LU/LC Development in Semi-arid Tropics: Large-Scale Wasteland Mapping for Sustainable Development - A case study of Achampet Mandal, Mahaboobnagar Dist, AP, India 2. Pilot project 2.1 Study area; achampet mandal, mahaboobnagar district, AP Achampet Mandal lies in Mahaboobnagar district of Andhra Pradesh State. It covers 22 villages, out of which a cluster of 18 villages with an area of 22471.8 hectares have been taken as the study area. The area is covered in Survey of India toposheet (1:50,000) No.56L10, 56L11, 56L14, 56L15. The climate is tropical and temperature ranges from 40oC – 18oC with 1100 mm rainfall distributed over the entire Mandal.  Fused IRS Imagery of Achampet mandal 2.2 Data requirements: The project required a host of data from various sources to be incorporated into the system. As the data sets used were from various sources, adequate attention was paid for data standardization. Sufficient attention has been paid for data format, scale of maps, data quality, authenticity etc., at the time of procurement as well as throughout the execution phase. In this study, three types of data have been used e.g.
Satellite data was procured from National Remote Sensing Agency (NRSA), in digital format. The study area is covered in one full LISS scene, one full PAN scene and three PAN sub-scenes. All these imageries were procured in standard BSQ format for the purpose of digital image processing. The mapping job being carried out at large-scale (1:12,500), LISS & PAN images were procured to generate fused imagery, which ca integrate the spectral resolution and spatial resolution available with LISS & PAN images respectively. Proper enhancement and filtering techniques were also applied to the fused imagery to derive maximum possible details during visual interpretation and mapping. Satellite image mosaic was prepared for Achampet mandal to have a synoptic view of all the villages in the mandal. Hard copy maps were generated out of this fused digital data at 1:12,500 scale (6 plots) for visual interpretation and mapping. The fused images at 5.8-m spatial resolution supported hard copy generation at this scale at 50 microns plotting using fotorite machines(Designed & developed by SSL). Secondary data used for the purpose include:
Ground verification forms an important and integral part of visual interpretation process of remotely sensed data. Ground data is attributed to collection / verification and measurement of information about different surface features, which are responsible for reflectance behavior patterns. It becomes necessary to use ground data in association with remotely sensed data to establish the mapped details with authenticity as well. Ground truth collection is dependent upon the extent of doubtful areas, the sampling procedure adopted during field traverse, terrain conditions, classification accuracy, requirement etc. 2.3 Wasteland Mapping: The methodology essentially involves visual interpretation of IRS ID fused FCC (LISS & PAN) on hard copy for identification of different categories of wasteland using standard image interpretation techniques, based on tone, color, texture, pattern etc., in addition to field based knowledge of the interpreter. Other ancillary data e.g. topographical maps were also used for reference purpose in mapping of wastelands. The interpreted maps were checked on the ground in order to verify the doubtful areas and based on ground verification, the wasteland boundaries are finalized. |