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Make duplicate trimming less bad: only trim features indexed >1 time

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This commit is contained in:
Eric Fischer
2014-11-06 11:27:10 -08:00
parent 7f6a5dc005
commit ea292def47
3 changed files with 49 additions and 33 deletions
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geojson.c
+42 -29
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@@ -448,39 +448,52 @@ void read_json(FILE *f, char *fname, char *layername, int maxzoom, int minzoom,
ix.maxzoom = z;
fwrite_check(&ix, sizeof(struct index), 1, indexfile, fname, jp);
} else {
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.
int pass;
int instances = 0;
// 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
for (pass = 0; pass < 2; pass++) {
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 >= ((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;
// 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;
}
}
if (pass == 0) {
instances++;
if (instances > 1) {
break;
}
} else {
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.type = mb_geometry[t];
ix.maxzoom = z;
ix.candup = (instances > 1);
fwrite_check(&ix, sizeof(struct index), 1, indexfile, fname, jp);
}
}
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.type = mb_geometry[t];
ix.maxzoom = z;
fwrite_check(&ix, sizeof(struct index), 1, indexfile, fname, jp);
}
}
}