Rajan, KS
A GIS BASED INTEGRATED LAND USE/COVER CHANGE MODEL
TO STUDY HUMAN-LAND INTERACTIONS
K S RAJAN* and Ryosuke SHIBASAKI**
*Institute of Industrial Science, University of Tokyo, Japan
** Center for Spatial Information Science, University of Tokyo, Japan
shiba@skl.iis.u-tokyo.ac.ip
KEY WORDS: Land Use/Land Cover, Modelling, GIS, Global Change, Biosphere
ABSTRACT
Land use and Land cover form an integral part of all modelling initiatives in case of global change studies and hence,
there arises a need for time-series data of land use/cover. As such, we need suitable models to explain the changes in the
land use patterns and the resulting land cover and also to forecast them. The model proposed here deals with the
development and application of a new concept in simulating the land use/cover changes — the presence of an “agent” as
the autonomous decision-maker. The biophysical characteristics of the specific lot of land (grid) and its economic
potential (based on the macro-economic information) are considered within the existing demographic conditions at a
given point in time, in arriving at the choice of the land use. The changes are simulated annually and the entire process
is carried out on a grid (Ikm square) basis. The use of GIS platform and its tools has helped in analysing the micro-
information (spatial) within the boundaries of the available macro-level (non-spatial) data. The model was developed
and its application was tested to simulate the land use changes, for the period of 1980 to 1990, within the national
boundaries of the Royal Kingdom of Thailand. As the model considers the agent behaviour explicitly and at the same
time considers the different drivers to landuse, the model can also be used to understand the human responses to the
changes in the environment.
1 INTRODUCTION
The spatial and temporal distribution of land use and land cover is very important in understanding a wide variety of
global change phenomenon. Data from remote sensing helps us to monitor such changes but future estimates of change
are hard to tell. As such, it is necessary to have reliable information on the land use/cover and an understanding of the
changes that occur within them. So, there arises a need for time-series data of land use/cover. As such, we need suitable
models to explain the changes in the land use patterns and the resulting land cover and also to forecast them. In
modeling land use/cover changes realistically, we need to consider the scale of analysis of such changes, as some
changes at a particular scale may act as drivers at a different scale. It is recognized that changes in the scale of analysis,
changes the results (Alcamo et al., 1994, Robinson, 1994). The model should be able to simulate land use/cover changes
in response to changes in both the biophysical characteristics and socio-economic conditions. At present, the global
models and studies of land use changes capture the broad sectoral trends based on the changes in some of the macro
variables, like population, quality of life and technology level. The statistical data shows a strong support in concluding
that these variables may be the underlying drivers of environmental changes (Bilsborrow et al., 1992). Nevertheless,
studies at the local level suggest the existence of other factors too, such as the farmers’ preferences to certain crops and
changes in land use driven by migrations within the national boundaries (Fukui, 1993).
The transformations in the land cover, occurring on the large scale will lead to large-scale changes in the "global
environment”. These changes are complex and require different scales of analysis. It is good to start at the national scale,
as the assumption of uniformity in modelling approach within the national boundaries, does not lead to erroneous
conditions vis-à-vis the various variables/parameters used in such a model. Also, in order to get a complete picture of
the land use changes, we need to account for the drivers based on both the micro-characteristics and the macro-
economic scenario that exists.
The model proposed here deals with the development and application of a new concept in simulating the land use/cover
changes — the presence of an “agent” as the decision-maker. The decision-making process of the agent is autonomous in
deciding the next course of action based on the information available to him, from both the worlds of micro and macro-
information, at a particular point in time and space. The biophysical characteristics of the specific lot of land (grid) and
its economic potential (based on the macro-economic information) are considered within the existing demographic
conditions at a given point in time, in arriving at the choice of the land use. The changes are simulated annually and the
entire process is carried out on a grid (1km square) basis and is aggregated at the different scales — from the local grid to
1212 International Archives of Photogrammetry and Remote Sensing. Vol. XXXIII, Part B7. Amsterdam 2000.
