1. A computing device configured to render time-varying geographic data on a map, the computing device comprising: a memory device, and processing hardware configured to: access, from the memory device, data defining a three-dimensional object representing time-varying geographic data, the three-dimensional object defined in a three-dimensional coordinate space, the geographic data including at least one variable that varies in magnitude at a time-varying location in the coordinate space, determine a two-dimensional plane in the three-dimensional coordinate space, the two-dimensional plane corresponding to a time value of interest, intersect the three-dimensional object with the two-dimensional plane to define a shape, and render, on the map, the shape defined by the intersection of the two-dimensional plane with the three-dimensional object to illustrate a location on the map and a magnitude of the variable corresponding to the time value of interest.