GIS-based Census gets under way in India

GIS-based Census gets under way in India


India: The exercise for Census 2011 has got under way in India this month. In the first phase, the housing and house listing operation will be completed which will be followed by census enumeration in March 2011. GIS is poised to play a significant role in the Census, taking further its role in the previous Census.

One of the important achievements of 2001 Census was to generate the digital geographic database of villages, showing the boundary for each sub-district in the country for use in GIS except for some states where the land settlement survey has not been taken up or completed yet.

According to Dr. A P Singh, Deputy Registrar General (Map), Office of Registrar General of India (ORGI), one of the most important pre-requisites of any census is the availability of latest maps for use in census. In order to have a complete enumeration of the entire country without any omission or overlapping, it is important to have a complete coverage of the latest administrative set-up like states, union territories, districts, sub-districts, villages, towns and towns-in-ward which are  cartographically represented in the form of maps. The quality of maps used in the census influences the quality and reliability of census data.

After 2001 Census, several jurisdictional changes had taken place at district, sub-district, village, town and ward-in-town levels. As part of preparations for Census activities, all such changes that have taken place after the 2001 Census are incorporated on the maps at state, union territory, district and sub-district level to have a complete and updated map of the respective areas. These changes are also tallied with the list procured from concerned authorities in state and union territories.

Singh informs that it has become quite easy to update these digital maps showing the jurisdictional changes as occurring between villages or at higher administrative levels. Cartographic representation of new state, district or sub-district has become easier now with the advent of computer-assisted cartography.

In case of maps of towns other then capital cities, however, there is a huge gap in terms of up-to-date information. The Census organisation has already completed the task of procuring town maps showing the extent of town and ward boundaries within these towns. The information from government notifications on the outer limit or extent of the town and division into wards has been incorporated into respective town maps and then digitised for use in GIS. However, the information on complete layout of buildings and other housing structures, lanes, by-lanes and important landmarks are still not available either on paper or on digital format for use in pre-census mapping activity.

To address this problem, the organisation has recently taken-up the task of preparing digital geographic database of each ward showing complete layout of buildings and other housing structures, lanes, by-lanes and important landmarks  for use in delineating census enumeration block (CEB). In view of the large volume of the work involved and time constraint, 33 capital cities/towns have been taken up initially. During field surveys, the information such as house number, number of floors, purpose of use, type of house and approximate population living in the house is being collected. The final digitised database of geographic entities, properly geo-referenced ward map is being used to delineate CEBs.

According to Dr. Singh, at the post census stage, the digital geographical database of administrative boundaries would be extensively used for disseminating Census results in print format, on CDs as well as on the web site like the earlier Census. Various applications for dissemination on CDs as well as for the use on the web using the maps would be developed for disseminating census results. Besides, printed atlases on administrative boundaries at state, district and sub-district levels would be brought out to serve as reference material for planning, user agencies and other research organisations.    

Singh adds that Census mapping ensures that enumerators can easily identify their assigned set of area. Maps are also issued to census supervisors to support planning and control tasks. Maps can thus play a role in monitoring and identifying problem areas and implementing remedial action quickly.

Cartographic presentation of Census results provides a powerful means for visualising the results of a census. This supports the identification of local patterns of important demographic and social indicators. Singh informs that the Census organisation has digital files of all the villages in India. ORGI proposes to geo -reference all of them to link the census data and bring a dynamic information system. So far, the organisation has been producing thematic maps but is envisaging offering a GIS-based decision support system (DSS) by bringing spatial and non spatial data together. It proposes to generate interactive thematic maps in the GIS domain for the user departments, planners, researchers, students and policy makers.
Source: By Our Correspondent