Geographic information systems and multiple goal analysis for spatial land use modelling in Indonesia
Method and Techniques
The methodological approach consisted of six main steps: (i) determine physical and economic land
suitability of the area according to the land qualities of land mapping units, and land utilisation types
(LUTs) proposed to satisfy the objectives of stake holders (i.e. farmers, government, commercial.plantation and hydroelectric companies); (ii) define quantitative development goals for specific
development plans according to the projected demands of the local population basic needs, and land
degradation control; (iii) determine goal coefficients for each LUT; (iv) set land use allocation scenarios
according to projected development goals and the goal coefficients of selected LUTs within each LMU
using IMGLP; (v) select the best land use allocation scenarios according to the preferences of decision
makers using AHP; (vi) export the matrices of land use allocation scenario analysis to GIS, and join
them with the digital LMUs for visualising spatial distribution of alternative spatial plans.
This paper focuses on steps (iv), (v), and (vi). Phases (i), (ii), and (iii) are discussed in detail in Suhaedi
and Metternicht (2000)and Suhaedi et al. (2001), and briefly summarised hereafter.
Based on physical data analysis (soil, geology, topography, and aerial photographs) at scale 1:100,000,
field observations, and the geopedologic classification developed by Zinck (1988), twelve physiographic
units were defined as land mapping units (LMUs) and their associated land characteristics were
determined for the entire study area and stored in the digital database via digitising of the polygons’
boundaries (e.g. spatial attributes) and input of aspatial attributes in Dbase IV. These LMUs comprised:
(1) flood plains, (2) alluvio-lacustrine plains, (3) colluvial plains, (4) volcanic plains, (5) alluvio-volcanic
fan, (6) volcanic fans, (7) volcanic foot-slopes, (8) lower volcanic ridges, (9) middle volcanic ridges, (10)
upper volcanic ridges, (11) hills, and (12) mountains. Using the guidelines for physical and socio-economic
suitability developed by FAO (Rossiter, 1994), land suitability analysis was conducted for these
12 LMUs based on seven (7) proposed LUTs (e.g. irrigated rice, rainfed rice, dry land arable farming,
mixed gardens, vegetables, tea plantations, and pine plantations). The results are summarised in Table
1, and the procedure adopted for the analysis is described in Suhaedi and Metternicht (2000).
Setting land use allocation scenarios according to projected development goals
Using a combination of field observations and experts’ opinions, goal coefficients were determined for
the seven proposed LUTs within each of the LMUs as described in Suhaedi et al. (2001). Based on the
projected development goals in the study area, and the goal coefficients resulting from the land suitability
matrix, land use allocation scenarios in the study area were formulated for the year 2004, using IMGLP
equations implemented in the software PcProg (Kalvenlagen, 1986), as follows:
Where: Z
1= maximising food production; Z
2= maximising income availability, Z
3= maximising employment
availability; Z
4= minimising soil erosion; i = the number of LMUs (12 LMUs were determined in the study
area: flood plains, alluvio-lacustrine plains, colluvial plains, volcanic plains, alluvio-volcanic fan, volcanic
fans, volcanic footslopes, lower volcanic ridges, middle volcanic ridges, upper volcanic ridges, hills, and.mountains); j = the number of LUTs (7 LUTs were selected: irrigated rice, rainfed rice, dry land arable
farming, mixed gardens, vegetables, tea plantations, pine plantations); m = the number of LMUs
classified as suitable for a given LUT (S1= highly suitable, S2 = moderately suitable, S3 = marginally
suitable, N= not suitable); and n = the number of LUTs selected and allocated to a given LMU.
Table 1. The Land Suitability Output of Saguling Catchment Area
