Adding Type hotspots to API

server/api/code/lacity_data_api/models/geometry.py

@@ -47,3 +47,35 @@ async def get_enclosing_council(cls, latitude: float, longitude: float):
             ).gino.first()
         )
         return result
+
+    @classmethod
+    async def get_hotspots(cls, type_id: int, start_date: str):
+
+        # using ~30m radius (epsilon) and 1+ request/month
+        query = db.text(f"""
+            SELECT
+                h.hotspot_id,
+                count(*) as hotspot_count,
+                ST_X(ST_Centroid(ST_Collect(h.request_point))) as hotspot_long,
+                ST_Y(ST_Centroid(ST_Collect(h.request_point))) as hotspot_lat
+            FROM (
+                SELECT
+                    ST_SetSRID(
+                        ST_MakePoint(longitude, latitude), 4326
+                    ) as request_point,
+                    ST_ClusterDBSCAN(
+                        ST_SetSRID(ST_MakePoint(longitude, latitude), 4326),
+                        eps := 0.0003, minpoints := 12
+                    ) over () AS hotspot_id
+                FROM
+                    service_requests
+                WHERE
+                    created_date >= '{start_date}' AND type_id = {type_id}
+            ) as h
+            WHERE hotspot_id is not null
+            GROUP BY h.hotspot_id
+            ;
+        """)
+
+        result = await db.all(query)
+        return result

server/api/code/lacity_data_api/routers/geojson.py

@@ -1,5 +1,6 @@
 import json
 
+import pendulum
 from fastapi import APIRouter, HTTPException
 
 from ..models.geometry import Geometry
@@ -20,6 +21,24 @@ def createFeature(row):
     }
 
 
+def createHotspotFeature(row):
+    item = dict(row)
+    return {
+        "type": "Feature",
+        "properties": {
+            "hotspot_id": item['hotspot_id'],
+            "count": item['hotspot_count'],
+        },
+        "geometry": {
+            "type": "Point",
+            "coordinates": [
+                item['hotspot_long'],
+                item['hotspot_lat']
+            ]
+        }
+    }
+
+
 @router.get("")
 async def get_all_geometries():
     result = await Geometry.get_council_geojson()
@@ -43,3 +62,21 @@ async def get_enclosing_council(
     if not result:
         raise HTTPException(status_code=404, detail="Item not found")
     return result
+
+
+@router.get("/hotspots")
+async def get_hotspots(
+    type_id: int = 6,  # defaults to illegal dumping
+    start_date: str = pendulum.today().subtract(years=1).to_date_string()
+):
+
+    features = []
+    result = await Geometry.get_hotspots(type_id, start_date)
+
+    for i in result:
+        features.append(createHotspotFeature(i))
+
+    return {
+        "type": "FeatureCollection",
+        "features": features
+    }