_______________________________________________Hi Andrea,
Andrea Beconcini Via Geometry wrote:I am trying to use an rtree as an index to a set of triangles to perform some spatial queries.
The rtree stores std::pair<box, triangles> where box is the boost geometry box.
The problem occurs with the nearest query and, in particular, when two or more elements have equivalent boxes,
and I look for just one element, the result may be wrong.
Look at the code below; the problem is that the two triangles have equivalent bounding boxes, and since
the query returns just one element, the result is the one I inserted first. Even though the bounding boxes
are the same, the two elements are not, I'd like the query to returns t2 instead.
I think I need to provide an IndexableGetter to my rtree, but according to
https://www.boost.org/doc/libs/1_70_0/libs/geometry/doc/html/geometry/spatial_indexes/creation_and_modification.html
the returned value has to be one of the Indexable concepts (Point, Box, or Segment) and none of them seems to satisfy
my requirements.
Do I need to make my triangle Indexable? I could not find any reference on how to do that and what methods are required
for a type to be indexable; can anyone provide any resources that may be useful?
No, only boxes should be used for indexing.
You have to iterate the query iterator and check a condition until you're satisfied with the result, e.g.:
double distance_to_closest_triangle = MAX;
for(auto it = rtree.qbegin(nearest(pt, rtree.size())) ; it != rtree.qend() ; ++it) {
if (distance_to_closest_triangle <= distance(pt, it->first))
break;
distance_to_closest_triangle = min(distance(pt, triangles[it->second]), distance_to_closest_triangle);
}
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