Relief Map

Splashery stretches a drumhead over this Splash's outline, twelve inches across, and finds the ways it can ring. Its lowest is 406.1 Hz, 61 cents sharp of G4, the nearest tine on the comb. The next fifteen are its overtones, and each one draws its own figure: sand gathers on the lines that stay still.

Tap to send a contour line up the cliffs and water down the streams. Change the map and layers in the Splash tab.

A relief map shows the shape of the land. Contour lines join points of the same height: here one every 100 meters, with a heavier line every 500, so lines close together mean a steep slope. This is Yosemite Valley in California, about 18 by 11 kilometers, with El Capitan and Half Dome rising more than 1,000 meters above the Merced River.

The heights come from the U.S. Geological Survey's 3D Elevation Program, and the streams from the National Hydrography Dataset. In the Splash tab, Map switches between height colors, the aerial photo and land cover (forest, meadow, bare rock and buildings, from the National Land Cover Database), and the switches turn the contour lines and streams on and off. Tap it and a glowing contour climbs from the valley floor to the rim while light runs down every stream, the way the water flows.

This link opens it in the Playground. To put it on your own page, add the element and one script tag. Every option.