§Geological surprises
Especially in the Himalayan region where the water resource potential is high by means of glaciers and intensive rainfall updating of the information is required frequently, which is time consuming by conventional method.
Most of the power projects in these regions demands for underground tunneling which is most difficult and expensive affair.
Present means to conduct survey using remote sensing, aerial survey, and GPS based survey have certain limitations
- The topological maps used for walkover survey and preliminary can be very old and recent changes in inhabitation pattern, vegetation coverage and water bodies etc. are not updated frequently.
- The surveying staff does not have bird's eye view of the present ground condition, which may result in large inaccuracies in estimation of civil works.
- There is every possibility of error in recording the ground data and subsequent transfer on the route map.
- Expensive: Require lot of expertise, specialized equipment and time consuming.
The conventional method of assessing hydro potential could not be directly adopted in the inaccessible areas like Himalayas where the water resource potential is high by means of glaciers and intensive rainfall. Similarly the geological, structural configuration is essential to study and to understand the strength and weakness of the area so that the project will be implemented in the suitable terrain. For geologic mapping, reflectance information of the rocks is very important.
Study of alternative ranking and taking optimal decision require lot of time in co-ordination of data (topology, hydrology, geology, geographic, meteorology and environment etc.) from various departments and preparation of maps of updated informations. These factors are great deterrants to faster implementation of hydropower projects.
In the proposed methodology the satellite images obtained from IRS-IB/1D is used to develop GIS database for, identification of source, selection of site, environmental planning, digital terrain model data (DTM), transmission line network and ranking of the sites. A rule-based expert system is developed on Prolog platform for decision support at each stage of modeling.
Development of GIS in Knowledge-Base environment:
Geographic Information System (GIS) is a computer based information system used to digitally represent and analyze the geographic features present on the Earth surface and the events that are taking place. It is not restricted to the conventional view of geography, i.e. that of people and places on the Earth's surface, but GIS is the perfect tool to discover hidden geographies, to explore the hidden facts of World Wide Web, the complex geography of a printed circuit, the architecture of a combat aircraft, or layout of high-tension transmission lines.
The planning for the Hydel Power generation can be accomplished in the following steps.
1: Remote sensing and Image processing:
Remote sensing technique has witnessed a wide range of application in natural resources database management in recent years. In satellite-based remote sensing data collected by satellites are processed by digital computer or optical techniques to extract valuable informations for scientists and engineers. One of the most widely used data format for information extraction is the infrared False Color Composite (FCC) image. The extraction of information from such images about ground reality is done by image interpretation for which generally three methods namely photo interpretation, spectral analysis and data integration are used. In this paper our concern is with photo interpretation method and the development of a rule based expert system for image interpretation of the region and planning Hydel Power Generation. Photo interpretation is the visual interpretation of images based on features like tone, pattern, shape, size, shadow, texture and association. Most of the conventional digital images processing techniques are based on color or size or texture or tonal variation of each pixel in the image.
In contrast to digital analysis of the images, a human interpretater exploits the aggregate information related to various basic image-features of unknown object along with his scientific knowledge, general knowledge of the phenomena as well as experience of doing classification rather than analysing the image pixel by pixel. As a consequence, the interpretation result for land use and land cover produced by a well-trained human interpreter is often less crude than the same obtained using digital techniques. For human interpreter it is easy to interpret natural color image but the interpretation of FCC image becomes difficult and requires adequate training and experience. Also different band combinations of satellite data for three primary colors result in different FCC images, which are suitable for different application. Every application of remote sensing deals with a specific subject or integrated process of different subjects. Thus the process of visual interpretation of wide variety of remotely sensed data is a complex intuitive process of combining evidential information from different sources and subjecting such information to an expert's knowledge, experience and heuristics at each levels namely detection, identification, analysis, recognition and classification of the process. It calls for the analysis of a number of related information by a domain expert. So even with on- going advances in digital image processing technique the importance and role of human photo interpreter can not be ignored and it is required to train human resources to gain this skills .In future the scope of on-screen interpretation of high resolution remote sensing data will increase and image identification system providing way to combine together human interpreter and machine interpretation accuracy achieved using digital image processing technique has been reported up to 70% to 80%. The associated information and logical reasoning that are used by a well-trained human interpreter can be encoded in the form of rules and facts to create knowledge-based systems. The activity of image interpretation has similarity with the nature of explorative and qualitative reasoning in the line of Artificial Intelligence (AI) and expert system. Since the interpretation of each FCC images requires different skill and experience and thus even for a human interpreter it becomes difficult to manage properly application of huge knowledge while making decision in photo interpretation. Also the human interpreter may be absent or not easily available. The knowledge used in photo interpretation can be represented in logical paradigm that makes the logical programming language like Prolog highly suitable for expert development.