Server side clusters of coordinates based on zoom level

Question

Thanks to this answer I managed to come up with a temporary solution to my problem.

However, with a list of 6000 points that grows everyday it's becoming slower and slower.

I can't use a third party service* therefore I need to come up with my own solution.

Here are my requirements:

1. Clustering of the coordinates need to work with any zoom level of the map.

2. All clusters need to be cached

3. Ideally there won't be a need to cluster (calculate distances) on all points if a new point is added.

So far I have implemented quadtree that returns the four boundaries of my map and returns whatever coordinates are within the viewable section of the map.

What I need and I know this isn't easy is to have clusters of the points returned from the DB (postgres).

Answer 1

I don't see why you have to "cluster" on the fly. Summarize at each zoom level at a resolution you're happy with.

Simply have a structure of X, Y, # of links. When someone adds a link, you insert the real locations (Zoom level max, or whatever), then start bubbling up from there.

Eventually you'll have 10 sets of distinct coordinates if you have 10 zoom levels - one for each different zoom level.

The calculation is trivial, and you only have to do it once.

Answer 2

I am currently doing dynamic server-side clustering of about 2,000 markers, but it runs pretty quick up to 20,000. You can see discussion of my algorithm here:

Map Clustering Algorithm

Whenever the user moves the map I send a request with the zoom level and the boundaries of the view to the server, which clusters the viewable markers and sends it back to the client.

I don't cache the clusters because the markers can be dynamically filtered and searched - but if they were pre-clustered it would be super fast!