//------------------------------------------------------------------------
double PolylineEncoder::distance(const LatLng &p0, const LatLng &p1, const LatLng &p2)
{
double out = 0.0;
if (p1.lat() == p2.lat() && p1.lng() == p2.lng()) {
out = hdist(p2, p0);
}
else {
double dlat = (p2.lat()-p1.lat());
double dlng = (p2.lng()-p1.lng());
double u = ((p0.lat()-p1.lat())*dlat+(p0.lng()-p1.lng())*dlng)/(dlat*dlat + dlng*dlng);
if (u <= 0) {
out = hdist(p0, p1);
}
else if(u >= 1) {
out = hdist(p0, p2);
}
else {
out = hdist(p0, LatLng(p1.lat() + u*dlat, p1.lng() + u*dlng));
}
}
return out;
}
//------------------------------------------------------------------------
static double hdist(const LatLng &a, const LatLng &b) {
return hypotenuse(a.lat()-b.lat(), a.lng()-b.lng());
}
