Development of a GIS based application for selection of villages for sodic land reclamation
Data processing / analysis
Sodic land map: Sodic land map of the study area was implemented in GIS. This layer consists only barren sodic lands mapped from Satellite data in 1987. All the polygons of sodic land were assigned single class. The sodic land map was integrated with Village boundary map through union. From the resultant map, village wise sodic land area was computed. Based on percent of sodic area to the geographic area each village was assigned a rank. Final sodic suitability layer was prepared by product of rank and multiplication factor for each village. The resultant map (fig. 2) shows all the villages classified in four categories as per their suitability for reclamation. Villages having more than 30% of sodic area are 128, 25-30% are 149, 15-25% are 234 and rest are not suitable (table 2). Drainage map: From the Drainage layer, buffer zones were generated at a distance of 500 m, 1000 m and 2000 m from each drain. The village boundary layer was integrated with buffer layer through union. The village boundaries intersecting 2000 m buffer were assigned rank 3 and rest of villages were assigned rank 4. Within rank 3 villages, those intersecting 1000 m buffer were assigned rank 2 and within rank 2 villages those intersecting 500 m buffer were assigned rank 1. The final drainage proximity layer (fig.3) was prepared by calculating product of rank and multiplication factor for each village. Based on the analysis criteria 1112 villages are falling in rank1, 212 in rank2, 228 in rank3 and the rest in rank4 (table 2).  Depth to Groundwater: The depth to groundwater contour map has been classified into four groundwater zones as per the criteria mentioned in table 1. Integrated groundwater layer with village boundary layer through union. Village wise statistics were computed and suitable rank value was assigned to each village based on maximum area falling in one of 4 groundwater zones. The final groundwater suitability map was prepared by calculating the product of rank and multiplication factor. The resultant map shows total 1190 villages falling in rank1, 286 in rank2, 129 in rank3 and rest in rank4. |