Guided Tour of MPCluster: Shaded Areas
Most of the examples in this guided tour use pushpin (point data), but MPCluster also supports most of MapPoint's dataset types. This includes the useful shaded area dataset type.
Using Shaded Area Datasets
MPCluster lists all usable datasets with the pushpin sets. To use a shaded area dataset, simply select it as the input data.
MPCluster uses the centroid (center) locations for the areas mapped in such datasets. This would result in a clustering of areas (counties in this example), and not the actual data that has been plotted (population in this example). This is solved by selecting the (population) data field for the constraint sum. This tells MPCluster to only create clusters with total field values (ie. total populations) within a specific range.
MPCluster can also use a data field as a weight value. This 'weight' moves each cluster's center towards a natural area of high data values.
Shaded Area Clusters
Here are the results for a shaded area population map using the above parameters. MPCluster has drawn red polygons around each population cluster that has been found.
Note: For area shapes, MPCluster works with respect to centroids (centers) rather than the actual area shapes. This results in the boundary polygon being defined in terms of the area shape centroids. Ie. the boundary line will appear to bisect areas which, in reality, are fully enclosed in the result cluster.
Next, we look at how to set limits on the cluster sizes.