Title: DBSCAN Clustering
Slug: dbscan_clustering
Summary: How to conduct DBSCAN clustering in scikit-learn.
Date: 2017-09-22 12:00
Category: Machine Learning
Tags: Clustering
Authors: Chris Albon

Preliminaries



In [9]:

    
# Load libraries
from sklearn import datasets
from sklearn.preprocessing import StandardScaler
from sklearn.cluster import DBSCAN

Load Iris Flower Dataset



In [10]:

    
# Load data
iris = datasets.load_iris()
X = iris.data

Standardize Features



In [11]:

    
# Standarize features
scaler = StandardScaler()
X_std = scaler.fit_transform(X)

Conduct Meanshift Clustering

DBSCAN has three main parameters to set:

eps: The maximum distance from an observation for another observation to be considered its neighbor.
min_samples: The minimum number of observation less than eps distance from an observation for to be considered a core observation.
metric: The distance metric used by eps. For example, minkowski, euclidean, etc. (note that if Minkowski distance is used, the parameter p can be used to set the power of the Minkowski metric)

If we look at the clusters in our training data we can see two clusters have been identified, 0 and 1, while outlier observations are labeled -1.



In [12]:

    
# Create meanshift object
clt = DBSCAN(n_jobs=-1)

# Train model
model = clt.fit(X_std)