private static void FillAreas(Relation relation, List <CoordinateSequence> rings, List <Area> areas)
{
while (rings.Any())
{
// find an outer ring
CoordinateSequence outer = null;
foreach (CoordinateSequence candidate in rings)
{
bool containedInOtherRings = false;
foreach (CoordinateSequence other in rings)
{
if (other != candidate && other.ContainsRing(candidate))
{
containedInOtherRings = true;
break;
}
}
if (containedInOtherRings)
{
continue;
}
outer = candidate;
break;
}
// find inner rings of that ring
var inners = new List <CoordinateSequence>();
foreach (CoordinateSequence ring in rings)
{
if (ring != outer && outer.ContainsRing(ring))
{
bool containedInOthers = false;
foreach (CoordinateSequence other in rings)
{
if (other != ring && other != outer && other.ContainsRing(ring))
{
containedInOthers = true;
break;
}
}
if (!containedInOthers)
{
inners.Add(ring);
}
}
}
// create a new area and remove the used rings
var holes = new List <List <GeoCoordinate> >(inners.Count);
foreach (CoordinateSequence innerRing in inners)
{
holes.Add(innerRing.Coordinates);
}
// TODO investigate case of null/empty tags
var tags = GetTags(relation, outer);
if (tags != null && tags.Any())
{
areas.Add(new Area()
{
Id = outer.Id,
Tags = tags.AsReadOnly(),
Points = outer.Coordinates,
Holes = holes
});
}
rings.Remove(outer);
// remove all innerRings
foreach (var nodeSequence in inners)
{
rings.Remove(nodeSequence);
}
}
}
