diff --git a/Makefile b/Makefile index 9e53d17..537edf0 100644 --- a/Makefile +++ b/Makefile @@ -1,6 +1,6 @@ PREFIX=/usr/local -all: tippecanoe enumerate +all: tippecanoe enumerate decode install: tippecanoe cp tippecanoe $(PREFIX)/bin/tippecanoe @@ -16,6 +16,9 @@ tippecanoe: geojson.o jsonpull.o vector_tile.pb.o tile.o clip.o pool.o mbtiles.o enumerate: enumerate.o gcc $(PG) -O3 -g -Wall -o $@ $^ -lsqlite3 +decode: decode.o vector_tile.pb.o + g++ $(PG) -O3 -g -Wall -o $@ $^ -lm -lz -lprotobuf-lite -lsqlite3 + libjsonpull.a: jsonpull.o ar rc $@ $^ ranlib $@ diff --git a/decode.cc b/decode.cc new file mode 100644 index 0000000..9d39b8f --- /dev/null +++ b/decode.cc @@ -0,0 +1,165 @@ +#include +#include +#include +#include +#include +#include +#include +#include "vector_tile.pb.h" + +// https://github.com/mapbox/mapnik-vector-tile/blob/master/src/vector_tile_compression.hpp +inline bool is_compressed(std::string const& data) { + return data.size() > 2 && (uint8_t)data[0] == 0x78 && (uint8_t)data[1] == 0x9C; +} + +// https://github.com/mapbox/mapnik-vector-tile/blob/master/src/vector_tile_compression.hpp +inline int decompress(std::string const& input, std::string & output) { + z_stream inflate_s; + inflate_s.zalloc = Z_NULL; + inflate_s.zfree = Z_NULL; + inflate_s.opaque = Z_NULL; + inflate_s.avail_in = 0; + inflate_s.next_in = Z_NULL; + inflateInit(&inflate_s); + inflate_s.next_in = (Bytef *)input.data(); + inflate_s.avail_in = input.size(); + size_t length = 0; + do { + output.resize(length + 2 * input.size()); + inflate_s.avail_out = 2 * input.size(); + inflate_s.next_out = (Bytef *)(output.data() + length); + int ret = inflate(&inflate_s, Z_FINISH); + if (ret != Z_STREAM_END && ret != Z_OK && ret != Z_BUF_ERROR) { + return 0; + } + + length += (2 * input.size() - inflate_s.avail_out); + } while (inflate_s.avail_out == 0); + inflateEnd(&inflate_s); + output.resize(length); + return 1; +} + +int dezig(unsigned n) { + return (n >> 1) ^ (-(n & 1)); +} + +// http://wiki.openstreetmap.org/wiki/Slippy_map_tilenames +void tile2latlon(unsigned int x, unsigned int y, int zoom, double *lat, double *lon) { + unsigned long long n = 1LL << zoom; + *lon = 360.0 * x / n - 180.0; + double lat_rad = atan(sinh(M_PI * (1 - 2.0 * y / n))); + *lat = lat_rad * 180 / M_PI; +} + +void handle(std::string message, int z, unsigned x, unsigned y) { + GOOGLE_PROTOBUF_VERIFY_VERSION; + + // https://github.com/mapbox/mapnik-vector-tile/blob/master/examples/c%2B%2B/tileinfo.cpp + mapnik::vector::tile tile; + + if (is_compressed(message)) { + std::string uncompressed; + decompress(message,uncompressed); + if (!tile.ParseFromString(uncompressed)) { + fprintf(stderr, "Couldn't decompress tile %d/%u/%u\n", z, x, y); + exit(EXIT_FAILURE); + } + } else if (!tile.ParseFromString(message)) { + fprintf(stderr, "Couldn't parse tile %d/%u/%u\n", z, x, y); + exit(EXIT_FAILURE); + } + + for (int l = 0; l < tile.layers_size(); l++) { + mapnik::vector::tile_layer layer = tile.layers(l); + int extent = layer.extent(); + + for (int f = 0; f < layer.features_size(); f++) { + mapnik::vector::tile_feature feat = layer.features(f); + int px = 0, py = 0; + + for (int g = 0; g < feat.geometry_size(); g++) { + uint32_t geom = feat.geometry(g); + uint32_t op = geom & 7; + uint32_t count = geom >> 3; + + if (op == 1 || op == 2) { + if (op == 1) { + printf("\n"); + } + + for (unsigned k = 0; k < count; k++) { + px += dezig(feat.geometry(g + 1)); + py += dezig(feat.geometry(g + 2)); + g += 2; + + long long scale = 1LL << (32 - z); + long long wx = scale * x + (scale / extent) * (px + .5); + long long wy = scale * y + (scale / extent) * (py + .5); + + double lat, lon; + tile2latlon(wx, wy, 32, &lat, &lon); + printf("%f,%f ", lat, lon); + } + } + } + } + } +} + +void decode(char *fname, int z, unsigned x, unsigned y) { + sqlite3 *db; + + if (sqlite3_open(fname, &db) != SQLITE_OK) { + fprintf(stderr, "%s: %s\n", fname, sqlite3_errmsg(db)); + exit(EXIT_FAILURE); + } + + const char *sql = "SELECT tile_data from tiles where zoom_level = ? and tile_column = ? and tile_row = ?;"; + sqlite3_stmt *stmt; + if (sqlite3_prepare_v2(db, sql, -1, &stmt, NULL) != SQLITE_OK) { + fprintf(stderr, "%s: select failed: %s\n", fname, sqlite3_errmsg(db)); + exit(EXIT_FAILURE); + } + + sqlite3_bind_int(stmt, 1, z); + sqlite3_bind_int(stmt, 2, x); + sqlite3_bind_int(stmt, 3, (1LL << z) - 1 - y); + + while (sqlite3_step(stmt) == SQLITE_ROW) { + int len = sqlite3_column_bytes(stmt, 0); + const char *s = (const char *) sqlite3_column_blob(stmt, 0); + + handle(std::string(s, len), z, x, y); + } + + sqlite3_finalize(stmt); + + if (sqlite3_close(db) != SQLITE_OK) { + fprintf(stderr, "%s: could not close database: %s\n", fname, sqlite3_errmsg(db)); + exit(EXIT_FAILURE); + } +} + +void usage(char **argv) { + fprintf(stderr, "Usage: %s file.mbtiles zoom x y\n", argv[0]); + exit(EXIT_FAILURE); +} + +int main(int argc, char **argv) { + extern int optind; + // extern char *optarg; + int i; + + while ((i = getopt(argc, argv, "")) != -1) { + usage(argv); + } + + if (argc != optind + 4) { + usage(argv); + } + + decode(argv[optind], atoi(argv[optind + 1]), atoi(argv[optind + 2]), atoi(argv[optind + 3])); + + return 0; +}