(Lat, lon) points fast clustering using DBScan algorithm in Go.

Given set of geo points, this library can find clusters according to specified params. There are several optimizations applied:

• distance calculation is using "fast" implementations of sine/cosine, with sqrt being removed
• to find points within eps distance k-d tree is being used
• edge case handling of identical points being present in the set

Build list of points:

    points := cluster.PointList{{30.258387, 59.951557}, {30.434124, 60.029499}, ...}

Pick settings for DBScan algorithm:

• eps is clustering radius (in kilometers)
• minPoints is number of points in eps-radius of base point to consider it being part of the cluster

eps and minPoints together define minimum density of the cluster.

Run DBScan:

    clusters, noise := cluster.DBScan(points, 0.8, 10) // eps is 800m, 10 points minimum in eps-neighborhood

DBScan function returns list of clusters (each Cluster being reference to the list of source points) and list of point indexes which don't fit into any cluster (noise).