Clean up polygon geometry again after coalescing

CHANGELOG.md

@@ -1,3 +1,7 @@
+## 1.9.14
+
+* Clean up polygons after coalescing, if necessary
+
 ## 1.9.13
 
 * Don't trust the OS so much about how many files can be open

README.md

@@ -111,7 +111,9 @@ resolution is obtained than by using a smaller _maxzoom_ or _detail_.
 
 ### Doing more
 
- * -ac or --coalesce: Coalesce adjacent line and polygon features that have the same properties
+ * -ac or --coalesce: Coalesce adjacent line and polygon features that have the same properties.
+   Note that when overlapping polygons are coalesced, the overlapping region is treated as a hole,
+   which may not be what you want.
  * -ar or --reverse: Try reversing the directions of lines to make them coalesce and compress better
  * -ao or --reorder: Reorder features to put ones with the same properties in sequence, to try to get them to coalesce
  * -al or --drop-lines: Let "dot" dropping at lower zooms apply to lines too

man/tippecanoe.1

@@ -134,7 +134,9 @@ compensate for the larger marker, or \-rf\fInumber\fP to allow at most \fInumber
 .SS Doing more
 .RS
 .IP \(bu 2
-\-ac or \-\-coalesce: Coalesce adjacent line and polygon features that have the same properties
+\-ac or \-\-coalesce: Coalesce adjacent line and polygon features that have the same properties.
+Note that when overlapping polygons are coalesced, the overlapping region is treated as a hole,
+which may not be what you want.
 .IP \(bu 2
 \-ar or \-\-reverse: Try reversing the directions of lines to make them coalesce and compress better
 .IP \(bu 2

tests/overlap/in.json

@@ -0,0 +1 @@
+{"type":"FeatureCollection","features":[{"type":"Feature","properties":{},"geometry":{"type":"Polygon","coordinates":[[[-81.5625,63.39152174400882],[-113.90625,53.12040528310657],[-135.703125,29.22889003019423],[-118.125,-9.79567758282973],[-75.9375,-31.353636941500987],[-17.578125,-22.593726063929296],[-5.625,8.407168163601076],[-10.1953125,50.51342652633956],[-28.125,59.712097173322924],[-81.5625,63.39152174400882]]]}},{"type":"Feature","properties":{},"geometry":{"type":"Polygon","coordinates":[[[-93.515625,75.32002523220804],[-113.90625,69.41124235697256],[-117.0703125,60.06484046010452],[-103.35937499999999,39.36827914916011],[-71.3671875,29.84064389983444],[-37.265625,34.88593094075317],[-3.515625,61.270232790000634],[-33.3984375,79.03843742487174],[-74.8828125,79.17133464081945],[-93.515625,75.32002523220804]]]}}]}

tests/overlap/out/-z0.json

@@ -0,0 +1,20 @@
+{ "type": "FeatureCollection", "properties": {
+"bounds": "-135.703125,-31.353637,-3.515625,79.171335",
+"center": "-3.515625,0.000000,0",
+"description": "tests/overlap/out/-z0.json.check.mbtiles",
+"format": "pbf",
+"json": "{\"vector_layers\": [ { \"id\": \"in\", \"description\": \"\", \"minzoom\": 0, \"maxzoom\": 0, \"fields\": {} } ] }",
+"maxzoom": "0",
+"minzoom": "0",
+"name": "tests/overlap/out/-z0.json.check.mbtiles",
+"type": "overlay",
+"version": "2"
+}, "features": [
+{ "type": "FeatureCollection", "properties": { "zoom": 0, "x": 0, "y": 0 }, "features": [
+{ "type": "FeatureCollection", "properties": { "layer": "in" }, "features": [
+{ "type": "Feature", "properties": {  }, "geometry": { "type": "Polygon", "coordinates": [ [ [ -33.398438, 79.038437 ], [ -3.515625, 61.312452 ], [ -37.265625, 34.957995 ], [ -71.367188, 29.916852 ], [ -103.359375, 39.368279 ], [ -117.070312, 60.108670 ], [ -113.906250, 69.442128 ], [ -93.515625, 75.342282 ], [ -74.882812, 79.171335 ], [ -33.398438, 79.038437 ] ] ] } }
+,
+{ "type": "Feature", "properties": {  }, "geometry": { "type": "Polygon", "coordinates": [ [ [ -28.125000, 59.756395 ], [ -10.195312, 50.513427 ], [ -5.625000, 8.407168 ], [ -17.578125, -22.593726 ], [ -75.937500, -31.353637 ], [ -118.125000, -9.795678 ], [ -135.703125, 29.228890 ], [ -113.906250, 53.173119 ], [ -81.562500, 63.391522 ], [ -28.125000, 59.756395 ] ] ] } }
+] }
+] }
+] }

tests/overlap/out/-z0_--coalesce.json

@@ -0,0 +1,18 @@
+{ "type": "FeatureCollection", "properties": {
+"bounds": "-135.703125,-31.353637,-3.515625,79.171335",
+"center": "-3.515625,0.000000,0",
+"description": "tests/overlap/out/-z0_--coalesce.json.check.mbtiles",
+"format": "pbf",
+"json": "{\"vector_layers\": [ { \"id\": \"in\", \"description\": \"\", \"minzoom\": 0, \"maxzoom\": 0, \"fields\": {} } ] }",
+"maxzoom": "0",
+"minzoom": "0",
+"name": "tests/overlap/out/-z0_--coalesce.json.check.mbtiles",
+"type": "overlay",
+"version": "2"
+}, "features": [
+{ "type": "FeatureCollection", "properties": { "zoom": 0, "x": 0, "y": 0 }, "features": [
+{ "type": "FeatureCollection", "properties": { "layer": "in" }, "features": [
+{ "type": "Feature", "properties": {  }, "geometry": { "type": "Polygon", "coordinates": [ [ [ -33.398438, 79.038437 ], [ -3.515625, 61.312452 ], [ -15.556641, 53.488046 ], [ -10.195312, 50.513427 ], [ -5.625000, 8.407168 ], [ -17.578125, -22.593726 ], [ -75.937500, -31.353637 ], [ -118.125000, -9.795678 ], [ -135.703125, 29.228890 ], [ -113.906250, 53.173119 ], [ -112.236328, 53.800651 ], [ -117.070312, 60.108670 ], [ -113.906250, 69.442128 ], [ -93.515625, 75.342282 ], [ -74.882812, 79.171335 ], [ -33.398438, 79.038437 ] ], [ [ -112.236328, 53.800651 ], [ -103.359375, 39.368279 ], [ -71.367188, 29.916852 ], [ -37.265625, 34.957995 ], [ -15.556641, 53.488046 ], [ -28.125000, 59.756395 ], [ -81.562500, 63.391522 ], [ -112.236328, 53.800651 ] ] ] } }
+] }
+] }
+] }

tile.cc

@@ -538,7 +538,6 @@ void *partial_feature_worker(void *v) {
 			// Give Clipper a chance to try to fix it.
 			for (size_t i = 0; i < geoms.size(); i++) {
 				geoms[i] = clean_or_clip_poly(geoms[i], 0, 0, 0, false);
-				geoms[i] = close_poly(geoms[i]);
 			}
 		}
 
@@ -950,6 +949,14 @@ long long write_tile(FILE *geoms, long long *geompos_in, char *metabase, char *s
 					features[j][x].geom = simplify_lines(features[j][x].geom, 32, 0);
 				}
 
+				if (features[j][x].type == VT_POLYGON) {
+					if (features[j][x].coalesced) {
+						features[j][x].geom = clean_or_clip_poly(features[j][x].geom, 0, 0, 0, false);
+					}
+
+					features[j][x].geom = close_poly(features[j][x].geom);
+				}
+
 				if (features[j][x].geom.size() > 0) {
 					out.push_back(features[j][x]);
 				}

version.h

@@ -1 +1 @@
-#define VERSION "tippecanoe v1.9.13\n"
+#define VERSION "tippecanoe v1.9.14\n"