Geologic Survey Topographic Maps USGS Quads meet these criteria and also show a tremendous amount of base data, land cover, streams and other water features, roads, buildings, pipelines, bathymetry, etc. Elevation is shown on maps called contour maps. Lines of elevation are contour lines , a type of isoline.
Contour lines connect points of equal elevation.
The datum is 0 elevation, or sea level. The contour interval is constant on each map, but may change from map to map. Therefore, elevation can be measured and interpolated - estimated where no line falls. The National Map Accuracy Standard specifies that you must be able to interpolate elevation to within one half of the contour interval. Scale Topographic Maps come in several different scales.