From c35a05c8149048eb91c859166f07bc7770415c70 Mon Sep 17 00:00:00 2001
From: Yorick de Wid <yorickdewid@users.noreply.github.com>
Date: Sun, 26 Jul 2026 21:18:48 +0000
Subject: [PATCH] feat(layers): add HotSpot layer to the Risico mapset

Closes #919. A HotSpot is a building whose highest risk class across the
two groundwater-driven models is D or E:

    MAX(drystand_risk, dewatering_depth_risk) >= 'd'

The classes order a < b < c < d < e, so "the maximum" is the worse of the
two; A/B/C are excluded. It answers "where do we look first" at a glance,
it is not a new model.

No data work: maplayer.building_tiles already carries both columns and
maplayer.buildings(z,x,y) emits both at every zoom (z12-13 included), so
the layer is purely a filter + paint expression over the existing
'buildings' source. address_count != 0 matches the other risk layers.

Colored by the worst of the two classes, reusing the exact D and E
swatches of the drystand-risk / dewatering-depth-risk legends so HotSpot
reads as a summary of those two rather than a separate scale.

Verified against @maplibre/maplibre-gl-style-spec, and by compiling the
filter and color expressions and evaluating all 108 combinations of
(drystand, dewatering) x {null,a..e} x address_count {0,1,4} against the
spec table. The absent-attribute cases matter: 3.6M buildings have no
drystand_risk, and MVT drops null attributes entirely.

The matching legend row lives in FunderMapsWorker
sql/migrate/add_hotspot_layer.sql and must be applied AFTER this ships -
the other order leaves a layer id in layerSet that has no config here.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
---
 src/config/layers/hotspot.json | 55 ++++++++++++++++++++++++++++++++++
 1 file changed, 55 insertions(+)
 create mode 100644 src/config/layers/hotspot.json

diff --git a/src/config/layers/hotspot.json b/src/config/layers/hotspot.json
new file mode 100644
index 0000000..5d02b27
--- /dev/null
+++ b/src/config/layers/hotspot.json
@@ -0,0 +1,55 @@
+{
+  "id": "hotspot",
+  "type": "fill-extrusion",
+  "source": "buildings",
+  "source-layer": "buildings",
+  "filter": [
+      "all",
+      [
+          "any",
+          [
+              "match",
+              ["get", "drystand_risk"],
+              ["d", "e"],
+              true,
+              false
+          ],
+          [
+              "match",
+              ["get", "dewatering_depth_risk"],
+              ["d", "e"],
+              true,
+              false
+          ]
+      ],
+      ["!=", ["get", "address_count"], 0]
+  ],
+  "layout": {"visibility": "none"},
+  "paint": {
+      "fill-extrusion-height": [
+          "interpolate",
+          ["linear"],
+          ["zoom"],
+          0,
+          ["get", "height"],
+          22,
+          ["get", "height"]
+      ],
+      "fill-extrusion-color": [
+          "case",
+          [
+              "any",
+              ["==", ["get", "drystand_risk"], "e"],
+              ["==", ["get", "dewatering_depth_risk"], "e"]
+          ],
+          "#ff5533",
+          [
+              "any",
+              ["==", ["get", "drystand_risk"], "d"],
+              ["==", ["get", "dewatering_depth_risk"], "d"]
+          ],
+          "#ffac33",
+          "hsla(0, 0%, 0%, 0)"
+      ]
+  }
+}