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Education and curriculum development in Photogrammetry in India
Principle of Photogrammetry
Photogrammetry is mainly known for its stereo-scopic model for determination of height. The 3-dimensional view of a photographed object kindled the imagination of various scientists, which has led this field to extent of virtual reality - 3D animation. A 3-dimensional model gives a better way of understanding about the nature of the object rather when it is shown as elevation, top view or section. A very common man can also be able to appreciate the usefulness and for assessment. The basic principle of photogrammetry is our normal human eye - our vision. We can be able to feel the height difference of one object relative to the other, if we see with our two eyes. With one eye we may not be able to feel the height difference. Stereo scopic vision of Photogrammetry has its principle here. If we would be able to see one object from two different positions (left eye and right eye) we can get the stereo (3D) view. So if a same object is photographed from two different positions relative to our eyes, we will be able to get the 3D picture of the object. i.e., depth perception is achieved. This forms the basic principle in photogrammetry. To view the same object from two different positions aerial photos from airplanes are taken with regular overlap successively to have a seamless stereo view of the entire area. These overlapping photographs if could be kept in the same orientation as at the time of photography the 3D view of the object is created. The 3D model thus created should then be used for taking measurements which is the main objective of photogrammetry. For taking a measurement, the 3D model need to have some reference to start with. To refer the model to some co-ordinate system, for taking exact measurements as it is in the ground reality, control points, normally referred as ground control points are collected. After having oriented the 3D model to the ground reality, any measurements taken thereafter are as same as it is taken in the ground. To perform all these operations the photogrammetric process called interior, Relative and absolute orientation were preformed.  Aerial Photography The stereo captured maps created only can have the accurately interpreted and captured features only. As such it don't have information of the nature of terrain. Whether it is of steep slope, gradual slope, highly undulated terrain, hills / valley.... Nothing will be able to get from that. To represent the terrain, Digital Elevation Model (DEM) which is a continuous representation of the change in the elevation of the terrain and the contour (lines joining equal elevations) can be generated. For the people who may be interested in working with the monoscopic images for mapping, ortho photographs (having uniform scale, free of normal errors of photography) are useful. With these products of photogrammetry, mapping of any area to the actual size, shape and position will come to reality. Photogrammetry in India National Remote Sensing Agency in India, is the authorized agency for carried out the aerial photography for commercial users of various government and private agencies. Aerial photography was also carried out mostly in the past for disaster management like flood, earth quake, landslide, forest fire, coal field monitoring etc., Various types of sensors like black and white, colour, infra red, multispectral scanner are been employed for aerial photography in India. Because of the highly restricted nature of aerial photography, the use of photogrammetric techniques was confined to a smaller circle. This was originally practiced by Survey of India, National Remote Sensing Agency and other state Remote Sensing Agencies. Aerial Photography can be had by any government or private companies after getting the clearance from ministry of defence. Potential for Photogrammetry Due to the invention of computers the era of analog photogrammetry systems (fully manual) took a change towards analytical systems, where most of the computations were performed automatically through use of computers. Due to further advancements in the field of computers, new techniques of object and pattern recognition, high-speed processors, large storage disk space etc., digital photogrammetry has come to existence. Because of the various advantages and speed of processing of data in digital environment with a very low cost, digital photogrammetry has got a good potential in the world market. Aerial Photography and the outputs of Photogrammetry can be used for town planning, utility mapping, tax assessment, flood mapping, forest fire mapping and monitoring, mining, Earth Quake / volcanic damage assessment etc. The police can use these technology for crime analysis and riot management. Highway planning, Railway alignment, pipeline survey, Irrigation canal alignment and management, New layout designing, 3D City modeling, power line monitoring are few other application areas. Close Range photogrammetry, a branch of photogrammetry is nowadays been used extensively in the field of medicine, various industries etc., The permanent stereo record of the existing monuments and archeological importance structures can be made with photogrammetric techniques. In India many municipal and metropolitan authorities of various town and cities are in need of large scale accurate mapping for the infrastructure development and planning activities. Bangalore Development Authority, Hyderabad Metropolitan Water Supply and Sewerage Board, Rajasthan Urban Infrastructure and Development Programme etc, TCPO under MoUD., had already started using these technologies to create large scale maps for use in Geographic Information System (GIS). Private participation in the field of digital photogrammetry also are increased. So many companies like Infotech Enterprises Ltd. - Hyderabad, DSM soft (P) Ltd. - Chennai, Kampsax India (P) Ltd. - Delhi, Rolta India, Mumbai, Speck Systems Hyderabad, Genesis of Bangalore, IIC technologies of Hyderabad and so many other companies are practicing digital photogrammetry in India. As of now the job potential in these industries are more for trained and skilled Photogrammetry operators and managers. In a recent study made, it was felt that the potential for large scale mapping and GIS activities are about 55,000 crore for India. Such an huge untapped market is present in India. Photogrammetry education in India Though, potential market for Photogrammetry exists in India, the formal education in the field of Photogrammetry is very less. There are very limited numbers of institutes which offer Photogrammetry course. Institute of Remote Sensing, Anna University has a unique four-year bachelor program (Geo - Informatics) and a M.Tech Program in Remote Sensing which gives main emphasis on photogrammetry and Remote sensing. University of Roorkee, currently given the IIT status is also having very good curriculum for photogrammetry for its M.Tech program. Apart, IIT Kanpur, Chennai, Mumbai also provides Master degree in Remote Sensing and GIS. Apart from these few other universities and colleges like JNTU, Hyderabad, BITS also provide Master’s degree course on Remote Sensing and Photogrammetry. In India, the Survey of India has its own "Survey Training Institute" (STI) - Hyderabad, which imparts training in photogrammetry. National Remote Sensing Agency (NRSA) also gives training in Photogrammetry, Remote Sensing and Geographic Information System (GIS) in its main campus in Hyderabad and in Indian Institute of Remote Sensing (IIRS) - Dehradun. Apart from this Institute of Remote Sensing, Anna University - Chennai is also conducting training programs in photogrammetry. Other than these government agencies many other private companies are also giving training on the basic theories and operation of various commercial digital photogrammetric systems. We need to accept that the state of art facilities in the field of Photogrammetry is largely absent in many of the institutes. Availability of trained and highly skilled staff in teaching the fundamentals of Photogrammetry is very less. Many of the private training institutes except a few, wants to cash on the potential market. So the fresh graduates from various disciplines are trained on commercially available digital Photogrammetry software for stereo perception and were certified for acquiring the Photogrammetry training on principles and concepts. Even though, the candidates were able to perform their jobs in private companies, they were not able to go forward in their career after a certain limit due to lack of technical competencies. This has created a wide gap in the Photogrammetry industry. It is a fact that many industries are still in look out of potential candidate to head their divisions independently. It is a fact that many of the GIS and RS professionals are not aware of the concept of scale and its related accuracy factor in terms of information content and positional accuracy content. Because of the availability of cheap and skilled manpower, Indian companies are able to get more projects. But the companies also should realize that apart from just a 3D data conversion companies, they should get transformed into the complete solution providers in this area. So they also need to encourage the staff and provide guidelines for their staff in identifying the quality institutes offering Photogrammetry education. |