I would use a r-tree or a database that implements one for geo spacial queries. http://en.m.wikipedia.org/wiki/Spatial_database On Mar 18, 2014 8:32 PM, "S. Dale Morrey" <sdalemor...@gmail.com> wrote:
> I have a resource constrained system that contains a map and a list of > points on the map given as longitude and latitude. > Each point is it's own seperate object. > I also have a point on the map that corresponds to the user's current > location. > > What I want to do is search all of the points in the map and return the one > closest to the user. > The long and lat are both signed doubles (language is Java but the > principles should basically be the same). > > What would be the optimal search given that the list of points is contained > in a Vector (array). > I'm thinking something like a loop that goes through each item and compares > the long and lat differences for the smallest differences. But that seems > to me like a suboptimal solution. > I have access to background threads and I do wonder about maybe 2 threads > doing this, but one counting from the front of the array and another > counting from the back. At present there are only a couple of hundred > points, but it's possible in the future that the list might balloon to > thousands. > > Anyways just hoping someone knows of a better search method. > > /* > PLUG: http://plug.org, #utah on irc.freenode.net > Unsubscribe: http://plug.org/mailman/options/plug > Don't fear the penguin. > */ > /* PLUG: http://plug.org, #utah on irc.freenode.net Unsubscribe: http://plug.org/mailman/options/plug Don't fear the penguin. */
