- FGPositioned::List result;
- int radius = 1; // start at 1, radius 0 is handled explicitly
- SGBucket buck;
- double lat = aPos.getLatitudeDeg(),
- lon = aPos.getLongitudeDeg();
- // final cutoff is in metres, and scaled to account for testing the corners
- // of the 'box' instead of the centre of each edge
- double cutoffM = aCutoffNm * SG_NM_TO_METER * 1.5;
-
- // base case, simplifes loop to do it seperately here
- spatialFilterInBucket(sgBucketOffset(lon, lat, 0, 0), aFilter, result);
-
- for (;result.size() < aN; ++radius) {
- // cutoff check
- double az1, az2, d1, d2;
- SGGeodesy::inverse(aPos, sgBucketOffset(lon, lat, -radius, -radius).get_center(), az1, az2, d1);
- SGGeodesy::inverse(aPos, sgBucketOffset(lon, lat, radius, radius).get_center(), az1, az2, d2);
-
- if ((d1 > cutoffM) && (d2 > cutoffM)) {
- //std::cerr << "spatialGetClosest terminating due to range cutoff" << std::endl;
- break;
- }
-
- FGPositioned::List hits;
- for ( int i=-radius; i<=radius; i++) {
- spatialFilterInBucket(sgBucketOffset(lon, lat, i, -radius), aFilter, hits);
- spatialFilterInBucket(sgBucketOffset(lon, lat, -radius, i), aFilter, hits);
- spatialFilterInBucket(sgBucketOffset(lon, lat, i, radius), aFilter, hits);
- spatialFilterInBucket(sgBucketOffset(lon, lat, radius, i), aFilter, hits);
- }
-
- result.insert(result.end(), hits.begin(), hits.end()); // append
- } // of outer loop
-
- sortByDistance(aPos, result);
- if (result.size() > aN) {
- result.resize(aN); // truncate at requested number of matches
- }
-
- return result;