specify the number of clusters in dbscan

how to specify the number of clusters in dbscan please ????

Answer 1

[VM Sreeram]

It is not possible to specify the number of clusters as a parameter in dbscan. The number of clusters is automatically determined by the algorithm based on the density of data points in the feature space.

However, the density and hence the number of resulting clusters may be indirectly controlled by adjusting the two parameters epsilon (defines the neighborhood search radius around a point) and minpts (the minimum number of neighbors required for a core point) of dbscan.

Answer 2

[Image Analyst]

Like @VM Sreeram said, you can't do that directlywith dbscan, though you could iterate varying the parameter until only two clusters are found.

Alternatively you can use kmeans where you can specify the desired number of clusters.