Adjust midzoom places display (#576)

* Add failing unit tests exposing Places prioritization bug at zoom 7
* Fix Places prioritization by passing pm:population to zoomsIndex

When the Places.java code was refactored to support Overture data, the zoom
calculation logic was split into separate indexes (osmKindsIndex and zoomsIndex).
However, the computed pm:population value from osmKindsIndex was not being passed
to zoomsIndex, causing population-based zoom rules to fail.

This caused places without population tags (like place=locality) to incorrectly
appear at zoom 7 instead of zoom 12+, while more important places (like cities)
were correctly prioritized.

* Fix Overture Places zoom levels by using pm:populationFallback

Make Overture data processing always set pm:populationFallback marker
to trigger fallback zoom rules. This ensures Overture places get the
higher minzoom values (city=8, town=9) without adding source-specific
logic to zoom rules.

🤖 Assisted by [Claude Code](https://claude.com/claude-code)

Author: migurski

CHANGELOG.md

@@ -1,3 +1,7 @@
+Tiles 4.14.3
+------
+- Fix OSM place selection regression at zoom=7 [#576]
+
 Tiles 4.14.2
 ------
 - Upgrade to planetiler 0.10.1 with workaround for JTS polygon negative buffer bug [#538]

tiles/src/main/java/com/protomaps/basemap/Basemap.java

@@ -133,7 +133,7 @@ public String description() {
 
   @Override
   public String version() {
-    return "4.14.2";
+    return "4.14.3";
   }
 
   @Override

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

@@ -75,8 +75,8 @@ public Places(CountryCoder countryCoder) {
     rule(with("place", "state", "province"), with("pm:country", "US", "CA", "BR", "IN", "CN", "AU"),
       use("pm:kind", "region")),
     rule(with("place", "city", "town"), use("pm:kind", "locality"), use("pm:kindDetail", fromTag("place"))),
-    rule(with("place", "city"), without("population"), use("pm:population", 5000)),
-    rule(with("place", "town"), without("population"), use("pm:population", 10000)),
+    rule(with("place", "city"), without("population"), use("pm:populationFallback", 5000)),
+    rule(with("place", "town"), without("population"), use("pm:populationFallback", 10000)),
 
     // Neighborhood-scale places
 
@@ -87,17 +87,17 @@ public Places(CountryCoder countryCoder) {
     // Smaller places detailed in OSM but not fully tested for Overture
 
     rule(with("place", "village"), use("pm:kind", "locality"), use("pm:kindDetail", fromTag("place"))),
-    rule(with("place", "village"), without("population"), use("pm:population", 2000)),
+    rule(with("place", "village"), without("population"), use("pm:populationFallback", 2000)),
     rule(with("place", "locality"), use("pm:kind", "locality")),
-    rule(with("place", "locality"), without("population"), use("pm:population", 1000)),
+    rule(with("place", "locality"), without("population"), use("pm:populationFallback", 1000)),
     rule(with("place", "hamlet"), use("pm:kind", "locality")),
-    rule(with("place", "hamlet"), without("population"), use("pm:population", 200)),
+    rule(with("place", "hamlet"), without("population"), use("pm:populationFallback", 200)),
     rule(with("place", "isolated_dwelling"), use("pm:kind", "locality")),
-    rule(with("place", "isolated_dwelling"), without("population"), use("pm:population", 100)),
+    rule(with("place", "isolated_dwelling"), without("population"), use("pm:populationFallback", 100)),
     rule(with("place", "farm"), use("pm:kind", "locality")),
-    rule(with("place", "farm"), without("population"), use("pm:population", 50)),
+    rule(with("place", "farm"), without("population"), use("pm:populationFallback", 50)),
     rule(with("place", "allotments"), use("pm:kind", "locality")),
-    rule(with("place", "allotments"), without("population"), use("pm:population", 1000))
+    rule(with("place", "allotments"), without("population"), use("pm:populationFallback", 1000))
 
   )).index();
 
@@ -126,10 +126,14 @@ public Places(CountryCoder countryCoder) {
     rule(with("pm:kind", "region"), use("pm:minzoom", 8), use("pm:maxzoom", 11)),
     rule(with("pm:kind", "region"), with("pm:country", "US", "CA", "BR", "IN", "CN", "AU"), use("pm:kindRank", 1)),
 
-    rule(with("pm:kind", "locality"), use("pm:kindRank", 4), use("pm:minzoom", 7), use("pm:maxzoom", 15)),
-    rule(with("pm:kind", "locality"), atLeast("pm:population", 1000), use("pm:minzoom", 12)),
-    rule(with("pm:kind", "locality"), with("pm:kindDetail", "city"), use("pm:kindRank", 2), use("pm:minzoom", 8)),
-    rule(with("pm:kind", "locality"), with("pm:kindDetail", "town"), use("pm:kindRank", 2), use("pm:minzoom", 9)),
+    rule(with("pm:kind", "locality"), use("pm:kindRank", 4), use("pm:minzoom", 11), use("pm:maxzoom", 15)),
+    rule(with("pm:kind", "locality"), with("pm:populationFallback"), use("pm:minzoom", 12)),
+    rule(with("pm:kind", "locality"), with("pm:kindDetail", "city"), use("pm:kindRank", 2), use("pm:minzoom", 7)),
+    rule(with("pm:kind", "locality"), with("pm:kindDetail", "city"), with("pm:populationFallback"),
+      use("pm:minzoom", 8)),
+    rule(with("pm:kind", "locality"), with("pm:kindDetail", "town"), use("pm:kindRank", 2), use("pm:minzoom", 7)),
+    rule(with("pm:kind", "locality"), with("pm:kindDetail", "town"), with("pm:populationFallback"),
+      use("pm:minzoom", 9)),
     rule(with("pm:kind", "locality"), with("pm:kindDetail", "village"), use("pm:kindRank", 3), use("pm:minzoom", 10)),
     rule(with("pm:kind", "locality"), with("pm:kindDetail", "village"), atLeast("pm:population", 2000),
       use("pm:minzoom", 11)),
@@ -226,6 +230,20 @@ static int getSortKey(double minZoom, int kindRank, long population, String name
       15, 3
     ), 0);
 
+  private Map<String, Object> makeTagMap(String kind, String kindDetail, Integer population,
+    Integer populationFallback) {
+    Map<String, Object> computedTags = new HashMap<>();
+
+    computedTags.put("pm:kind", kind);
+    computedTags.put("pm:kindDetail", kindDetail);
+    computedTags.put("pm:population", population);
+    if (populationFallback > 0) {
+      computedTags.put("pm:populationFallback", populationFallback);
+    }
+
+    return computedTags;
+  }
+
   public void processOsm(SourceFeature sf, FeatureCollector features) {
     if (!sf.isPoint() || !sf.hasTag("name") || !sf.hasTag("place")) {
       return;
@@ -245,6 +263,7 @@ public void processOsm(SourceFeature sf, FeatureCollector features) {
     String kind = getString(sf, matches, "pm:kind", "pm:undefined");
     String kindDetail = getString(sf, matches, "pm:kindDetail", "");
     Integer population = getInteger(sf, matches, "pm:population", 0);
+    Integer populationFallback = getInteger(sf, matches, "pm:populationFallback", 0);
 
     if ("pm:undefined".equals(kind)) {
       return;
@@ -254,9 +273,15 @@ public void processOsm(SourceFeature sf, FeatureCollector features) {
     Integer maxZoom;
     Integer kindRank;
 
-    var sf2 = new Matcher.SourceFeatureWithComputedTags(sf, Map.of("pm:kind", kind, "pm:kindDetail", kindDetail));
+    var computedTags = makeTagMap(kind, kindDetail, population, populationFallback);
+    var sf2 = new Matcher.SourceFeatureWithComputedTags(sf, computedTags);
     var zoomMatches = zoomsIndex.getMatches(sf2);
 
+    // Use populationFallback for sorting if no real population
+    if (population == 0 && populationFallback > 0) {
+      population = populationFallback;
+    }
+
     minZoom = getInteger(sf2, zoomMatches, "pm:minzoom", 99);
     maxZoom = getInteger(sf2, zoomMatches, "pm:maxzoom", 99);
     kindRank = getInteger(sf2, zoomMatches, "pm:kindRank", 99);
@@ -345,11 +370,25 @@ public void processOverture(SourceFeature sf, FeatureCollector features) {
       return;
     }
 
+    // Extract population (if available)
+    Integer population = 0;
+    if (sf.hasTag("population")) {
+      Object popValue = sf.getTag("population");
+      if (popValue instanceof Number number) {
+        population = number.intValue();
+      }
+    }
+
+    // Overture always uses populationFallback for zoom calculations to get consistent behavior
+    // This ensures Overture places get the higher minzoom levels (8 for city, 9 for town, etc)
+    Integer populationFallback = 1; // Marker value to trigger fallback zoom levels
+
     Integer minZoom;
     Integer maxZoom;
     Integer kindRank;
 
-    var sf2 = new Matcher.SourceFeatureWithComputedTags(sf, Map.of("pm:kind", kind, "pm:kindDetail", kindDetail));
+    var computedTags = makeTagMap(kind, kindDetail, population, populationFallback);
+    var sf2 = new Matcher.SourceFeatureWithComputedTags(sf, computedTags);
     var zoomMatches = zoomsIndex.getMatches(sf2);
 
     minZoom = getInteger(sf2, zoomMatches, "pm:minzoom", 99);
@@ -359,15 +398,6 @@ public void processOverture(SourceFeature sf, FeatureCollector features) {
     // Extract name
     String name = sf.getString("names.primary");
 
-    // Extract population (if available)
-    Integer population = 0;
-    if (sf.hasTag("population")) {
-      Object popValue = sf.getTag("population");
-      if (popValue instanceof Number number) {
-        population = number.intValue();
-      }
-    }
-
     int populationRank = 0;
 
     for (int i = 0; i < popBreaks.length; i++) {

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

@@ -202,6 +202,89 @@ void testAllotmentsOsm() {
         0
       )));
   }
+
+  @Test
+  void testLocalityNoPopulationHasCorrectMinZoom() {
+    // Place Mahiouindo - OSM node/4535788658
+    // place=locality without population should have _minzoom=12 (not 7)
+    assertFeatures(7,
+      List.of(Map.of("_minzoom", 12, "_maxzoom", 14, "kind", "locality", "kind_detail", "locality")),
+      process(SimpleFeature.create(
+        newPoint(2.5892, 7.3321),
+        new HashMap<>(Map.of("place", "locality", "name", "Place Mahiouindo")),
+        "osm",
+        null,
+        0
+      )));
+  }
+
+  @Test
+  void testLocalityNoPopulationMinZoom() {
+    // Place Mahiouindo - should have min_zoom=13 (minzoom=12 + 1)
+    assertFeatures(12,
+      List.of(Map.of("kind", "locality",
+        "kind_detail", "locality",
+        "min_zoom", 13,
+        "population", 1000)),
+      process(SimpleFeature.create(
+        newPoint(2.5892, 7.3321),
+        new HashMap<>(Map.of("place", "locality", "name", "Place Mahiouindo")),
+        "osm",
+        null,
+        0
+      )));
+  }
+
+  @Test
+  void testCityWithPopulationVisibleAtZoom7() {
+    // Kétou - OSM node/2313302870
+    // place=city with population=160000 should be visible at zoom 7 (minzoom=7, min_zoom=8)
+    assertFeatures(7,
+      List.of(Map.of("kind", "locality",
+        "kind_detail", "city",
+        "min_zoom", 8,
+        "population", 160000)),
+      process(SimpleFeature.create(
+        newPoint(2.5892, 7.3632),
+        new HashMap<>(Map.of("place", "city", "name", "Kétou", "population", "160000")),
+        "osm",
+        null,
+        0
+      )));
+  }
+
+  @Test
+  void testCityWithoutPopulationHasCorrectMinZoom() {
+    // Cities without population tags get populationFallback=5000 and should have _minZoom=8
+    assertFeatures(8,
+      List.of(Map.of("_minzoom", 8, "kind", "locality", "kind_detail", "city", "population", 5000)),
+      process(SimpleFeature.create(
+        newPoint(2.5892, 7.3632),
+        new HashMap<>(Map.of("place", "city", "name", "Some City")),
+        "osm",
+        null,
+        0
+      )));
+  }
+
+  @Test
+  void testOuidahWithWikidataVisibleAtZoom6() {
+    // Ouidah - OSM node/313015821, wikidata Q850031
+    // Has wikidata entry in places.csv: Q850031,6,-1,8
+    // Should be visible at zoom 6 (wikidata override)
+    assertFeatures(6,
+      List.of(Map.of("kind", "locality",
+        "kind_detail", "city",
+        "population", 160000)),
+      process(SimpleFeature.create(
+        newPoint(2.0854, 6.3616),
+        new HashMap<>(Map.of("place", "city", "name", "Ouidah", "population", "160000", "wikidata", "Q850031")),
+        "osm",
+        null,
+        0
+      )));
+  }
+
 }