Rear Admiral K. R. Srinivasan
AVSM, Chief Hydrographer to the Govt. of India
- Coastal Zones today are the hubb of maximum human activity. Maximum development in terms of new ports, open wharfage, power plants, marine trades, oil installation, aqua farming etc. is taking place along the coast. The unplanned industrialisation is disturbing the ecological balance. The population along the coastal areas is sharply increasing. It is estimated that by the year 2005, 50% of the world population would be living in the cities and 50% of that along the coastal cities. In view of population growth and diminishing natural resources, the economic growth is required to be planned in judicious manner in balance with resource conservation and Environment Management. Coastal areas are already experiencing ecological pressers due expanding tourism, high population densities and rapid industrialization. Excessive exploitation of resources will make communities vulnerable to sea storms and other Ecological disasters. Therefore coastal zone require proactive planning to manage them.
- A map is the first tool for management. Survey of India maps on scale of 1:25,000 based on topo sheet on scale of 1:50,000 are available, while this may be adequate for CRZ planning, it is not adequate for large scale maps of scales larger than 1:25,000, specially required in Urban areas and coastal cities. CRZ maps showing wetland features between HTL & LTL and land use features upto 500 mtrs. from HTL on scale of 1: 25,000 scale for the entire Indian coast have been prepared using IRS LISS II and SPOT data. However, the planimatric accuracy of these maps can be used only for macro level planning and not for town planning and for specific projects. The navigation charts covering the entire Indian coast have been prepared by Naval Hydrographic Department on varying scales. The scales for harbour charts being 1:25,000 and on other bathymetric charts on a scale of 1:1,50,000 scales. Aerial photographs on scale of 1:50,000 and 1:25,000 for the entire India are also available. Cadastral level maps on scale of 1:3960 prepared by state authorities are also available. However, these datas are of different vintage, for example the source data for Survey of India topo-sheet is of 1970 to 1980 period, the data collected by National Hydrographic Office is of 1994 to 1995 period and the data collected through satellite is of 1996 period. The data from various sources is collected on different projections and different datums. There are cartographic problems in matching the large-scale cadastral maps prepared using different sources and at times the distortions upto 300 mtrs have been experienced. This type of distortions is not suitable for town planning. The different source data used by different states will create its own complications in adjoining areas. The problem is further complicated where the authorities authorized to prepare town maps in various states have different training background, expertise and experience varying from coastal state to state. Therefore, there is an urgent need that CRZ issues to be taken as National programme with all mapping agencies using same methodologies, same datum, same projection and with similar interpretation, so that, uniform rules are followed in all the states and adjoining areas of states get depicted uniformly in accordance with CRZ regulations. For the purpose of uniform training and understanding, the Naval Hydrographic Department has submitted proposal for a National Programme and for imparting training to field surveyors and land marking authorities. This proposal, once implemented will ensure that the field surveyors and land authorities all over the country will adopt the same yardsticks and accuracies and there by reduce many litigations, being currently forced by user agencies based on ill-advised cartographic principles like enlargement of small scale maps beyond certain limits. Adoption of conversion parameters will help in deriving the type of ground accuracies expected in a CRZ maps of today and tomorrow.
- Way ahead in concurrence with cartographic principles:
- Use SOI topo-sheetes upto 1:25,000 and cadastral maps.
- Arial photos + satellite data to be duly geo-referenced with Datum Conversion Parameters/ground control points cartographically adjusted keeping in view the accuracy requirement for planning purposes.
- Large scale maps, larger than 1:25,000 to be prepared using ground techniques.
- ALTM using laser systems by digital data collection as it will enable plotting on any scale, to be taken up as a National Project.