PRINCIPLES, METHODOLOGIES AND APPLICATION OF REMOTELY SENSED DATA FOR DEVELOPING LAND COVER CHARACTERISTICS DATA SET FOR NECT Combining multitemporal NOAA-AVHRR NDVI and ground auxiliary data for estimating terrestrial net primary production in Guangdong Estimation of radiation absorption by Guangdong vegetation using GIS and RS Estimation of Solar Energy Use Efficiency and Spatiotemporal Pattern in Guangdong Based on Multitemporal NOAA-AVHRR NDVI and GIS Methods