DBSCAN: Intution, Advantages, and Points to Remember

Rahul S
3 min readSep 15, 2023


Imagine you have a field of stars in the night sky, and you want to group them based on how densely they are packed together rather than a predetermined number of clusters. This is where DBSCAN, which stands for Density-Based Spatial Clustering of Applications with Noise, shines like a cosmic beacon.

DBSCAN is a remarkable clustering algorithm that doesn’t rely on predefining the number of clusters, making it particularly well-suited for finding clusters of varying shapes and sizes in your data.


Here’s how DBSCAN works:

  1. Density-Centered Clustering: DBSCAN identifies clusters by looking at the density of data points. It defines a cluster as a dense region of data points that is separated by areas of lower point density.
  2. Core Points: The algorithm starts by selecting a random data point and examines its neighborhood within a specified radius (epsilon, ε). If there are at least a minimum number of data points (minPts) within this neighborhood, it marks the central point as a “core point.”
  3. Growing Clusters: DBSCAN then expands the cluster around this core point by recursively adding nearby points that are also core points. This process continues until no more core points can be added.
  4. Border Points: Any data points that are within the neighborhood of a core point but don’t meet the density criteria to be core points themselves are considered “border points” and are assigned to the nearest cluster.
  5. Noise: Data points that are not core points or border points and are not within the neighborhood of any core points are treated as noise and do not belong to any cluster.


Now, let’s explore some of the benefits of DBSCAN over other clustering algorithms:

1. No Predefined Number of Clusters: One of the most significant advantages of DBSCAN is that you don’t need to specify the number of clusters beforehand. It adapts to the density and distribution of data, making it useful when you have no prior knowledge of the dataset’s structure.