eucalyptus and Casuarina are commonly
planted in these tree plantations. Big-
sized trees of Pterocarpus indicus are
usually growing far apart in the farmlands
of most villages.
3. METHODOLOGY
The main project of this study involved
interdisciplinary team approach in order to
determine the existing situation in the
study area to identify the development
issues, biophysical and socio-economic
conditions, and the relationship between
people and their environment.
The interdisciplinary team work
consisting of three functional groups were
employed, consisting of biophysical and
institution, socio-economic, and
environmental remote sensing and
geoinformation groups. lt is the work of
the environmental remote sensing and
geoinformation group that is being
presented in this paper.
STEPS OF WORK PERFORMED IN
THE STUDY
I. Data Collection
This activity involved the collection of all
the major and ancillary data required to
meet the above stated objectives. Soil
map, hydrological map, reservoir map,
aerial photographs (1983) and land use
map dervied from the landsat TM image
taken in July 1993 and January 1994 were
considered as the major sources of data.
Crops requirements and the limitations of
crops selected were also gathered.
2. Map Preparation
Using the available topographic map of
Lop Buri Province sheet no. 5139 I, dated
1969, base map of the study area were
prepared prior to digitization. Different
coverages of the study area were prepared
separately but each had the same boundary
of the area, following the boundary
611
provided by Kasetsart University. These
coverages included :
(1) the boundary map of the
study area derived from
the topographic map
provided by Kasetsart
University ;
(2) the transportation map,
i.¢. road network in
1983 and in 1993 ;
(3) the drainage patterns
(main stream and its
tributaries, canals or
klongs) ;
(4) reservoir map ;
(5) land use maps in 1983
and 1994 :
(6) slope range map ;
(7) geological map ; and
(8) village location map
The preparation involved some from of
ground reference data. Eight (8) Ground
Control Points (GCPs) were marked on all
maps. For image processing purposes
(with use of CCTs), GCPs are essential for
computing a transformation matrix for use
in rectifying an image (ERDAS Field
Guide 1991). The GCP values were
converted into Universal Transverse
Mercator (UTM) values for the purpose of
digitization.
3. The Global Positioning System
(GPS)
Global Positioning System (GPS) is a
satellite based navigation and positioning
system that can accurately georeference
and type of spatial information in almost
any place of the earth. GPS is able to
provide map coordinates of either
latitude/longitude or the Universal
Transvers Mercator (UTM), the elevation
of the observation point, the time when
the record was taken, the prescribed zone
value of the point location and others.
using
4. Basemap Preparation
ARC/INFO-GIS
International Archives of Photogrammetry and Remote Sensing. Vol. XXXI, Part B4. Vienna 1996