Guided Tour of MPCluster: Setting Limits on Cluster Sizes
MPCluster supports a number of constraints that can be applied to the number and size of the clusters that it finds.
MPCluster's Cluster Options
The various cluster options are set in the lower left of MPCluster's main panel.
The first option lets you specify the maximum number of clusters to find. There is no guarantee that MPCluster will find this many clusters.
Whilst searching for clusters, MPCluster may find it has a cluster that is empty (ie. contains no data points) or has less than the minimum requested number of data points. These clusters are not considered valid and will be ignored when the results are plotted. However, it is possible to re-allocate these empty clusters onto new areas of the map where they might find enough pushpins to make a valid cluster.
Cluster Size Options
The remaining three options all control the size of the clusters that MPCluster reports.
The image to the right shows the effect of increasing the cluster maximum radius. The red cluster has a maximum radius of 15 miles. This has been increased to 40 miles for the green cluster. Note that the new (green) cluster is so much larger that it now includes a lot of restaurants in the Norwich area. This has the effect of moving the cluster's center from the red circle pushpin to the green circle pushpin.
It is also possible to specify the minimum distance between cluster sizes.
The image on the right shows two clusters in red. A minimum distance between cluster centers has been specified for the green clusters. This has the result of pushing the south eastern cluster center to the lower right. The clusters have been defined with a maximum size and number of pushpins, hence the displaced cluster now includes the pushpins located on Galveston Island.
You can also control the size of the clusters by setting the maximum and minimum number of data points in a cluster. All of these constraints are optional: you can apply any combination or none at all.
Next, we look at the MPCluster display settings.