Ancient Web: Fourmilab's Earth Viewer Put the Planet on the Web in 1994

Part of the Ancient Web Collection.

In December 1994, asking a website to show the Earth from a particular position was a rather exotic thing to do. Fourmilab's Earth Viewer was already figuring out where the planet's night side belonged and drawing pictures on demand.

Explore the Earth and Moon Viewer.

The author is John Walker, a cofounder of Autodesk and the creator of several free astronomy and computing projects. According to the program's own credits, Earth Viewer was first implemented in December 1994 and extended to the Moon in October 1996.

A browser interface to real calculations

A visitor can request the globe from the Sun, Moon, a point above Earth's surface, an orbiting satellite, or various cities. The program also generates maps of the boundary between day and night. Earth images may be based on topography, satellite observations, nighttime city lights, and cloud cover.

The Moon has its own modes: view it from Earth or the Sun, center named lunar formations, and compare its changing distance from Earth. Later additions extend the same idea to Mercury, Venus, Mars and its moons, asteroids, and Pluto.

Behind the scenes is a revealing genealogy of early internet software. The credits name Walker's Home Planet program, Robert Berger's N3EMO satellite routines, Jef Poskanzer's pbmplus, and the Independent JPEG Group's image software. The early Earth imagery had to be compressed and reduced to manageable sizes before it could be generated interactively on a server.

The resource did not remain technologically frozen. Its credits now describe NASA Blue Marble and Black Marble imagery, global topographic data, and cloud information processed from satellite composites. A 2006 developer update records a server-side revision intended to make the interactive resource run more efficiently.

This is not a single unchanging image from 1994. It is a long-lived application whose original idea survived multiple generations of graphics sources and server hardware.

A modern mapping app can place a rotatable planet on the screen effortlessly. Fourmilab's old-fashioned lists and custom image requests show the earlier step: a website acting as a remote graphics workstation for someone who wanted to look at the world from somewhere else.

Explore the original viewing modes and credits.

Part of the Ancient Web Collection.