3-D data model
Data modeling programs may interpolate data in all three dimensions.  In order to be realistic they require relatively dense arrays of data points.
In this example from a Great Lakes harbor,  lead concentrations in a sediment deposit were modeled in 3D using about 150 data points representing 10 vibracores collected within an area of roughly 50 x 200 feet.  The color key indicates concentration levels from low (green) to high (purple).  Note the "hot spot" at right center.  The vertical rows of yellow dots represent discrete sub-samples taken within cores.