Detect what each auto boundary is bordered by, and try filtering based

on it

backend/src/auto_boundaries.rs

@@ -1,4 +1,4 @@
-use geo::{Area, Coord, LineString, Polygon};
+use geo::{Area, Coord, Intersects, LineString, Polygon};
 use geojson::FeatureCollection;
 use i_float::f64_point::F64Point;
 use i_overlay::core::fill_rule::FillRule;
@@ -11,6 +11,7 @@ impl MapModel {
     pub fn render_auto_boundaries(&self) -> FeatureCollection {
         let mut features = Vec::new();
         let mut severances = Vec::new();
+        let mut road_severances = Vec::new();
 
         for road in &self.roads {
             if road.tags.is_any(
@@ -32,6 +33,7 @@ impl MapModel {
                 features.push(f);
 
                 severances.push(road.linestring.clone());
+                road_severances.push(road.linestring.clone());
             }
         }
 
@@ -52,8 +54,16 @@ impl MapModel {
         }
 
         for polygon in split_polygon(self.mercator.to_mercator(&self.boundary_wgs84), severances) {
+            // TODO This is expensive; could this info somehow be retained?
+            let touches_big_road = boundary_touches_any(&polygon, &road_severances);
+            let touches_railway = boundary_touches_any(&polygon, &self.railways);
+            let touches_waterway = boundary_touches_any(&polygon, &self.waterways);
+
             let mut f = self.mercator.to_wgs84_gj(&polygon);
             f.set_property("kind", "area");
+            f.set_property("touches_big_road", touches_big_road);
+            f.set_property("touches_railway", touches_railway);
+            f.set_property("touches_waterway", touches_waterway);
             // Convert from m^2 to km^2. Use unsigned area to ignore polygon orientation.
             f.set_property("area_km2", polygon.unsigned_area() / 1_000_000.0);
             features.push(f);
@@ -103,3 +113,10 @@ fn to_geo_linestring(pts: Vec<F64Point>) -> LineString {
             .collect(),
     )
 }
+
+fn boundary_touches_any(polygon: &Polygon, linestrings: &Vec<LineString>) -> bool {
+    // TODO At least consider an rtree to prune!
+    linestrings
+        .iter()
+        .any(|ls| ls.intersects(polygon.exterior()))
+}

backend/src/scrape.rs

@@ -61,7 +61,9 @@ pub fn scrape_osm(
                         node_ids.into_iter().map(|n| node_mapping[&n]).collect(),
                     ));
                 }
-            } else if tags.is_any("natural", vec!["water", "coastline"]) {
+            } else if tags.is_any("natural", vec!["water", "coastline"])
+                || tags.is("waterway", "dock")
+            {
                 // If the entire area is inside the study area, the LineString will be closed. If
                 // it intersects the study area, then it might not be.
                 node_ids.retain(|n| node_mapping.contains_key(n));

web/src/AutoBoundariesMode.svelte

@@ -7,6 +7,7 @@
     hoverStateFilter,
     type LayerClickInfo,
   } from "svelte-maplibre";
+  import type { ExpressionSpecification } from "maplibre-gl";
   import { Link, Popup, layerId } from "./common";
   import { isLine, isPolygon } from "svelte-utils/map";
   import { SplitComponent } from "svelte-utils/top_bar_layout";
@@ -15,6 +16,7 @@
 
   let gj = JSON.parse($app!.renderAutoBoundaries());
   let minArea = 0;
+  let removeNonRoad = true;
 
   function add(e: CustomEvent<LayerClickInfo>) {
     let name = window.prompt("What do you want to name the neighbourhood?");
@@ -49,6 +51,17 @@
       JSON.stringify(gj, null, "  "),
     );
   }
+
+  function makeFilter(
+    minArea: number,
+    removeNonRoad: boolean,
+  ): ExpressionSpecification {
+    let x: ExpressionSpecification = ["all", isPolygon, [">=", ["get", "area_km2"], minArea]];
+    if (removeNonRoad) {
+      x.push(["get", "touches_big_road"]);
+    }
+    return x;
+  }
 </script>
 
 <SplitComponent>
@@ -85,13 +98,18 @@
       Minimum area (km²)
       <input type="number" bind:value={minArea} min="0" max="1" step="0.01" />
     </label>
+
+    <label>
+      <input type="checkbox" bind:checked={removeNonRoad} />
+      Remove areas not touching a big road
+    </label>
   </div>
 
   <div slot="map">
     <GeoJSON data={gj} generateId>
       <FillLayer
         {...layerId("auto-boundaries-areas")}
-        filter={["all", isPolygon, [">=", ["get", "area_km2"], minArea]]}
+        filter={makeFilter(minArea, removeNonRoad)}
         manageHoverState
         paint={{
           "fill-color": [
@@ -115,7 +133,11 @@
         hoverCursor="pointer"
       >
         <Popup openOn="hover" let:props>
-          Area: {props.area_km2.toFixed(5)} km²
+          <p>Area: {props.area_km2.toFixed(1)} km²</p>
+          <p>
+            Borders roads = {props.touches_big_road}, railway = {props.touches_railway},
+            water = {props.touches_waterway}
+          </p>
         </Popup>
       </FillLayer>