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FindClusterAtPos


Unit:SDL_dendrogram
Class:TDendrogram
Declaration:function FindClusterAtPos (X,Y: integer): integer;

The function FindClusterAtPos returns the cluster index of the dendrogram line closest to the position [X,Y]. The parameters X and Y are pixel coordinates (as, for example, delivered by the OnMouseDown event). Cluster indexes between 1 and Data.NrOfRows designate a data point, indexes above indicate a sub-cluster.

The selectivity ranges of the individual dendrogram lines are controlled by two rules: (1) the X value is checked against the X range of all dendrogram lines. Those lines for which X is within their X range qualify for the second rule. (2) The distances between Y and the lines which qualify from rule (1) are calculated. The line showing the smallest distance is finally selected and its cluster index returned. The figure at the right shows the selectivity ranges for a sample dendrogram.



Last Update: 2014-Jun-02