Research on the capabilities of ERS-SAR for monitoring of land use changes in the neotropics

Land use maps at a scale of 1:200.000 exist for the whole of Costs Rica. They were produced in 1985 from Landsat-TM images and aerial photographs. Given the frequent cloud cover, regular updating of those maps via optical satellite data is problematic. The north-east of Costs Rica is a region with a nearly flat relief and some isolated hills. Most of the land is covered with pasture and wet tropical forest. During the last decade a significant portion of the area has been converted into plantations, mostly of banana. A procedure has been developed for producing land cover maps and an associated measure of accuracy. It consists of calibration, resampling, filtering, segmentation, principal component transformation and supervised classification of multitemporal radar images. As input to this processing chain any number of SAR.PRI images or derived texture images can be used. The output consists of a land cover map and an accuracy assessment. The procedure has been applied to a series of 4 SAR images, which yielded a map with an overall accuracy of 78 %. The high precision with which the large banana plantations can be mapped is most interesting, both for its economics importance as for environmental monitoring. By combining this map with the land cover map of 1986 it is possible to detect the changes over the period 1986-1995