/// <summary> /// Filters out only objects in a person's direction of a view /// </summary> private IEnumerable <string> FilterObjectsByPositionAndBearing(OsmObjectsOfImportance objects, GeoPoint position, double bearing) { Debug.Assert(objects != null, "objects == null"); Debug.Assert(position != null, "position == null"); var testingPoints = GetPointsAlongBearing(position, bearing); // filter objects var filterSingleNodesTask = Task.Factory.StartNew(() => FilterSingleNodes(objects.SingleNodes, testingPoints)); var filterBuildingsWaysTask = Task.Factory.StartNew(() => { // filter buildings' ways by testing if some point along a person's direction of view is inside the way foreach (var point in testingPoints) { foreach (var way in objects.BuildingsWays) { if (GeoCalc.IsPointInsidePolygon(point, way.Nodes)) { return new { TestingPoint = point, Way = way } } ; } } return(null); }); Task.WaitAll(filterSingleNodesTask, filterBuildingsWaysTask); // print out objects' descriptions var building = filterBuildingsWaysTask.Result; if (building != null) { yield return(BuildingWayDescription(building.Way)); } foreach (var node in filterSingleNodesTask.Result) { if (building == null || GeoCalc.GetDistance(node, building.TestingPoint) < Adjustment.MaxDeviationFromBearingBuildingIntersection) { yield return(SingleNodeDescription(node)); } } }
/// <summary> /// Filters single nodes by testing whether they are close to the points along a person's direction of view /// </summary> private ICollection <OsmNode> FilterSingleNodes(ICollection <OsmNode> singleNodes, IEnumerable <GeoPoint> testingPoints) { Debug.Assert(singleNodes != null, "singleNodes == null"); Debug.Assert(testingPoints != null, "testingPoints == null"); var result = new List <OsmNode>(); foreach (var point in testingPoints) { foreach (var node in singleNodes) { if (!result.Contains(node) && GeoCalc.GetDistance(point, node) < Adjustment.MaxDeviationFromBearing) { result.Add(node); } } } return(result); }