Merge files into one layer if a name is specified with -l

README.md

@@ -54,7 +54,8 @@ Options
 
 ### Naming
 
- * -l _name_: Layer name (default "file" if source is file.json or output is file.mbtiles). Only works if there is only one layer.
+ * -l _name_: Layer name (default "file" if source is file.json or output is file.mbtiles). If there are multiple input files
+   specified, the files are all merged into the single named layer.
  * -n _name_: Human-readable name (default file.json)
 
 ### File control

decode.cc

@@ -109,6 +109,20 @@ void handle(std::string message, int z, unsigned x, unsigned y, int describe) {
 		mapnik::vector::tile_layer layer = tile.layers(l);
 		int extent = layer.extent();
 
+		if (describe) {
+			if (l != 0) {
+				printf(",\n");
+			}
+
+			printf("{ \"type\": \"FeatureCollection\"");
+			printf(", \"properties\": { \"name\": ");
+			printq(layer.name().c_str());
+			printf(" }");
+			printf(", \"features\": [\n");
+
+			within = 0;
+		}
+
 		for (int f = 0; f < layer.features_size(); f++) {
 			mapnik::vector::tile_feature feat = layer.features(f);
 			int px = 0, py = 0;
@@ -275,6 +289,7 @@ void handle(std::string message, int z, unsigned x, unsigned y, int describe) {
 
 				int state = 0;
 				for (unsigned i = 0; i < rings.size(); i++) {
+					printf("AREA %f   ", areas[i]);
 					if (areas[i] <= 0) {
 						if (state != 0) {
 							// new multipolygon
@@ -316,6 +331,10 @@ void handle(std::string message, int z, unsigned x, unsigned y, int describe) {
 
 			printf(" } }\n");
 		}
+
+		if (describe) {
+			printf("] }\n");
+		}
 	}
 
 	printf("] }\n");

geojson.c

@@ -796,31 +796,48 @@ int read_json(int argc, char **argv, char *fname, const char *layername, int max
 	unsigned midx = 0, midy = 0;
 	long long seq = 0;
 
-	int nlayers = argc;
+	int nlayers;
-	if (nlayers == 0) {
+	if (layername != NULL) {
 		nlayers = 1;
+	} else {
+		nlayers = argc;
+		if (nlayers == 0) {
+			nlayers = 1;
+		}
 	}
 
-	int layer;
+	int nsources = argc;
-	for (layer = 0; layer < nlayers; layer++) {
+	if (nsources == 0) {
+		nsources = 1;
+	}
+
+	int source;
+	for (source = 0; source < nsources; source++) {
 		json_pull *jp;
 		const char *reading;
 		FILE *fp;
 
-		if (layer >= argc) {
+		if (source >= argc) {
 			reading = "standard input";
 			fp = stdin;
 		} else {
-			reading = argv[layer];
+			reading = argv[source];
-			fp = fopen(argv[layer], "r");
+			fp = fopen(argv[source], "r");
 			if (fp == NULL) {
-				perror(argv[layer]);
+				perror(argv[source]);
 				continue;
 			}
 		}
 
 		jp = json_begin_file(fp);
 
+		int layer;
+		if (nlayers == 1) {
+			layer = 0;
+		} else {
+			layer = source;
+		}
+
 		parse_json(jp, reading, &seq, &metapos, &geompos, &indexpos, exclude, include, exclude_all, metafile, geomfile, indexfile, poolfile, treefile, fname, maxzoom, layer, droprate, file_bbox);
 
 		json_end(jp);
@@ -867,7 +884,7 @@ int read_json(int argc, char **argv, char *fname, const char *layername, int max
 
 	char *layernames[nlayers];
 	for (i = 0; i < nlayers; i++) {
-		if (argc <= 1 && layername != NULL) {
+		if (layername != NULL) {
 			layernames[i] = strdup(layername);
 		} else {
 			char *src = argv[i];
@@ -892,7 +909,6 @@ int read_json(int argc, char **argv, char *fname, const char *layername, int max
 			if (cp != NULL) {
 				*cp = '\0';
 			}
-			layername = trunc;
 
 			char *out = trunc;
 			for (cp = trunc; *cp; cp++) {
@@ -1137,7 +1153,7 @@ int read_json(int argc, char **argv, char *fname, const char *layername, int max
 		midlon = maxlon;
 	}
 
-	mbtiles_write_metadata(outdb, fname, layernames, minzoom, maxzoom, minlat, minlon, maxlat, maxlon, midlat, midlon, file_keys, nlayers);  // XXX layers
+	mbtiles_write_metadata(outdb, fname, layernames, minzoom, maxzoom, minlat, minlon, maxlat, maxlon, midlat, midlon, file_keys, nlayers);
 
 	for (i = 0; i < nlayers; i++) {
 		pool_free_strings(&file_keys1[i]);

man/tippecanoe.1

@@ -54,7 +54,8 @@ it encounters.
 .SS Naming
 .RS
 .IP \(bu 2
-\-l \fIname\fP: Layer name (default "file" if source is file.json or output is file.mbtiles). Only works if there is only one layer.
+\-l \fIname\fP: Layer name (default "file" if source is file.json or output is file.mbtiles). If there are multiple input files
+specified, the files are all merged into the single named layer.
 .IP \(bu 2
 \-n \fIname\fP: Human\-readable name (default file.json)
 .RE