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Don't use longitude wraparound detection if it makes a contradictory geometry

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This commit is contained in:
Erica Fischer
2023-12-11 11:00:03 -08:00
parent d7bdbe363b
commit 80ac56a0b3
4 changed files with 99 additions and 27 deletions
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serial.cpp
+76 -27
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@@ -314,40 +314,89 @@ serial_feature deserialize_feature(std::string &geoms, unsigned z, unsigned tx,
}
static long long scale_geometry(struct serialization_state *sst, long long *bbox, drawvec &geom) {
long long offset = 0;
long long prev = 0;
bool has_prev = false;
double scale = 1.0 / (1 << geometry_scale);
if (additional[A_DETECT_WRAPAROUND]) {
drawvec out;
for (size_t i = 0; i < geom.size(); i++) {
if (geom[i].op == VT_MOVETO) {
size_t j = 0;
for (j = i + 1; j < geom.size(); j++) {
if (geom[j].op != VT_LINETO) {
break;
}
}
long long prev_x = geom[i].x;
long long offset = 0;
bool balanced = true;
drawvec ring;
for (size_t k = i; k < j; k++) {
draw op = geom[k];
op.x += offset;
// jumps at least 180° but not exactly 360°,
// which in some data sets is an intentional
// line across the world
if (op.x - prev_x > (1LL << 31) && op.x - prev_x != (1LL << 32)) {
if (offset < 0) {
// already shifted left, but seems to need another shift left
balanced = false;
break;
}
offset -= 1LL << 32;
op.x -= 1LL << 32;
} else if (prev_x - op.x > (1LL << 31) && prev_x - op.x != (1LL << 32)) {
if (offset > 0) {
// already shifted right, but seems to need another shift right
balanced = false;
break;
}
offset += 1LL << 32;
op.x += 1LL << 32;
}
ring.push_back(op);
prev_x = op.x;
}
if (geom[j - 1] == geom[i]) {
if (offset != 0) {
// first and last points are supposed to be the same
// but there is an unresolved antimeridian shift still
balanced = false;
}
}
if (!balanced) {
ring.clear();
for (size_t k = i; k < j; k++) {
ring.push_back(geom[k]);
}
}
for (auto const &g : ring) {
out.push_back(g);
}
i = j - 1;
} else if (geom[i].op == VT_CLOSEPATH) {
out.push_back(geom[i]);
}
}
geom = std::move(out);
}
for (size_t i = 0; i < geom.size(); i++) {
if (geom[i].op == VT_MOVETO || geom[i].op == VT_LINETO) {
long long x = geom[i].x;
long long y = geom[i].y;
if (additional[A_DETECT_WRAPAROUND]) {
if (geom[i].op == VT_LINETO) {
x += offset;
if (has_prev) {
// jumps at least 180° but not exactly 360°,
// which in some data sets is an intentional
// line across the world
if (x - prev > (1LL << 31) && x - prev != (1LL << 32)) {
offset -= 1LL << 32;
x -= 1LL << 32;
} else if (prev - x > (1LL << 31) && prev - x != (1LL << 32)) {
offset += 1LL << 32;
x += 1LL << 32;
}
}
has_prev = true;
prev = x;
} else {
offset = 0;
prev = x;
}
}
if (x < bbox[0]) {
bbox[0] = x;
}