OSMWithTags areaEntity = group.getSomeOSMObject();
for (int i = 0; i < visibilityNodes.size(); ++i) {
OSMNode nodeI = visibilityNodes.get(i);
VisibilityPolygon visibilityPolygon = new VisibilityPolygon(
visibilityPoints.get(i), areaEnv, VISIBILITY_EPSILON);
Polygon poly = toJTSPolygon(visibilityPolygon);
for (int j = 0; j < visibilityNodes.size(); ++j) {
OSMNode nodeJ = visibilityNodes.get(j);
P2<OSMNode> nodePair = new P2<OSMNode>(nodeI, nodeJ);