ABSTRACT
Discovering knowledge from the mass database is the main objective of the Data Mining. Clustering is the key
technique in data mining. A cluster is made up of a number of similar objects grouped together. The clustering is
an unsupervised learning. There are many methods to form clusters. The four important methods of clustering
are Partitional Clustering, Hierarchical Clustering, Density-Based Clustering and Grid-Based Clustering. In this
paper, we discussed these four methods in detail.
Keywords: - Clustering, Density-Based, Fuzzy, Grid-Based, Hierarchical, K-Means, Partitioning, STING, Wavelet.