MapShape Intersections

[Simon]

I would like to more accurately determine if a Location is in a MapShape, or whether two MapShape intersect each other.

At present, I use something like

LocationRect? selectionRect = null;
foreach(MapShape shape in Items)
{
  LocationRect shapeLocationRect = shape.GeographicalBounds;
  shapeLocationRect.MapControl = MapControl;
  if (shapeLocationRect.Contains(location))
  {
    selectionRect = shapeLocationRect;
    break;
  }
}

This only uses the bounding rectangle, so if I have a MapPolygon, then I can possibly get a hit outside of the actual shape boundaries

The problem becomes more compounded when I need to look for the intersection of two shapes

foreach (var layerItem in layer.Items)
{
    if (layerItem is MapShape)
    {
        MapShape mapShape = (MapShape)layerItem;
        if (selectionRect.HasValue && mapShape.GeographicalBounds.Intersect(selectionRect.Value))
        {
        }
    }
}

One point to note is that because I only have MapPolygons ort MapPaths in my layer I can check the GeographicalBounds for the Intesection.  If I have MapRectangles or MapEllipses then I do not get a hit, unless I set the MapControl.

Hope you can help
Thanks
Simon

[Andrey]

Hello Simon,

To detect whether a location is inside the shape you can use code similar to the following:

private bool IsInShape(Location location, MapShape desiredShape)
{
    bool isInside = false;

    IEnumerable<object> list = this.informationLayer.GetItemsInLocation(location);
    foreach (object item in list)
    {
        MapShape shape = item as MapShape;
        if (shape != null && shape == desiredShape)
        {
            isInside = true;
            break;
        }
    }
    return isInside;
}


private MapShape GetShapeByLocation(Location location)
{
    MapShape containedShape = null;

    IEnumerable<object> list = this.informationLayer.GetItemsInLocation(location);
    foreach (object item in list)
    {
        MapShape shape = item as MapShape;
        if (shape != null)
        {
            containedShape = shape;
            break;
        }
    }

    return containedShape;
}

Unfortunately there is no better approach to detect intersection of 2 map shapes currently and this task does not seem to be a trivial one. For now we do not have plans to implement this functionality, but I will make sure it is reconsidered when discussing our future plans.

All the best,
Andrey Murzov
the Telerik team

[Simon]

Thanks for the solution above.

For intersecting mapshapes I recreated the same MapGeometry in Geometry, and then used the FillContainsWithDetail method