Add OSM elevation to point POIs

tiles/src/main/java/com/protomaps/basemap/layers/Pois.java

@@ -25,10 +25,15 @@
 import com.protomaps.basemap.names.OsmNames;
 import java.util.List;
 import java.util.Map;
+import java.util.regex.Pattern;
 
 @SuppressWarnings("java:S1192")
 public class Pois implements ForwardingProfile.LayerPostProcessor {
 
+  // Matches numeric metre values with an optional trailing "m" suffix, e.g. "569", "569.5", "569 m", or "569m".
+  private static final Pattern ELEVATION_PATTERN =
+    Pattern.compile("^([+-]?(?:\\d+(?:\\.\\d+)?|\\.\\d+))(?:\\s*m)?$");
+
   private Map<String, int[][]> qrankGrading = Map.of(
     "station", new int[][]{{10, 50000}, {12, 20000}, {13, 10000}},
     "aerodrome", new int[][]{{10, 50000}, {12, 20000}, {13, 5000}, {14, 2500}},
@@ -46,6 +51,25 @@ public Pois(QrankDb qrankDb) {
 
   public static final String LAYER_NAME = "pois";
 
+  static Integer parseElevation(String elevation) {
+    if (elevation == null) {
+      return null;
+    }
+
+    var matcher = ELEVATION_PATTERN.matcher(elevation.trim());
+    if (!matcher.matches()) {
+      return null;
+    }
+
+    var parsed = parseDoubleOrNull(matcher.group(1));
+    if (parsed == null) {
+      return null;
+    }
+
+    var rounded = Math.round(parsed);
+    return rounded >= Integer.MIN_VALUE && rounded <= Integer.MAX_VALUE ? (int) rounded : null;
+  }
+
   private static final Expression WITH_OPERATOR_USFS = with("operator", "United States Forest Service",
     "US Forest Service", "U.S. Forest Service", "USDA Forest Service", "United States Department of Agriculture",
     "US National Forest Service", "United State Forest Service", "U.S. National Forest Service");
@@ -501,9 +525,7 @@ public void processOsm(SourceFeature sf, FeatureCollector features) {
 
     // Assign outputFeature
     if (hasNamedPolygon) {
-      outputFeature = features.pointOnSurface(this.name())
-        //.setAttr("area_debug", wayArea) // DEBUG
-        .setAttr("elevation", sf.getString("ele"));
+      outputFeature = features.pointOnSurface(this.name());
     } else if (sf.isPoint()) {
       outputFeature = features.point(this.name());
     } else {
@@ -525,7 +547,8 @@ public void processOsm(SourceFeature sf, FeatureCollector features) {
       .setZoomRange(Math.min(minZoom, 15), 15)
       // Core OSM tags for different kinds of places
       // Special airport only tag (to indicate if it's an airport with regular commercial flights)
-      .setAttr("iata", sf.getString("iata"));
+      .setAttr("iata", sf.getString("iata"))
+      .setAttr("elevation", parseElevation(sf.getString("ele")));
 
     // Core Tilezen schema properties
     if (!kindDetail.equals("pm:undefined"))

tiles/src/test/java/com/protomaps/basemap/layers/PoisTest.java

@@ -1,6 +1,7 @@
 package com.protomaps.basemap.layers;
 
 import static com.onthegomap.planetiler.TestUtils.*;
+import static org.junit.jupiter.api.Assertions.assertFalse;
 
 import com.onthegomap.planetiler.reader.SimpleFeature;
 import java.util.HashMap;
@@ -197,6 +198,61 @@ void zoom_14_peak() {
       )));
   }
 
+  @Test
+  void peakElevation() {
+    assertFeatures(14,
+      List.of(Map.of("kind", "peak", "min_zoom", 14, "elevation", 569)),
+      process(SimpleFeature.create(
+        newPoint(1, 1),
+        new HashMap<>(Map.of("natural", "peak", "ele", "569")),
+        "osm", null, 0
+      )));
+  }
+
+  @Test
+  void peakElevationDecimal() {
+    assertFeatures(14,
+      List.of(Map.of("kind", "peak", "min_zoom", 14, "elevation", 570)),
+      process(SimpleFeature.create(
+        newPoint(1, 1),
+        new HashMap<>(Map.of("natural", "peak", "ele", "569.5")),
+        "osm", null, 0
+      )));
+  }
+
+  @Test
+  void peakElevationMeterSuffix() {
+    assertFeatures(14,
+      List.of(Map.of("kind", "peak", "min_zoom", 14, "elevation", 569)),
+      process(SimpleFeature.create(
+        newPoint(1, 1),
+        new HashMap<>(Map.of("natural", "peak", "ele", "569 m")),
+        "osm", null, 0
+      )));
+  }
+
+  @Test
+  void peakElevationMeterSuffixWithoutWhitespace() {
+    assertFeatures(14,
+      List.of(Map.of("kind", "peak", "min_zoom", 14, "elevation", 569)),
+      process(SimpleFeature.create(
+        newPoint(1, 1),
+        new HashMap<>(Map.of("natural", "peak", "ele", "569m")),
+        "osm", null, 0
+      )));
+  }
+
+  @Test
+  void peakElevationNonMeterUnitOmitted() {
+    var features = process(SimpleFeature.create(
+      newPoint(1, 1),
+      new HashMap<>(Map.of("natural", "peak", "ele", "569 ft")),
+      "osm", null, 0
+    ));
+
+    assertFalse(toMap(features.iterator().next(), 14).containsKey("elevation"));
+  }
+
   @Test
   void zoom_14_golfCourse() {
     assertFeatures(14,
@@ -629,7 +685,7 @@ void zoom_8_forest_largeArea() {
   @Test
   void zoom_12_tallBuilding_100mHeight() {
     assertFeatures(12,
-      List.of(Map.of("kind", "office", "min_zoom", 12, "name", "Skyscraper", "elevation", "100")),
+      List.of(Map.of("kind", "office", "min_zoom", 12, "name", "Skyscraper", "elevation", 100)),
       process(SimpleFeature.create(
         AREA_12K_SQ_M,
         new HashMap<>(Map.of(