In formhub, our map visualizations had so far focused on individual survey points–you saw responses distributed across space, and could click on each response to find out more. Recently, we added spatial summarization through hexbins to the mix. Two varieties exist, one to simply show density of submissions:
And the other, which I think goes much deeper, visualizes the percentage of a response per aggregated unit of space. To use an example, you can see where water points are most disproportionately dysfunctional across space on the formhub map–no GIS expert needed.