects.filter(poly__intersects='POINT(-95.362293 29.756539)') # Same as PostGIS Intersects() (from GEOS)
+
+}}}
 
 == Phase 2 ==
-=== Field Types ===
- * To allow update through ORM, new fieldtypes would be needed.
-
-
-=== GIS utilities ===
-wrapper for geos, have the ability to do something like
-
-{{{
-from django.contrib.gis import area
-area(bbox.geom)
-}}}
+ * Add as much from the PostGIS as possible.
+ * Add geometry-enabled routines to the fields that call directly on GEOS routines -- like area(), centroid(), etc.
+ * Contemplate a JS framework for mapping.  I know Django community is against including any type of JS/AJAX framework, but having a way to generate maps would be a great addition.  Also, any type of framework would be limited to the contrib package only.
 
 = Installation =