,lth. Spaec ~ Vol.2, No.8, pp.137—145, 1983 0273—1177/83/080137-09$04.50/O Printed in Great Britain. All rights reserved. Copyright © CUSPAR A HOLISTIC APPROACH TO THE MONITORING OF LAND COVER CHANGES IN SRI LANKA USING INTERMEDIATE REMOTE SENSING TECHNIQUES U. Geiser*, M. Sommer*, H. Haefner** and K. I. Itten** *Survey Department, Center for Retnote Sensing, Colombo, Sri Lanka * *Departmenl of Geography, University of Zurich, Switzerland ABSTRACT Heavy social and economic pressure on the available land resources in Sri Lanka are causing major land-cover changes. They need to be assessed to serve as input data for decision-making processes e.g. in agricultural or ecological planning. The Sri Lanka/Swiss Satellite Imagery Interpretation Project has developed a holistic approacn to the mapping and monitoring of the land-use and the land-cover changes. The method applies intermediate level technology and is based on a benchmark/masking technique using satellite images, aerial photography and field surveys. The regular monitoring of changes of land-use types as a whole, e.g. forests, is part of the approach as well as the periodic assessment of changes within a specific land category, e.g. the seasonally cultivated riceland. The activities have to be transferred from the level of scientific research to the actual application within a reasonable time frame using the local resources. Discussed are also some of the problems inherent in the implementation of remote sensing activities in a so- called Third World country. INTRODUCTION Heavy social and economic pressures on the available land resources in Sri Lanka are causing major land-cover changes. No information on these changes nor a concept or the techniques for its monitoring were available. Therefore the Sri Lankan Authorities requested the Swiss Government for technical assistance in research, development, implementation and application of satellite remote sensing techniques that could provide the country with these urgently needed basic data for agricultural and/or ecological planning and resources management. The Swiss Government has charged the Remote Sensing Section of the Department of Geography, University of Zurich to setting up such a program. In a pilot phase satellite techniques were tested for rice—yield forecasting, since paddy cultivation plays a key role in the countrys agriculture. The declared aim is to reach self-sufficiency in the rice production. Conse- quently immense efforts are undertaken to increase the productivity on the existing land and to extent the cultivated land. The latter procedure puts great pressure on the available land resources, mainly forests in the less densly populated parts of the country — e.g. the north-eastern part of the island. This triggered substantial land—cover changes. From this test phase (GEISER,SOIV~1ER, NANAYAKKARA, 1981) it became quite obvious that the overall changes in land—cover from the past decade have reached a level that calls for an immediate and continuous surveying and monitoring of the total country. APPROACH To achieve this goal and to install a lonyterm program which will be carried out and main- tained later on the countries own efforts and responsibility the Sri Lanka/Swiss Satellite Imagery Interpretation Project was established to accomplish the following activities: - Establishment of a Center for Remote Sensing (CRS) at the Sri Lanka Survey Department - Training of personnel in appropriate analog remote sensing techniques (intermediate level technology) 137