diff --git a/geometry.cpp b/geometry.cpp
index 66cb5651..89cfed7a 100644
--- a/geometry.cpp
+++ b/geometry.cpp
@@ -578,8 +578,8 @@ drawvec reorder_lines(const drawvec &geom) {
 	// instead of down and to the right
 	// so that it will coalesce better
 
-	unsigned long long l1 = encode_index(coordinate_to_encodable(geom[0].x), coordinate_to_encodable(geom[0].y));
-	unsigned long long l2 = encode_index(coordinate_to_encodable(geom[geom.size() - 1].x), coordinate_to_encodable(geom[geom.size() - 1].y));
+	index_t l1 = encode_index(coordinate_to_encodable(geom[0].x), coordinate_to_encodable(geom[0].y));
+	index_t l2 = encode_index(coordinate_to_encodable(geom[geom.size() - 1].x), coordinate_to_encodable(geom[geom.size() - 1].y));
 
 	if (l1 > l2) {
 		drawvec out;
diff --git a/main.cpp b/main.cpp
index bf31232b..1c4c059b 100644
--- a/main.cpp
+++ b/main.cpp
@@ -283,13 +283,13 @@ static void insert(struct mergelist *m, struct mergelist **head, unsigned char *
 
 struct drop_state {
 	double gap;
-	unsigned long long previndex;
+	index_t previndex;
 	double interval;
 	double seq;  // floating point because interval is
 };
 
 struct drop_densest {
-	unsigned long long gap;
+	index_t gap;
 	size_t seq;
 
 	bool operator<(const drop_densest &o) const {
@@ -822,7 +822,7 @@ void radix1(int *geomfds_in, int *indexfds_in, int inputs, int prefix, int split
 
 			for (size_t a = 0; a < indexst.st_size / sizeof(struct index); a++) {
 				struct index ix = indexmap[a];
-				unsigned long long which = (ix.ix << prefix) >> (64 - splitbits);
+				index_t which = (ix.ix << prefix) >> (2 * GLOBAL_DETAIL - splitbits);
 				long long pos = sub_geompos[which];
 
 				fwrite_check(geommap + ix.start, ix.end - ix.start, 1, geomfiles[which], &sub_geompos[which], "geom");
@@ -2375,7 +2375,7 @@ std::pair<int, metadata> read_input(std::vector<source> &sources, char *fname, i
 
 			bool changed = false;
 			while (maxzoom < GLOBAL_DETAIL - full_detail && maxzoom < GLOBAL_DETAIL + 1 - low_detail && maxzoom < cluster_maxzoom && cluster_distance > 0) {
-				unsigned long long zoom_mingap = ((1LL << (GLOBAL_DETAIL - maxzoom)) / 256 * cluster_distance) * ((1LL << (GLOBAL_DETAIL - maxzoom)) / 256 * cluster_distance);
+				index_t zoom_mingap = ((1LL << (GLOBAL_DETAIL - maxzoom)) / 256 * cluster_distance) * ((1LL << (GLOBAL_DETAIL - maxzoom)) / 256 * cluster_distance);
 				if (avg > zoom_mingap) {
 					break;
 				}
@@ -2487,7 +2487,7 @@ std::pair<int, metadata> read_input(std::vector<source> &sources, char *fname, i
 			long long count;
 			long long fullcount;
 			double gap;
-			unsigned long long previndex;
+			index_t previndex;
 		} tile[MAX_ZOOM + 1], max[MAX_ZOOM + 1];
 
 		{
@@ -2687,7 +2687,7 @@ std::pair<int, metadata> read_input(std::vector<source> &sources, char *fname, i
 
 		if (drop_denser > 0) {
 			std::vector<drop_densest> ddv;
-			unsigned long long previndex = 0;
+			index_t previndex = 0;
 
 			for (long long ip = 0; ip < indices; ip++) {
 				if (map[ip].t == VT_POINT ||
diff --git a/main.hpp b/main.hpp
index 25695e2f..cc578cc2 100644
--- a/main.hpp
+++ b/main.hpp
@@ -13,7 +13,7 @@
 struct index {
 	long long start = 0;
 	long long end = 0;
-	unsigned long long ix = 0;
+	index_t ix = 0;
 	short segment = 0;
 	unsigned short t : 2;
 	unsigned long long seq : (64 - 18);  // pack with segment and t to stay in 32 bytes
diff --git a/projection.cpp b/projection.cpp
index e2262b17..7c973e88 100644
--- a/projection.cpp
+++ b/projection.cpp
@@ -9,8 +9,8 @@
 
 #define UINT_BITS 32
 
-unsigned long long (*encode_index)(unsigned int wx, unsigned int wy) = NULL;
-void (*decode_index)(unsigned long long index, unsigned *wx, unsigned *wy) = NULL;
+index_t (*encode_index)(unsigned int wx, unsigned int wy) = NULL;
+void (*decode_index)(index_t index, unsigned *wx, unsigned *wy) = NULL;
 
 struct projection projections[] = {
 	{"EPSG:4326", lonlat2tile, tile2lonlat, "urn:ogc:def:crs:OGC:1.3:CRS84"},
@@ -154,7 +154,7 @@ unsigned long long encode_hilbert(unsigned int wx, unsigned int wy) {
 	return hilbert_xy2d(1LL << UINT_BITS, wx, wy);
 }
 
-void decode_hilbert(unsigned long long index, unsigned *wx, unsigned *wy) {
+void decode_hilbert(index_t index, unsigned *wx, unsigned *wy) {
 	hilbert_d2xy(1LL << UINT_BITS, index, wx, wy);
 }
 
@@ -176,7 +176,7 @@ unsigned long long encode_quadkey(unsigned int wx, unsigned int wy) {
 static std::atomic<unsigned char> decodex[256];
 static std::atomic<unsigned char> decodey[256];
 
-void decode_quadkey(unsigned long long index, unsigned *wx, unsigned *wy) {
+void decode_quadkey(index_t index, unsigned *wx, unsigned *wy) {
 	static std::atomic<int> initialized(0);
 	if (!initialized) {
 		for (size_t ix = 0; ix < 256; ix++) {
diff --git a/projection.hpp b/projection.hpp
index 789849ec..47983162 100644
--- a/projection.hpp
+++ b/projection.hpp
@@ -2,6 +2,7 @@
 #define PROJECTION_HPP
 
 #define GLOBAL_DETAIL 32
+typedef unsigned long long index_t;
 
 void lonlat2tile(double lon, double lat, int zoom, long long *x, long long *y);
 void epsg3857totile(double ix, double iy, int zoom, long long *x, long long *y);
@@ -19,14 +20,14 @@ struct projection {
 extern struct projection *projection;
 extern struct projection projections[];
 
-extern unsigned long long (*encode_index)(unsigned int wx, unsigned int wy);
-extern void (*decode_index)(unsigned long long index, unsigned *wx, unsigned *wy);
+extern index_t (*encode_index)(unsigned int wx, unsigned int wy);
+extern void (*decode_index)(index_t index, unsigned *wx, unsigned *wy);
 
 unsigned long long encode_quadkey(unsigned int wx, unsigned int wy);
-void decode_quadkey(unsigned long long index, unsigned *wx, unsigned *wy);
+void decode_quadkey(index_t index, unsigned *wx, unsigned *wy);
 
 unsigned long long encode_hilbert(unsigned int wx, unsigned int wy);
-void decode_hilbert(unsigned long long index, unsigned *wx, unsigned *wy);
+void decode_hilbert(index_t index, unsigned *wx, unsigned *wy);
 
 unsigned coordinate_to_encodable(long long coord);
 long long decoded_to_coordinate(unsigned coord);
diff --git a/serial.cpp b/serial.cpp
index f3d088ec..4ed6ed75 100644
--- a/serial.cpp
+++ b/serial.cpp
@@ -682,7 +682,7 @@ int serialize_feature(struct serialization_state *sst, serial_feature &sf, std::
 		*(sst->area_sum) += extent;
 	}
 
-	unsigned long long bbox_index;
+	index_t bbox_index;
 	long long midx, midy;
 
 	if (sf.t == VT_POINT) {
diff --git a/serial.hpp b/serial.hpp
index 2e8ed3d5..d1231950 100644
--- a/serial.hpp
+++ b/serial.hpp
@@ -67,8 +67,8 @@ struct serial_feature {
 	int tippecanoe_maxzoom = -1;
 
 	drawvec geometry = drawvec();
-	unsigned long long index = 0;
-	unsigned long long label_point = 0;
+	index_t index = 0;
+	index_t label_point = 0;
 	long long extent = 0;
 
 	// These fields are not directly serialized, but are used
diff --git a/shared_borders.cpp b/shared_borders.cpp
index 2a1bd2ee..614baba1 100644
--- a/shared_borders.cpp
+++ b/shared_borders.cpp
@@ -367,7 +367,7 @@ bool find_common_edges(std::vector<serial_feature> &features, int z, int line_de
 
 	struct merge_order {
 		ssize_t edge = 0;
-		unsigned long long gap = 0;
+		index_t gap = 0;
 		size_t p1 = 0;
 		size_t p2 = 0;
 
diff --git a/tile.cpp b/tile.cpp
index 1466d5a7..55b55044 100644
--- a/tile.cpp
+++ b/tile.cpp
@@ -705,7 +705,7 @@ static void *simplification_worker(void *v) {
 // get rid of the --gamma option. It does something with the feature spacing to calculate
 // whether each feature should be kept or is in a dense enough context that it should
 // be dropped
-int manage_gap(unsigned long long index, unsigned long long *previndex, double scale, double gamma, double *gap) {
+int manage_gap(index_t index, index_t *previndex, double scale, double gamma, double *gap) {
 	if (gamma > 0) {
 		if (*gap > 0) {
 			if (index == *previndex) {
@@ -742,7 +742,7 @@ int manage_gap(unsigned long long index, unsigned long long *previndex, double s
 // of features that survived the previous gap-choosing, so it first needs to calculate
 // and sort the gaps between them before deciding which new gap threshold will satisfy
 // the need to keep only the requested fraction of features.
-static unsigned long long choose_mingap(std::vector<unsigned long long> const &indices, double f) {
+static index_t choose_mingap(std::vector<unsigned long long> const &indices, double f) {
 	unsigned long long bot = ULLONG_MAX;
 	unsigned long long top = 0;
 
@@ -885,8 +885,8 @@ struct write_tile_args {
 	std::vector<std::map<std::string, layermap_entry>> *layermaps = NULL;
 	std::vector<std::vector<std::string>> *layer_unmaps = NULL;
 	size_t pass = 0;
-	unsigned long long mingap = 0;
-	unsigned long long mingap_out = 0;
+	index_t mingap = 0;
+	index_t mingap_out = 0;
 	long long minextent = 0;
 	long long minextent_out = 0;
 	unsigned long long mindrop_sequence = 0;
@@ -1488,7 +1488,7 @@ bool drop_feature_unless_it_can_be_added_to_a_multiplier_cluster(layer_features
 	return false;  // did not drop because nothing could be found to accumulate attributes onto
 }
 
-long long write_tile(decompressor *geoms, std::atomic<long long> *geompos_in, char *global_stringpool, int z, const unsigned tx, const unsigned ty, const int detail, int min_detail, sqlite3 *outdb, const char *outdir, int buffer, const char *fname, compressor **geomfile, int minzoom, int maxzoom, double todo, std::atomic<long long> *along, long long alongminus, double gamma, int child_shards, long long *pool_off, long long *initial_x, long long *initial_y, std::atomic<int> *running, double simplification, std::vector<std::map<std::string, layermap_entry>> *layermaps, std::vector<std::vector<std::string>> *layer_unmaps, size_t tiling_seg, size_t pass, unsigned long long mingap, long long minextent, unsigned long long mindrop_sequence, const char *prefilter, const char *postfilter, json_object *filter, write_tile_args *arg, atomic_strategy *strategy, bool compressed_input, node *shared_nodes_map, size_t nodepos, std::vector<std::string> const &unidecode_data) {
+long long write_tile(decompressor *geoms, std::atomic<long long> *geompos_in, char *global_stringpool, int z, const unsigned tx, const unsigned ty, const int detail, int min_detail, sqlite3 *outdb, const char *outdir, int buffer, const char *fname, compressor **geomfile, int minzoom, int maxzoom, double todo, std::atomic<long long> *along, long long alongminus, double gamma, int child_shards, long long *pool_off, long long *initial_x, long long *initial_y, std::atomic<int> *running, double simplification, std::vector<std::map<std::string, layermap_entry>> *layermaps, std::vector<std::vector<std::string>> *layer_unmaps, size_t tiling_seg, size_t pass, index_t mingap, long long minextent, unsigned long long mindrop_sequence, const char *prefilter, const char *postfilter, json_object *filter, write_tile_args *arg, atomic_strategy *strategy, bool compressed_input, node *shared_nodes_map, size_t nodepos, std::vector<std::string> const &unidecode_data) {
 	double merge_fraction = 1;
 	double mingap_fraction = 1;
 	double minextent_fraction = 1;
@@ -1525,8 +1525,8 @@ long long write_tile(decompressor *geoms, std::atomic<long long> *geompos_in, ch
 		long long count = 0;
 		double accum_area = 0;
 
-		unsigned long long previndex = 0, density_previndex = 0, merge_previndex = 0;
-		unsigned long long extent_previndex = 0;
+		index_t previndex = 0, density_previndex = 0, merge_previndex = 0;
+		index_t extent_previndex = 0;
 		double scale = (double) (1LL << (64 - 2 * (z + 8)));
 		double gap = 0, density_gap = 0;
 		double spacing = 0;
@@ -1870,7 +1870,7 @@ long long write_tile(decompressor *geoms, std::atomic<long long> *geompos_in, ch
 				}
 			}
 
-			unsigned long long sfindex = sf.index;
+			index_t sfindex = sf.index;
 
 			if (sf.geometry.size() > 0) {
 				if (lead_features_count > max_tile_size || (lead_features_count + other_multiplier_cluster_features_count > max_tile_features && !prevent[P_FEATURE_LIMIT])) {
@@ -2361,7 +2361,7 @@ long long write_tile(decompressor *geoms, std::atomic<long long> *geompos_in, ch
 					continue;
 				} else if (mingap < ULONG_MAX && (additional[A_DROP_DENSEST_AS_NEEDED] || additional[A_COALESCE_DENSEST_AS_NEEDED] || additional[A_CLUSTER_DENSEST_AS_NEEDED])) {
 					mingap_fraction = mingap_fraction * max_tile_features / totalsize * 0.90;
-					unsigned long long mg = choose_mingap(indices, mingap_fraction);
+					index_t mg = choose_mingap(indices, mingap_fraction);
 					if (mg <= mingap) {
 						mg = (mingap + 1) * 1.5;
 
@@ -2468,7 +2468,7 @@ long long write_tile(decompressor *geoms, std::atomic<long long> *geompos_in, ch
 					line_detail++;	// to keep it the same when the loop decrements it
 				} else if (mingap < ULONG_MAX && (additional[A_DROP_DENSEST_AS_NEEDED] || additional[A_COALESCE_DENSEST_AS_NEEDED] || additional[A_CLUSTER_DENSEST_AS_NEEDED])) {
 					mingap_fraction = mingap_fraction * scaled_max_tile_size / (kept_adjust * compressed.size()) * 0.90;
-					unsigned long long mg = choose_mingap(indices, mingap_fraction);
+					index_t mg = choose_mingap(indices, mingap_fraction);
 					if (mg <= mingap) {
 						double nmg = (mingap + 1) * 1.5;
 
@@ -2831,8 +2831,7 @@ int traverse_zooms(int *geomfd, off_t *geom_size, char *global_stringpool, std::
 		size_t zoom_tile_size = 0;
 		size_t zoom_feature_count = 0;
 
-		// yes, these need to be 32, not GLOBAL_DETAIL, because clusters operate on indices, not coordinates
-		unsigned long long zoom_mingap = ((1LL << (32 - z)) / 256 * cluster_distance) * ((1LL << (32 - z)) / 256 * cluster_distance);
+		index_t zoom_mingap = (index_t) ((1LL << (GLOBAL_DETAIL - z)) / 256 * cluster_distance) * ((1LL << (GLOBAL_DETAIL - z)) / 256 * cluster_distance);
 
 		for (size_t pass = 0;; pass++) {
 			pthread_t pthreads[threads];
diff --git a/tile.hpp b/tile.hpp
index 868f55a4..17ff37ae 100644
--- a/tile.hpp
+++ b/tile.hpp
@@ -57,6 +57,6 @@ struct strategy {
 
 int traverse_zooms(int *geomfd, off_t *geom_size, char *stringpool, std::atomic<unsigned> *midx, std::atomic<unsigned> *midy, int &maxzoom, int minzoom, sqlite3 *outdb, const char *outdir, int buffer, const char *fname, const char *tmpdir, double gamma, int full_detail, int low_detail, int min_detail, long long *pool_off, long long *initial_x, long long *initial_y, double simplification, double maxzoom_simplification, std::vector<std::map<std::string, layermap_entry> > &layermap, const char *prefilter, const char *postfilter, std::unordered_map<std::string, attribute_op> const *attribute_accum, struct json_object *filter, std::vector<strategy> &strategies, int iz, struct node *shared_nodes_map, size_t nodepos, int basezoom, double droprate, std::vector<std::string> const &unidecode_data);
 
-int manage_gap(unsigned long long index, unsigned long long *previndex, double scale, double gamma, double *gap);
+int manage_gap(index_t index, index_t *previndex, double scale, double gamma, double *gap);
 
 #endif
diff --git a/write_json.cpp b/write_json.cpp
index bdf1e852..303ab75c 100644
--- a/write_json.cpp
+++ b/write_json.cpp
@@ -268,7 +268,7 @@ void write_coords(json_writer &state, lonlat const &ll, double scale) {
 	}
 }
 
-void layer_to_geojson(mvt_layer const &layer, unsigned z, unsigned x, unsigned y, bool comma, bool name, bool zoom, bool write_dropped, unsigned long long index, long long sequence, long long extent, bool complain, json_writer &state, double scale) {
+void layer_to_geojson(mvt_layer const &layer, unsigned z, unsigned x, unsigned y, bool comma, bool name, bool zoom, bool write_dropped, index_t index, long long sequence, long long extent, bool complain, json_writer &state, double scale) {
 	for (size_t f = 0; f < layer.features.size(); f++) {
 		mvt_feature const &feat = layer.features[f];
 
diff --git a/write_json.hpp b/write_json.hpp
index 523b027b..a690c93f 100644
--- a/write_json.hpp
+++ b/write_json.hpp
@@ -61,7 +61,7 @@ struct json_writer {
 	void adds(std::string const &s);
 };
 
-void layer_to_geojson(mvt_layer const &layer, unsigned z, unsigned x, unsigned y, bool comma, bool name, bool zoom, bool dropped, unsigned long long index, long long sequence, long long extent, bool complain, json_writer &state, double scale);
+void layer_to_geojson(mvt_layer const &layer, unsigned z, unsigned x, unsigned y, bool comma, bool name, bool zoom, bool dropped, index_t index, long long sequence, long long extent, bool complain, json_writer &state, double scale);
 void fprintq(FILE *f, const char *s);
 
 #endif