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Reset counter with each tile, to match old low-zoom feature density

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This commit is contained in:
Eric Fischer 2016-10-12 09:49:25 -07:00
parent 81d8fe21f8
commit 081e330845
2 changed files with 25 additions and 1 deletions
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25
main.cpp
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@ -217,15 +217,38 @@ struct drop_state {
double scale;
double seq;
long long included;
unsigned x;
unsigned y;
};
int calc_feature_minzoom(struct index *ix, struct drop_state *ds, int maxzoom, int basezoom, double droprate, double gamma) {
int feature_minzoom = 0;
unsigned xx, yy;
decode(ix->index, &xx, &yy);
if (gamma >= 0 && (ix->t == VT_POINT ||
(additional[A_LINE_DROP] && ix->t == VT_LINE) ||
(additional[A_POLYGON_DROP] && ix->t == VT_POLYGON))) {
for (ssize_t i = maxzoom; i >= 0; i--) {
// XXX This resets the feature counter at the start of each tile,
// which makes the feature count come out close to what it is if
// feature dropping happens during tiling. It means that the low
// zooms are heavier than they legitimately should be though.
{
unsigned xxx = 0, yyy = 0;
if (i != 0) {
xxx = xx >> (32 - i);
yyy = yy >> (32 - i);
}
if (ds[i].x != xxx || ds[i].y != yyy) {
ds[i].seq = 0;
ds[i].gap = 0;
ds[i].previndex = 0;
}
ds[i].x = xxx;
ds[i].y = yyy;
}
ds[i].seq++;
}
for (ssize_t i = maxzoom; i >= 0; i--) {
@ -836,6 +859,8 @@ void prep_drop_states(struct drop_state *ds, int maxzoom, int basezoom, double d
ds[i].scale = (double) (1LL << (64 - 2 * (i + 8)));
ds[i].seq = 0;
ds[i].included = 0;
ds[i].x = 0;
ds[i].y = 0;
}
}

1
tile.cpp
View File

@ -596,7 +596,6 @@ long long write_tile(FILE *geoms, long long *geompos_in, char *metabase, char *s
double accum_area = 0;
double interval = 0;
double seq = 0;
if (z < basezoom) {
interval = std::exp(std::log(droprate) * (basezoom - z));
}