Merge pull request #622 from mapbox/cluster-maxzoom

Take cluster distance into account when guessing a maxzoom

CHANGELOG.md

@@ -1,3 +1,7 @@
+## 1.30.5
+
+* Take cluster distance into account when guessing a maxzoom
+
 ## 1.30.4
 
 * Features within the z0 tile buffer of the antimeridian (not only

main.cpp

@@ -1985,6 +1985,20 @@ int read_input(std::vector<source> &sources, char *fname, int maxzoom, int minzo
 			if (!quiet) {
 				fprintf(stderr, "Choosing a maxzoom of -z%d for features about %d feet (%d meters) apart\n", maxzoom, (int) ceil(dist_ft), (int) ceil(dist_ft / 3.28084));
 			}
+
+			bool changed = false;
+			while (maxzoom < 32 - full_detail && maxzoom < 33 - low_detail && cluster_distance > 0) {
+				unsigned long long zoom_mingap = ((1LL << (32 - maxzoom)) / 256 * cluster_distance) * ((1LL << (32 - maxzoom)) / 256 * cluster_distance);
+				if (avg > zoom_mingap) {
+					break;
+				}
+
+				maxzoom++;
+				changed = true;
+			}
+			if (changed) {
+				printf("Choosing a maxzoom of -z%d to keep most features distinct with cluster distance %d\n", maxzoom, cluster_distance);
+			}
 		}
 
 		if (dist_count != 0) {

version.hpp

@@ -1,6 +1,6 @@
 #ifndef VERSION_HPP
 #define VERSION_HPP
 
-#define VERSION "v1.30.4"
+#define VERSION "v1.30.5"
 
 #endif