SPIE Proceedings [SPIE Third International Asia-Pacific Environmental Remote Sensing Remote Sensing of the Atmosphere, Ocean, Environment, and Space - Hangzhou, China (Wednesday 23 October 2002)] Ecosystems Dynamics, Ecosystem-Society Interactions, and Remote Sensing Applications for Semi-Arid and Arid Land - Dynamic monitoring of grassland degradation with remote sensing and the strategy of ecological restoration in Shandan County of Heihe Basin