Related Topics:
	Chart Types

Elevation Charts: Surface and Contour

Elevation charts are commonly used to display topographic data. There are two types of elevation charts: contour charts and 3D surface charts.

A contour chart is drawn as a two-dimensional area. Changes in the data plotted on this chart are demonstrated through variations in color known as contours. Contours are drawn on the chart as either colored bands or lines. Contour bands can be represented on the chart in dramatic contrast or as a subtle transition in hue known as gradient. Contour charts do not have a value axis; the variation in color is represented in the legend instead.

A surface chart is drawn as a rectangular grid with a surface base or floor. The value axis is drawn perpendicular to the chart base giving the chart its three-dimensional quality. Data variations are plotted on this chart at raised elevations from the surface. The data points themselves are plotted on grid intersections at the corresponding value axis elevation, thus giving the chart depth.

Contours can be applied to surface charts to display additional information. These variations in color bands or lines are projected on the chart's three-dimensional surface and can demonstrate a separate collection of data independent of elevation.