IAPRS & SIS, Vol.34, Part 7, “Resource and Environmental Monitoring”. Hyderabad, India,2002 
   
  
   
   
    
  
   
    
   
  
   
    
   
      
   
   
    
    
    
    
   
  
  
  
    
   
   
   
   
   
   
   
     
Spatial model development in a GIS context 
involves the use of integrated geographic 
database within the frame work of an 
application and then applying suitable criteria 
for analysis. Criteria for analysis can divided 
into two categories, namely, statement criteria 
and table criteria. In statement criteria, 
relationship of parameters is defined as a 
statement. The table criteria approach lays 
down all possible combinations of relationships 
and thus provides a total solution from the 
dataset (Nema et aL, 1999). In the present 
analysis, a table criteria approach has been 
adopted. The weights (acronym Wt.) adopted 
for different classes of all thematic maps along 
with their area are shown in Table 1. 
  
  
  
  
  
Thematic Classes Wt. Area 
Maps (km?) 
Slope Gentle 8 365.49 
Mild S 64.74 
Medium 3 72.76 
Moderate 1 1.45 
Soil Sandy loam 7 13.33 
Loam 6 191.58 
Silt loam 4 195.41 |. 
Silty Clay 3 49.24 
Silt loam- 1 54.83 
(Strongly 
Alkaline) 
Ground Very Good 4 428.80 
Water Good 3 21.86 
Potential Medium 2 43.23 
Low 1 10.55 
Rainfall Medium 2 504.44 
  
  
  
  
  
  
Table 1. Criteria Table 
6. LAND SUITABILITY CLASSES 
After overlaying and performing union of soil 
map, slope map, rainfall map and ground water 
potential map, Land Suitability Index (LST) has 
been computed by using the table criteria 
approach. The integrated map shows 410 
polygons having different LS/ values which 
were suitably merged into five different classes 
by using computer programme developed in 
Arc Macro Language (AML) of ARC/INFO 
GIS. These suitability classes are: (1) Class I 
(Highly suitable for agriculture), (11i) Class II 
(Suitable for agriculture), (iii) Class III 
(Moderately suitable for agriculture), (iv) Class 
IV (Suitable with restrictions) and (v) Class V 
(Not Suitable for agriculture). 
The final land suitability map has been shown 
in Figure 5, while the area of each suitability 
class has been compiled in Table 2. 
  
  
  
  
  
  
S. No. Class Area Area 
(km) | (%) 
1 Class I 149.06 | 29.55 
2 Class II 120.34 | 23.86 
3 Class III 71.05 | 14.08 
4 ClassIV..| 162.839 | 32.29 
5 Class V 1.1 0.22 
  
  
  
  
  
  
Table 2. Land Suitability Classes 
From land suitability map, it may be observed 
that nearly 30% of the study area falls under the 
category of highly suitable land for agriculture 
while about 28% is in the suitable class. Nearly 
32% of the area is covered by the land suitable 
with restriction. This is the area which falls 
mainly in the Phulpur block where the soil is 
strongly alkaline silt loam; and in the 
Bahadurpur block where the slope is moderate. 
Suitable remedial measures may be taken for 
these areas. The areas which fall in Class IV 
and V may be used for developmental works 
other than agriculture like residential projects. 
7. CONCLUSIONS DRAWN 
In the present work, a GIS based spatial model 
has been developed for land suitability analysis 
for a part of Allahabad district; and five land 
suitability classes, namely, highly suitable for 
agriculture, suitable for agriculture, moderately 
suitable for agriculture, suitable with 
restrictions and not suitable for agriculture are 
obtained. The highly suitable land constitutes 
about: 30% of the total area and improved/ 
modern farming practices may be adopted to