feat: map the complete municipality of Mol

frontend/src/lib/geojsonBounds.ts

@@ -0,0 +1,75 @@
+export interface GeoJsonBounds {
+  minX: number
+  minY: number
+  maxX: number
+  maxY: number
+}
+
+function extendBounds(bounds: GeoJsonBounds | null, x: number, y: number): GeoJsonBounds {
+  if (!bounds) {
+    return { minX: x, minY: y, maxX: x, maxY: y }
+  }
+  bounds.minX = Math.min(bounds.minX, x)
+  bounds.minY = Math.min(bounds.minY, y)
+  bounds.maxX = Math.max(bounds.maxX, x)
+  bounds.maxY = Math.max(bounds.maxY, y)
+  return bounds
+}
+
+function scanCoordinates(coordinates: unknown, initial: GeoJsonBounds | null): GeoJsonBounds | null {
+  let bounds = initial
+  const stack: unknown[] = [coordinates]
+  while (stack.length > 0) {
+    const value = stack.pop()
+    if (!Array.isArray(value)) {
+      continue
+    }
+    if (value.length >= 2 && typeof value[0] === 'number' && typeof value[1] === 'number') {
+      if (Number.isFinite(value[0]) && Number.isFinite(value[1])) {
+        bounds = extendBounds(bounds, value[0], value[1])
+      }
+      continue
+    }
+    for (const child of value) {
+      stack.push(child)
+    }
+  }
+  return bounds
+}
+
+export function geometryBounds(geometry: GeoJSON.Geometry | null | undefined): GeoJsonBounds | null {
+  if (!geometry) {
+    return null
+  }
+  if (geometry.type === 'GeometryCollection') {
+    return geometry.geometries.reduce<GeoJsonBounds | null>(
+      (bounds, child) => mergeBounds(bounds, geometryBounds(child)),
+      null,
+    )
+  }
+  return scanCoordinates(geometry.coordinates, null)
+}
+
+export function mergeBounds(left: GeoJsonBounds | null, right: GeoJsonBounds | null): GeoJsonBounds | null {
+  if (!left) {
+    return right ? { ...right } : null
+  }
+  if (!right) {
+    return left
+  }
+  left.minX = Math.min(left.minX, right.minX)
+  left.minY = Math.min(left.minY, right.minY)
+  left.maxX = Math.max(left.maxX, right.maxX)
+  left.maxY = Math.max(left.maxY, right.maxY)
+  return left
+}
+
+export function featureCollectionBounds(collection: GeoJSON.FeatureCollection | null | undefined): GeoJsonBounds | null {
+  if (!collection) {
+    return null
+  }
+  return collection.features.reduce<GeoJsonBounds | null>(
+    (bounds, feature) => mergeBounds(bounds, geometryBounds(feature.geometry)),
+    null,
+  )
+}