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MPCluster for Maptitude

Navigation: Running MPCluster

Calculating Overlay Fields

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MPCluster has the ability to apply an 'overlay' between the cluster boundary shapes and a point layer. This overlay finds all of the point layer's locations that are with each boundary shape and calculates sums and/or counts of the layer's data fields. These are then written to the boundary shape. For example, the point layers could show customers and include a "purchases" field. The overlay functionality can then be used to report the total purchases and total number of customers within each cluster. Further information on overlays can be found in the Maptitude documentation and on our Overlays page on the Maptitude HowTo.. section of the Mapping-Tools.com website.

 

Enable the Overlay functionality by setting the Calculate Overlay Fields check box in the Display Options:

 

main_panel_overlay

 

You will need to have the Write clusters to layers checkbox set in order to enable this option. Press the Overlay button to set the various overlay settings on the Overlay Output Options dialog box:

 

overlay_dlg

 

Select the point layer using the Overlay Dataset drop down list. You can select the same layer as MPCluster's input layer, but you do not have to. When you select an overlay dataset, the list will fill with a list of the layer's available data fields. Set the check boxes for those fields that you would like to calculate a count and/or sum for. Note that some options will be disabled. For example, you can count identifier fields (e.g. text and integers) but not floating point (real) fields. Similarly, you can sum numeric (real or integer) fields, but not text fields. The above dialog box is set to count the unique zipcodes and to sum the total populations within each cluster.

 

Press OK when you have selected the required field calculations.

 

Here are the results for a boundary layer, displayed as a data view to show the calculated columns:

 

overlay_dataview

 

This data view shows the two columns produced by the Overlay Output Options dialog box above. This  creates an overlay from Maptitude's own zipcode layer (5-digit ZIP Code). The Count_Name column counts the unique Name values contained within each cluster. The Sum_Population field reports the total population for each cluster. This is created by summing the Population field in the 5-digit ZIP Code layer.