Import overlapping constituencies

hub/management/commands/import_new_constituencies.py

@@ -4,9 +4,11 @@
 from django.core.management.base import BaseCommand
 from django.db.utils import IntegrityError
 
+from mysoc_dataset import get_dataset_df
 from tqdm import tqdm
 
-from hub.models import Area, AreaType
+from hub.models import Area, AreaOverlap, AreaType
+from utils.constituency_mapping import get_overlap_df
 
 
 class Command(BaseCommand):
@@ -57,3 +59,30 @@ def handle(self, quiet: bool = False, *args, **options):
             con["properties"]["type"] = "WMC23"
             a.geometry = json.dumps(con)
             a.save()
+
+        constituency_lookup = (
+            get_dataset_df(
+                repo_name="2025-constituencies",
+                package_name="parliament_con_2025",
+                version_name="latest",
+                file_name="parl_constituencies_2025.csv",
+            )
+            .set_index("short_code")["gss_code"]
+            .to_dict()
+        )
+
+        df = get_overlap_df("PARL10", "PARL25")
+        for area in Area.objects.filter(area_type__code="WMC"):
+            overlap_constituencies = df.query("PARL10 == @area.gss")
+            for _, row in overlap_constituencies.iterrows():
+                new_area = Area.objects.get(
+                    area_type__code="WMC23", gss=constituency_lookup[row["PARL25"]]
+                )
+                AreaOverlap.objects.get_or_create(
+                    area_old=area,
+                    area_new=new_area,
+                    defaults={
+                        "population_overlap": int(row["percentage_overlap_pop"] * 100),
+                        "area_overlap": int(row["percentage_overlap_area"] * 100),
+                    },
+                )

hub/migrations/0058_areaoverlap_area_overlaps.py

@@ -0,0 +1,51 @@
+# Generated by Django 4.2.5 on 2023-11-14 11:15
+
+from django.db import migrations, models
+import django.db.models.deletion
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ("hub", "0057_populate_dataset_areas_available"),
+    ]
+
+    operations = [
+        migrations.CreateModel(
+            name="AreaOverlap",
+            fields=[
+                (
+                    "id",
+                    models.BigAutoField(
+                        auto_created=True,
+                        primary_key=True,
+                        serialize=False,
+                        verbose_name="ID",
+                    ),
+                ),
+                ("population_overlap", models.SmallIntegerField(default=0)),
+                ("area_overlap", models.SmallIntegerField(default=0)),
+                (
+                    "area_new",
+                    models.ForeignKey(
+                        on_delete=django.db.models.deletion.CASCADE,
+                        related_name="new_overlaps",
+                        to="hub.area",
+                    ),
+                ),
+                (
+                    "area_old",
+                    models.ForeignKey(
+                        on_delete=django.db.models.deletion.CASCADE,
+                        related_name="old_overlaps",
+                        to="hub.area",
+                    ),
+                ),
+            ],
+        ),
+        migrations.AddField(
+            model_name="area",
+            name="overlaps",
+            field=models.ManyToManyField(through="hub.AreaOverlap", to="hub.area"),
+        ),
+    ]

hub/models.py

@@ -502,6 +502,7 @@
     name = models.CharField(max_length=200)
     area_type = models.ForeignKey(AreaType, on_delete=models.CASCADE)
     geometry = models.TextField(blank=True, null=True)
+    overlaps = models.ManyToManyField("self", through="AreaOverlap")
 
     def __str__(self):
         return self.name
@@ -535,17 +536,28 @@
 
     @classmethod
     def get_by_name(cls, name, area_type="WMC"):
         try:
             area = cls.objects.get(name__iexact=name, area_type__code=area_type)
         except cls.DoesNotExist:
             area = None
 
         return area
 
     class Meta:
         unique_together = ["gss", "area_type"]
 
 
+class AreaOverlap(models.Model):
+    area_old = models.ForeignKey(
+        Area, on_delete=models.CASCADE, related_name="old_overlaps"
+    )
+    area_new = models.ForeignKey(
+        Area, on_delete=models.CASCADE, related_name="new_overlaps"
+    )
+    population_overlap = models.SmallIntegerField(default=0)
+    area_overlap = models.SmallIntegerField(default=0)
+
+
 class AreaData(CommonData):
     area = models.ForeignKey(Area, on_delete=models.CASCADE)
 

hub/templates/hub/area.html

@@ -41,24 +41,43 @@ <h1 class="m-0">{{ area.name }}</h1>
                 </div>
             </div>
             <div class="col-lg-9 offset-xl-1">
-              {% if area_type == "WMC" %}
-                <div class="card flex-grow-1 dataset-card">
-                    <div class="dataset-card-header">
-                        <h2 class="h5">This is a 2010 constituency</h2>
+              {% if area_type == "WMC" and area.overlaps %}
+                <div class="card flex-grow-1">
+                    <div class="card-body">
+                      {% if overlap_constituencies|length > 1 %}
+                        <p>At the next election, this constituency will be divided into <b>{{ overlap_constituencies|length|apnumber }} new constituenc{% if overlap_constituencies|length_is:1 %}y{% else %}ies{% endif %}:</b></p>
+                      {% else %}
+                        <p>At the next election, this constituency will be replaced with:</p>
+                      {% endif %}
+                        <div style="display: grid; grid-template-columns: repeat(auto-fit, minmax(14rem, 1fr)); grid-gap: 1rem 2rem;">
+                          {% for overlap_constituency in overlap_constituencies %}
+                            <div>
+                                <h3 class="h5"><a href="{% url 'area' area_type=overlap_constituency.new_area.area_type.code name=overlap_constituency.new_area.name %}" class="text-decoration-none">{{ overlap_constituency.new_area }}</a></h3>
+                                <p class="fs-7 text-muted mb-0">Will cover approximately {{ overlap_constituency.pop_overlap }}% of this constituency’s population, and {{ overlap_constituency.area_overlap }}% of this constituency’s area.</p>
+                            </div>
+                          {% endfor %}
+                        </div>
                     </div>
+                </div>
+              {% elif area_type == "WMC23" and area.overlaps %}
+                <div class="card flex-grow-1">
+                  {% if area.overlaps %}
                     <div class="card-body">
-                        <p>At the next election, people from this constituency will be divided into <b>{{ overlap_constituencies|length|apnumber }} constituenc{% if overlap_constituencies|length_is:1 %}y{% else %}ies{% endif %}:</b></p>
-                        <table class="table mb-0">
-                            <tbody>
-                              {% for overlap_constituency in overlap_constituencies %}
-                                <tr>
-                                    <th><a href="{% url 'area' area_type=overlap_constituency.area.area_type.code name=overlap_constituency.area.name %}" class="text-decoration-none">{{ overlap_constituency.area }}</a></th>
-                                    <td class="text-muted">Covers approximately {{ overlap_constituency.pop_overlap }}% of this constituency’s population, and {{ overlap_constituency.area_overlap }}% of this constituency’s area.</td>
-                                </tr>
-                              {% endfor %}
-                            </tbody>
-                        </table>
+                      {% if overlap_constituencies|length > 1 %}
+                        <p>This constituency will only exist at the next election, and replaces the previous <b>{{ overlap_constituencies|length|apnumber }} constituenc{% if overlap_constituencies|length_is:1 %}y{% else %}ies{% endif %}:</b></p>
+                      {% else %}
+                        <p>This constituency will only exist at the next election, and replaces:</p>
+                      {% endif %}
+                        <div style="display: grid; grid-template-columns: repeat(auto-fit, minmax(14rem, 1fr)); grid-gap: 1rem 2rem;">
+                          {% for overlap_constituency in overlap_constituencies %}
+                            <div>
+                                <h3 class="h5"><a href="{% url 'area' area_type=overlap_constituency.old_area.area_type.code name=overlap_constituency.old_area.name %}" class="text-decoration-none">{{ overlap_constituency.old_area }}</a></h3>
+                                <p class="fs-7 text-muted mb-0">Covered approximately {{ overlap_constituency.pop_overlap }}% of this constituency’s population, and {{ overlap_constituency.area_overlap }}% of this constituency’s area.</p>
+                            </div>
+                          {% endfor %}
+                        </div>
                     </div>
+                  {% endif %}
                 </div>
               {% endif %}
 

hub/views/area.py

@@ -5,8 +5,6 @@
 from django.shortcuts import get_object_or_404, redirect
 from django.views.generic import DetailView, TemplateView, View
 
-from mysoc_dataset import get_dataset_df
-
 from hub.mixins import TitleMixin
 from hub.models import (
     Area,
@@ -18,7 +16,6 @@
     UserDataSets,
 )
 from utils import is_valid_postcode
-from utils.constituency_mapping import get_overlap_df
 from utils.mapit import (
     BadRequestException,
     ForbiddenException,
@@ -180,27 +177,21 @@
         return tags
 
     def get_overlap_info(self, **kwargs):
-        # Get lookup between short code and GSS
-        constituency_lookup = (
-            get_dataset_df(
-                repo_name="2025-constituencies",
-                package_name="parliament_con_2025",
-                version_name="latest",
-                file_name="parl_constituencies_2025.csv",
-            )
-            .set_index("short_code")["gss_code"]
-            .to_dict()
-        )
+        if self.object.area_type.code == "WMC":
+            overlaps = self.object.old_overlaps.all()
+        elif self.object.area_type.code == "WMC23":
+            overlaps = self.object.new_overlaps.all()
+        else:
+            return []
 
-        df = get_overlap_df("PARL10", "PARL25")
-        overlap_constituencies = df.query("PARL10 == @self.object.gss")
         overlap_constituencies = [
             {
-                "area": Area.objects.get(gss=constituency_lookup[row["PARL25"]]),
-                "pop_overlap": int(row["percentage_overlap_pop"] * 100),
-                "area_overlap": int(row["percentage_overlap_area"] * 100),
+                "new_area": overlap.area_new,
+                "old_area": overlap.area_old,
+                "pop_overlap": overlap.population_overlap,
+                "area_overlap": overlap.area_overlap,
             }
-            for index, row in overlap_constituencies.iterrows()
+            for overlap in overlaps
         ]
         return overlap_constituencies