diegoripley/tippecanoe
1
0
Fork 0
mirror of https://github.com/felt/tippecanoe.git synced 2026-10-02 08:25:40 +02:00
Code Issues Packages Projects Releases Wiki Activity

Add an option to merge adjacent polygons together to reduce tile size

Browse Source
This commit is contained in:
Eric Fischer
2016-10-24 17:22:07 -07:00
parent f32916c472
commit 2798bf7b6f
5 changed files with 41 additions and 8 deletions
Download Patch File Download Diff File Expand all files Collapse all files
tile.cpp
+36 -8
View File
@@ -647,7 +647,9 @@ bool edges_same(std::pair<std::vector<edge>::iterator, std::vector<edge>::iterat
return true;
}
void find_common_edges(std::vector<partial> &partials, int z, int line_detail, double simplification, int maxzoom) {
bool find_common_edges(std::vector<partial> &partials, int z, int line_detail, double simplification, int maxzoom, double merge_fraction) {
size_t merge_count = ceil((1 - merge_fraction) * partials.size());
for (size_t i = 0; i < partials.size(); i++) {
if (partials[i].t == VT_POLYGON) {
for (size_t j = 0; j < partials[i].geoms.size(); j++) {
@@ -928,9 +930,17 @@ void find_common_edges(std::vector<partial> &partials, int z, int line_detail, d
// If necessary, merge some adjacent polygons into some other polygons
#if 0
size_t merged = 0;
std::map<unsigned long long, size_t> merge_order;
for (size_t i = 0; i < partials.size(); i++) {
for (size_t j = 0; j < partials[i].arc_polygon.size(); j++) {
merge_order.insert(std::pair<unsigned long long, size_t>(partials[i].index - partials[i].index2, i));
}
for (auto mo = merge_order.begin(); mo != merge_order.end(); ++mo) {
if (merged >= merge_count) {
break;
}
size_t i = mo->second;
for (size_t j = 0; j < partials[i].arc_polygon.size() && merged < merge_count; j++) {
if (merge_candidates.count(-partials[i].arc_polygon[j]) > 0) {
auto r = merge_candidates.equal_range(-partials[i].arc_polygon[j]);
for (auto a = r.first; a != r.second; ++a) {
@@ -1011,6 +1021,7 @@ void find_common_edges(std::vector<partial> &partials, int z, int line_detail, d
}
partials[a->second].arc_polygon.clear();
merged++;
for (size_t k = 0; k < additions.size(); k++) {
partials[i].arc_polygon.push_back(additions[k]);
@@ -1038,7 +1049,6 @@ void find_common_edges(std::vector<partial> &partials, int z, int line_detail, d
}
}
}
#endif
// Turn the arc representations of the polygons back into standard polygon geometries
@@ -1082,11 +1092,18 @@ void find_common_edges(std::vector<partial> &partials, int z, int line_detail, d
}
}
}
if (merged >= merge_count) {
return true;
} else {
return false;
}
}
long long write_tile(FILE *geoms, long long *geompos_in, char *metabase, char *stringpool, int z, unsigned tx, unsigned ty, int detail, int min_detail, int basezoom, sqlite3 *outdb, double droprate, int buffer, const char *fname, FILE **geomfile, int minzoom, int maxzoom, double todo, volatile long long *along, long long alongminus, double gamma, int child_shards, long long *meta_off, long long *pool_off, unsigned *initial_x, unsigned *initial_y, volatile int *running, double simplification, std::vector<std::map<std::string, layermap_entry>> *layermaps, std::vector<std::vector<std::string>> *layer_unmaps) {
int line_detail;
double fraction = 1;
double merge_fraction = 1;
long long og = *geompos_in;
@@ -1126,7 +1143,7 @@ long long write_tile(FILE *geoms, long long *geompos_in, char *metabase, char *s
double fraction_accum = 0;
unsigned long long previndex = 0, density_previndex = 0;
unsigned long long previndex = 0, density_previndex = 0, merge_previndex = 0;
double scale = (double) (1LL << (64 - 2 * (z + 8)));
double gap = 0, density_gap = 0;
double spacing = 0;
@@ -1320,7 +1337,7 @@ long long write_tile(FILE *geoms, long long *geompos_in, char *metabase, char *s
}
unsigned long long index = 0;
if (additional[A_CALCULATE_FEATURE_DENSITY] || gamma > 0) {
if (additional[A_CALCULATE_FEATURE_DENSITY] || gamma > 0 || additional[A_MERGE_POLYGONS_AS_NEEDED]) {
index = encode(bbox[0] / 2 + bbox[2] / 2, bbox[1] / 2 + bbox[3] / 2);
}
@@ -1372,14 +1389,19 @@ long long write_tile(FILE *geoms, long long *geompos_in, char *metabase, char *s
p.simplification = simplification;
p.id = id;
p.has_id = has_id;
p.index2 = merge_previndex;
p.index = index;
partials.push_back(p);
}
merge_previndex = index;
}
first_time = false;
bool merge_successful = true;
if (additional[A_DETECT_SHARED_BORDERS]) {
find_common_edges(partials, z, line_detail, simplification, maxzoom);
if (additional[A_DETECT_SHARED_BORDERS] || (additional[A_MERGE_POLYGONS_AS_NEEDED] && merge_fraction < 1)) {
merge_successful = find_common_edges(partials, z, line_detail, simplification, maxzoom, merge_fraction);
}
int tasks = ceil((double) CPUS / *running);
@@ -1651,6 +1673,12 @@ long long write_tile(FILE *geoms, long long *geompos_in, char *metabase, char *s
fprintf(stderr, "Going to try gamma of %0.3f to make it fit\n", gamma);
}
line_detail++; // to keep it the same when the loop decrements it
} else if (additional[A_MERGE_POLYGONS_AS_NEEDED] && merge_fraction > .05 && merge_successful) {
merge_fraction = merge_fraction * max_tile_size / compressed.size() * 0.95;
if (!quiet) {
fprintf(stderr, "Going to try merging %0.2f%% of the polygons to make it fit\n", 100 - merge_fraction * 100);
}
line_detail++; // to keep it the same when the loop decrements it
}
} else {
if (pthread_mutex_lock(&db_lock) != 0) {