[UK] Use database for co-ordinate transformation.

mapit/management/commands/mapit_import_postal_codes.py

@@ -131,17 +131,12 @@ def do_postcode(self, location=None, srid=None):
             pc = Postcode.objects.get(postcode=self.code)
             if location:
                 if pc.location:
-                    curr_location = (pc.location[0], pc.location[1])
+                    curr_location = pc.location
+                    # Postcode locations are stored as WGS84
                     if settings.MAPIT_COUNTRY == 'GB':
-                        if pc.postcode[0:2] == 'BT':
-                            curr_location = pc.as_irish_grid()
-                        else:
-                            pc.location.transform(27700)  # Postcode locations are stored as WGS84
-                            curr_location = (pc.location[0], pc.location[1])
-                        curr_location = tuple(map(round, curr_location))
+                        curr_location = pc.as_uk_grid()
                     elif srid != 4326:
-                        pc.location.transform(srid)  # Postcode locations are stored as WGS84
-                        curr_location = (pc.location[0], pc.location[1])
+                        curr_location = pc.location.transform(srid, clone=True)
                     if curr_location[0] != location[0] or curr_location[1] != location[1]:
                         pc.location = location
                         pc.save()

mapit/models.py

@@ -413,6 +413,10 @@ def filter_by_area(self, area):
         )
 
 
+def str2int(s):
+    return int(round(float(s)))
+
+
 @python_2_unicode_compatible
 class Postcode(models.Model):
     postcode = models.CharField(max_length=7, db_index=True, unique=True)
@@ -449,12 +453,13 @@ def as_dict(self):
             countries.augment_postcode(self, result)
         return result
 
-    # Doing this via self.location.transform(29902) gives incorrect results.
-    # The database has the right proj4 text, the proj file does not. I think.
-    def as_irish_grid(self):
+    # Doing this via self.location.transform(27700/29902) can give incorrect results
+    # with some versions of GDAL. Via the database produces a correct result.
+    def as_uk_grid(self):
         cursor = connection.cursor()
-        cursor.execute("SELECT ST_AsText(ST_Transform(ST_GeomFromText('POINT(%f %f)', 4326), 29902))" % (
-            self.location[0], self.location[1]))
+        srid = 29902 if self.postcode[0:2] == 'BT' else 27700
+        cursor.execute("SELECT ST_AsText(ST_Transform(ST_GeomFromText('POINT(%f %f)', 4326), %d))" % (
+            self.location[0], self.location[1], srid))
         row = cursor.fetchone()
         m = re.match('POINT\((.*?) (.*)\)', row[0])
-        return list(map(float, m.groups()))
+        return list(map(str2int, m.groups()))

mapit/templates/mapit/postcode.html

@@ -13,7 +13,7 @@ <h2>{{ postcode.postcode }}</h2>
         E/N: {{ postcode.easting }}, {{ postcode.northing }}
       {% endif %}
       {% if postcode.wgs84_lat or postcode.wgs84_lon %}
-        <li>{% trans "WGS84 lat/lon" %}: <a href="https://tools.wmflabs.org/geohack/geohack.php?params={{ postcode.wgs84_lat|floatformat }};{{ postcode.wgs84_lon }}">{{ postcode.wgs84_lat }}, {{ postcode.wgs84_lon }}</a>
+        <li>{% trans "WGS84 lat/lon" %}: <a href="https://tools.wmflabs.org/geohack/geohack.php?params={{ postcode.wgs84_lat|floatformat:-6 }};{{ postcode.wgs84_lon|floatformat:-6 }}">{{ postcode.wgs84_lat|floatformat:-6 }}, {{ postcode.wgs84_lon|floatformat:-6 }}</a>
       {% else %}
         <li>{% blocktrans trimmed %}
     No location information. Note this <em>is</em> a valid postcode (otherwise you would have got a 404), just one for which we don&rsquo;t know the location.
@@ -36,7 +36,7 @@ <h2>{{ postcode.postcode }}</h2>
         maxZoom: 18
     });
 
-    var point = new L.LatLng({{ postcode.wgs84_lat }}, {{ postcode.wgs84_lon }});
+    var point = new L.LatLng({{ postcode.wgs84_lat|floatformat:-6 }}, {{ postcode.wgs84_lon|floatformat:-6 }});
     var marker = new L.Marker(point);
     map.addLayer(marker);
     map.setView(point, 14);

mapit/tests/test_names.py

@@ -41,14 +41,18 @@ def setUp(self):
     def test_new_name_changes_area_name_in_gb(self):
         """We can't use override_settings, as mapit.countries has been set
         based upon MAPIT_COUNTRY already in initial import"""
+        orig_countries = mapit.models.countries
         mapit.models.countries = mapit_gb.countries
         Name.objects.create(name='New Name (B)', type=self.name_type, area=self.area)
         self.assertEqual(self.area.name, 'New Name Borough')
+        mapit.models.countries = orig_countries
 
     def test_new_name_does_not_change_area_name_elsewhere(self):
+        orig_countries = mapit.models.countries
         mapit.models.countries = None
         Name.objects.create(name='New Name', type=self.name_type, area=self.area)
         self.assertEqual(self.area.name, 'Big Area')
+        mapit.models.countries = orig_countries
 
     def test_geometry_name_works(self):
         name = smart_text('Big “Area”')

mapit/tests/test_views.py

@@ -1,13 +1,12 @@
 import json
+import unittest
 
 from django.test import TestCase
 from django.conf import settings
 from django.contrib.gis.geos import Polygon, Point
 
 from mapit.models import Type, Area, Geometry, Generation, Postcode
 from mapit.tests.utils import get_content
-import mapit_gb.countries
-import mapit.views
 
 
 class AreaViewsTest(TestCase):
@@ -89,8 +88,8 @@ def test_front_page(self):
         response = self.client.get('/')
         self.assertContains(response, 'MapIt')
 
+    @unittest.skipUnless(settings.MAPIT_COUNTRY == 'GB', 'UK only test')
     def test_postcode_submission(self):
-        mapit.views.countries = mapit_gb.countries
         response = self.client.post('/postcode/', {'pc': 'PO14 1NT'}, follow=True)
         self.assertRedirects(response, '/postcode/PO141NT.html')
         response = self.client.post('/postcode/', {'pc': 'PO141NT.'}, follow=True)
@@ -107,7 +106,7 @@ def test_example_postcode(self):
         url = '/area/%d/example_postcode' % id
         response = self.client.get(url)
         content = get_content(response)
-        self.assertEqual(content, self.postcode.postcode)
+        self.assertEqual(content, str(self.postcode))
 
     def test_nearest_with_bad_srid(self):
         url = '/nearest/84/0,0.json'

mapit_gb/countries.py

@@ -81,15 +81,10 @@ def augment_postcode(postcode, result):
     pc = postcode.postcode
     if is_special_postcode(pc):
         return
-    if pc[0:2] == 'BT':
-        loc = postcode.as_irish_grid()
-        result['coordsyst'] = 'I'
-    else:
-        loc = postcode.location
-        loc.transform(27700)
-        result['coordsyst'] = 'G'
-    result['easting'] = int(round(loc[0]))
-    result['northing'] = int(round(loc[1]))
+    loc = postcode.as_uk_grid()
+    result['coordsyst'] = 'I' if pc[0:2] == 'BT' else 'G'
+    result['easting'] = loc[0]
+    result['northing'] = loc[1]
 
 
 # Hacky function to restrict certain geographical links in the HTML pages to

mapit_gb/tests.py

@@ -1,3 +1,4 @@
+import unittest
 from django.conf import settings
 from django.test import TestCase
 from django.contrib.gis.geos import Polygon, Point
@@ -16,8 +17,8 @@ def url_postcode(pc):
 class GBViewsTest(TestCase):
     def setUp(self):
         # Make sure we're using the GB postcode functions here
-        models.countries = countries
-        utils.countries = countries
+        self.orig_countries = models.countries
+        models.countries = utils.countries = countries
 
         self.postcode = models.Postcode.objects.create(
             postcode='SW1A1AA',
@@ -67,21 +68,30 @@ def setUp(self):
             code='E05000025',
         )
 
+    def tearDown(self):
+        models.countries = utils.countries = self.orig_countries
+
+    def test_ni_postcode(self):
+        postcode = models.Postcode(postcode='BT170XD', location=Point(-6.037555, 54.556533))
+        grid = postcode.as_uk_grid()
+        self.assertEqual(grid, [327011, 369351])
+
     def test_postcode_json(self):
         pc = self.postcode.postcode
         url = '/postcode/%s' % urllib.parse.quote(pc)
         response = self.client.get(url)
         content = get_content(response)
 
-        in_gb_coords = self.postcode.location.transform(27700, clone=True)
+        in_gb_coords = self.postcode.as_uk_grid()
+        self.assertEqual(in_gb_coords, [529090, 179645])
         pc = countries.get_postcode_display(self.postcode.postcode)
         self.assertDictEqual(content, {
             'postcode': pc,
             'wgs84_lat': self.postcode.location.y,
             'wgs84_lon': self.postcode.location.x,
             'coordsyst': 'G',
-            'easting': round(in_gb_coords.x),
-            'northing': round(in_gb_coords.y),
+            'easting': round(in_gb_coords[0]),
+            'northing': round(in_gb_coords[1]),
             'areas': {
                 str(self.area.id): {
                     'id': self.area.id,
@@ -113,14 +123,14 @@ def test_partial_json(self):
         response = self.client.get(url)
         content = get_content(response)
         countries.get_postcode_display(self.postcode.postcode)
-        in_gb_coords = self.postcode.location.transform(27700, clone=True)
+        in_gb_coords = self.postcode.as_uk_grid()
         self.assertDictEqual(content, {
             'wgs84_lat': self.postcode.location.y,
             'wgs84_lon': self.postcode.location.x,
             'coordsyst': 'G',
             'postcode': 'SW1A',
-            'easting': round(in_gb_coords.x),
-            'northing': round(in_gb_coords.y)
+            'easting': round(in_gb_coords[0]),
+            'northing': round(in_gb_coords[1])
         })
 
     def test_partial_json_link(self):
@@ -133,16 +143,16 @@ def test_nearest_json(self):
         response = self.client.get(url)
         content = get_content(response)
         pc = countries.get_postcode_display(self.postcode.postcode)
-        in_gb_coords = self.postcode.location.transform(27700, clone=True)
+        in_gb_coords = self.postcode.as_uk_grid()
         self.assertDictEqual(content, {
             'postcode': {
                 'distance': 0,
                 'wgs84_lat': self.postcode.location.y,
                 'wgs84_lon': self.postcode.location.x,
                 'coordsyst': 'G',
                 'postcode': pc,
-                'easting': round(in_gb_coords.x),
-                'northing': round(in_gb_coords.y)
+                'easting': round(in_gb_coords[0]),
+                'northing': round(in_gb_coords[1])
             }
         })
 
@@ -152,6 +162,7 @@ def test_nearest_json_link(self):
         pc = self.postcode.postcode
         self.assertContains(response, '"/postcode/%s"' % url_postcode(pc))
 
+    @unittest.skipUnless(settings.MAPIT_COUNTRY == 'GB', 'UK only tests')
     def test_gss_code(self):
         response = self.client.get('/area/E05000025')
         self.assertRedirects(response, '/area/%d' % self.area.id)