ExternalVendorCode/tippecanoe
1
0
Fork 0
mirror of https://github.com/mapbox/tippecanoe.git synced 2025-04-04 17:49:06 +00:00
Code Issues Actions Packages Projects Releases Wiki Activity

The indexing side of buffering features at the edges of tiles

Browse Source
This commit is contained in:
Eric Fischer 2014-10-27 12:56:51 -07:00
parent e0826a12c6
commit 4cb56a6b11
3 changed files with 37 additions and 10 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

42
geojson.c
View File

@ -342,6 +342,7 @@ void read_json(FILE *f, char *fname, char *layername, int maxzoom, int minzoom,
}
int z = maxzoom;
int buffer = 10;
unsigned cx = bbox[0] / 2 + bbox[2] / 2;
unsigned cy = bbox[1] / 2 + bbox[3] / 2;
@ -353,18 +354,39 @@ void read_json(FILE *f, char *fname, char *layername, int maxzoom, int minzoom,
ix.fpos = start;
fwrite_check(&ix, sizeof(struct index), 1, indexfile, fname, jp);
} else {
unsigned x, y;
for (x = bbox[0] >> (32 - z); x <= bbox[2] >> (32 - z); x++) {
for (y = bbox[1] >> (32 - z); y <= bbox[3] >> (32 - z); y++) {
struct index ix;
for (z = maxzoom; z >= 1; z--) {
unsigned x, y;
for (x = (bbox[0] - (buffer << (32 - z - 8))) >> (32 - z); x <= (bbox[2] + (buffer << (32 - z - 8))) >> (32 - z); x++) {
for (y = (bbox[1] - (buffer << (32 - z - 8))) >> (32 - z); y <= (bbox[3] + (buffer << (32 - z - 8))) >> (32 - z); y++) {
if (z != maxzoom) {
// There must be a clearer way to write this, but the intent is
// not to add an additional index for a low-zoom tile
// if one of its children was already part of the
// buffered bounding box for the child's zoom.
if (x == cx >> (32 - z) && y == cy >> (32 - z)) {
ix.index = encode(cx, cy);
} else {
ix.index = encode(x << (32 - z), y << (32 - z));
// So we are comparing this tile's x and y to the edges of the
// bounding box at the next zoom down, but divided by two
// to get it back into this zoom's tile coordinate scheme
if ((x >= ((bbox[0] - (buffer << (32 - (z + 1) - 8))) >> (32 - (z + 1)) >> 1)) &&
(x <= ((bbox[2] + (buffer << (32 - (z + 1) - 8))) >> (32 - (z + 1)) >> 1)) &&
(y >= ((bbox[1] - (buffer << (32 - (z + 1) - 8))) >> (32 - (z + 1)) >> 1)) &&
(y <= ((bbox[3] + (buffer << (32 - (z + 1) - 8))) >> (32 - (z + 1)) >> 1))) {
continue;
}
}
struct index ix;
if (x == cx >> (32 - z) && y == cy >> (32 - z)) {
ix.index = encode(cx, cy);
} else {
ix.index = encode(x << (32 - z), y << (32 - z));
}
ix.fpos = start;
ix.maxzoom = z;
fwrite_check(&ix, sizeof(struct index), 1, indexfile, fname, jp);
}
ix.fpos = start;
fwrite_check(&ix, sizeof(struct index), 1, indexfile, fname, jp);
}
}
}

4
tile.cc
View File

@ -366,6 +366,10 @@ long long write_tile(struct index *start, struct index *end, char *metabase, uns
struct index *i;
for (i = start; i < end; i++) {
if (z > i->maxzoom) {
continue;
}
struct pool_val *pv = pool_long_long(&dup, &i->fpos, 0);
if (pv->n == 0) {
continue;

1
tile.h
View File

@ -20,6 +20,7 @@ struct pool_val *deserialize_string(char **f, struct pool *p, int type);
struct index {
unsigned long long index;
long long fpos;
int maxzoom;
};
long long write_tile(struct index *start, struct index *end, char *metabase, unsigned *file_bbox, int z, unsigned x, unsigned y, int detail, int basezoom, struct pool *file_keys, char *layername, sqlite3 *outdb, double droprate);