Android Maps utils上的Quadtree

Question

I'm developing a android application with google maps v2 that draw polygons on the google maps. But now i have to identify a click on a certain polygon and popup a window.

I found this useful library on github

This library has the method containsLocation implemented. This method receives a LatLng (from click on the map) and a List (the polygon). This is fine but if i have 1 million polygon in the map i cant iterate all and test if a certain LatLng belongs to a certain Polygon. I remember that i can use a quadtree to get more performance and this library also implements a quadtree but it uses point. What is the best way of doing this? May i have to reimplement this quadtree for a quadtree of LatLng ? Or in each click i have to convert this click to a point and search on a point quadtree?

Regards

Answer 1

you cannot use a Point- Quadtree, you need an Object-Quadtree for your Polygons. An object quadree uses the bounding box of the polygon or any object for adding into the tree.

you dont need to consider latLong, use x,y with x= longitude, and y = Latitude.

Consider reading Hanan Sammet: Foundations of multidimensional data structures.

Answer 2

I think you need to implement a quadtree that stores the polygons, then query the tree to see which polygon (if any) contains the LatLng. If you search around I'm sure you can find a decent implementation.