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Is the distance between two points in a cluster?
In single linkage hierarchical clustering, the distance between two clusters is defined as the shortest distance between two points in each cluster. For example, the distance between clusters “r” and “s” to the left is equal to the length of the arrow between their two closest points.
What are cluster points?
Definition: cluster at a point. A set, or sequence, A⊆(S,ρ) is said to cluster at a point p∈S (not necessarily p∈A), and p is called its cluster point or accumulation point, iff every globe Gp about p contains infinitely many points (respectively, terms of A.
What measures the goodness of a cluster?
Cohesion measures the goodness of a cluster.
How to cluster a list of geographic points by distance?
Using Python 3, I would like to find a smallest set of clusters (disjoint subsets of P) such that every member of a cluster is within 20km of every other member in the cluster. Distance between two points is computed using the Vincenty method. To make this a little more concrete, suppose I have a set of points such as
Which is the best algorithm for clustering coordinates?
Since your data is in latitude, longitude format, you should use an algorithm that can handle arbitrary distance functions, in particular geodetic distance functions. Hierarchical clustering, PAM, CLARA, and DBSCAN are popular examples of this.
How to set the distance of a cluster in Java?
The following psuedocode should do the trick: Java Apache commons-math does this pretty easily. @CKM there is a parameter in HDBSCAN package: cluster_selection_epsilon which allows you to set the acceptable distance for the neighboring points in the same cluster (just like epsilon in DBSCAN).
How to find the optimal number of clusters?
Since k-means tries to group based solely on euclidean distance between objects you will get back clusters of locations that are close to each other. To find the optimal number of clusters you can try making an ‘elbow’ plot of the within group sum of square distance.