T. Toivonen

In the present paper a mosaic of 130 Landsat TM satellite images is used to identify navigable rives in the Western Amazon region and to analyse the accessibility pattern of the area via the river network. The environmental heterogeneity of the Western Amazonia is enormous, and thus the potential for human use varies significantly. In sustainable land use planning accessibility of potential resources is of paramount importance. Most studies and zoning proposals neglect the issue of accessibility or ignore the river network. Our study concentrated on the accessibility in the Western Amazonian region shared by several countries. A Landsat TM mosaic was created over this area and waters were separated by rationing of TM bands 5 and TM, classification and manual corrections. With the 100-meter resolution used, navigable rivers could still be delineated. Grid-based model on the on the accessibility of peripheral areas around regional, provincial and local centres was created and the accessibility pattern of the entire region and within each country was analysed. Nearly entire Peruvian Amazon as well as the vicinities of the main course of the Amazon River were found the most accessible regions, whereas large parts of Colombian and Brazilian Amazon were poorly accessible.

SUMMARY Research, development and education throughout Europe suffer from the poor availability and pricing policy of spatial data. The Finnish National Geographic Information Strategy 2005 - 2010 identifies a new service type that fits together the needs and requirements of both data producers and users. The approach of the 'Spatial Data Lending Facility' is new: a library of data sets

An analysis of tropical rain forest covering Amazonian lowlands has highlighted a systematic across-path, east–west radiometric gradient within Landsat TM imagery. Visual assessment of 45 and quantitative analysis of 20 Amazonian Landsat-4 and -5 TM scenes show that the gradient is band dependent and pronounced in visible light bands 1 to 3 but significant also in IR bands 4 to