MATLAB: Core points of clusters

core pointsdbscanStatistics and Machine Learning Toolbox

I need to find the center points of a clusters. I used dbscan for clustering. Now I need to find the core points of these clusters. I used the corepts,but it gives the logical array. How can I find the core points of those clusters or atleast a point contained in those clusters. Anybody please help me.
[idx, corepts] = dbscan(asc,epsilon,minpts);

Best Answer

As discussed here, https://stackoverflow.com/questions/52364959/how-to-find-center-points-of-dbscan-clusrering-in-sklearn and here https://www.quora.com/Is-there-anything-equivalent-to-a-centroid-in-DBSCAN, dbscan does not have a center of the cluster. However, it does generate core points. You can get the core points by modifying the line in your code
core = data(corepts, :);
It will give you all rows conntaining core points. Similarly you can get the cluster number of these core points
corr_idx = idx(corepts, :);
As an example, try this
data=xlsread('glass.xlsx');
minpts=6;
epsilon=4;
[idx, corepts] = dbscan(data,epsilon,minpts);
fig1 = figure();
gscatter(data(:,1),data(:,2),idx);
fig2 = figure();
core=data(corepts, :);
corr_idx = idx(corepts, :);
gscatter(core(:,1),core(:,2),corr_idx);
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