Abstract:
Traditionally, high-performance mapping and 3D visualization has been the preserve of desktop GIS linked to large databases managed in data servers. In recent years, an alternative architecture has emerged that provides some of the same capabilities but through a desktop viewer interacting with an internet-accessible centralized server. A number of these systems have been developed, including ESRI Globe, Google Earth, NASA World Wind, and Skyline TerraExplorer. Technically-speaking, these systems have three key elements: a global database with a raster map and selected vector data; a server able to render views of the globe; and a viewer that can make requests to the server for views to be cached and rendered.
These systems have implemented a solution to a tightly-defined problem: visualizing large quantities of static 2D/3D data in near real-time over the web. Each system has a proprietary desktop application that can be downloaded via the internet and a collection of free services. The base data (DEM, satellite images) are typically those that are freely available, so coverage is initially restricted to world areas with inexpensive data. Capabilities vary from simple 3D viewing to queries and limited analysis.
The advent of geographic earth explorers raises numerous GIS questions: Are these really GIS or simply graphic viewers? Will GIS look like this in a few years? Can I expect a GIS that does editing, data management, spatial analysis and modeling, cartography to be this much fun to use, fast and cheap? How do I leverage existing GIS data and functionality?
