In India till recently, initiatives to map different aspects of disasters have been institution specific or related to demonstration of technology for disaster management and mitigation. With the establishment of the National Disaster Management Authority (NDMA) in 2005, several expert committees were appointed to look into specific disasters and issue guidelines. One such working committee of experts (WCE) was constituted to consider the cartographic requirements for disaster management. The aspects under consideration included, understanding spatial patterns of disasters; identifying critical areas, hot spots and multi hazard zones; developing a basis for disaster preparedness, mitigation and management; spatially linking research, analysis and findings; allotting projects for specific purposes and issuing warnings, notices and codes.
Geographical Information System (GIS) enabled maps were to be developed for disaster management which in turn would allow analysis, exposure, awareness, scenario building, codes and identification of impact of multiple hazards. The cartographic base would envelop requirements such as soil, surface ground motion, peak ground acceleration, engineering economy, microzonation, vulnerability analysis, source-site relationship, property analysis, simulation modelling, loss estimation, rescue, mitigation, early warning, and design and masonry codes. Moreover, there are specific requirements for each disaster as well.
Before embarking upon the mapping project, a map availability assessment was made. The NDMA core committee and the WCE on Cartography discussed several possible alternatives. The existing topographical information was considered which included digital elevation models (DEMs) based on Cartosat-1 and 2 data and shuttle radar topography mission (SRTM) data. DEMs for specific hazard prone areas like floods, cyclones and tsunamis were also to be developed. The WCE was of the view that a fresh initiative was required to prepare maps designed specifically for NDMA’s activities. The pros and cons of various technologies such as remote sensing, airborne laser terrain mapper (ALTM), global positioning system (GPS), aerial photography as well as ground survey techniques were debated upon – and a combination of technologies was mandated to be the most viable option.
The NDMA decided to undertake a detailed project report (DPR) through the WCE on Cartography. In the DPR two sets of maps – scale 1:10,00 and 1: 2,000, were to be generated and technological options, mechanisms, financial costs and a time frame for the project were to be evaluated and suggested. The project can be independently taken up by NDMA or a by a central organisation such as Survey of India (SoI), or National Remote Sensing Centre (NRSC). However, the state governments will have a vital role as a lot of relevant information is available only with them.
The terms of reference in the DPR for the mapping at both the scales are:
- To develop a digital and hardcopy cartographic database at 1:10,000 scale at 1 m contour interval. This is to be done in phases, awarding priority to the 241 multi-hazard prone districts in the country;
- To prepare detailed maps at 1:2,000 scale with 0.5 m contour interval for towns and cities falling in seismic zones IV and V or in multi- hazard prone districts;
- To suggest appropriate technologies for under-taking mapping at the proposed scale based on aerial photography or high-resolution remote sensing data, GPS, ground survey or their combination;
- The details of the proposed series are to match with the legend provided in the SoI topographical sheets – roads, rivers, villages, administrative boundaries, contour lines, infrastructure (bridges, power stations, hospitals etc.) and basic land use (water bodies, human settlements, arable land, forests etc.). In addition, the existing mitigation facilities like shelters, helipads, dropping points for relief materials etc. are also to be incorporated;
- In case of the 1:2,000 scale maps, details are to also match with the legend provided in mapping projects of similar scale by the National Informatics Centre, NRSC and Ministry of Urban Development.
NDMA’s mandate is to manage and mitigate disasters in different parts of the country. To assist their activities, the organisation requires maps/spatial data. The WCE on Cartography has initiated the process to address the lack of detailed maps in this sector and before long India will have the requisite atlases for effective disaster management.