The importance of the PMGSY stems from the fact that rural roads play an important role in the economic development of our country where a large percentage of people still live in rural areas and are heavily dependent on agriculture. Rural roads enable people to have access to basic economic and social services, and also to transport agricu ltural produce to the market centres.
The project to use GIS for the PMGSY in Gujarat is being carried out by Vadodara based CAD Consultants & Services (CCS). An important part of the PMGSY is the preparation of detailed District Rural Roads Plans (DRRP) and the Core Network (CN) Plans. The District Rural Roads Plan for a district contains detailed information on the existing road network system for all the blocks or talukas in the district which includes national highways (NH), state highways (SH), main district roads (MDR), other district road s (ODR) and rural roads constructed by different agencies, the roads under construction as well as cart tracks and paths. The DRRP also clearly identifies the proposed roads for providing connectivity to unconnected habitations in an economical and efficient way, in terms of cost and their utility. The Core Network Plan is the network of all the rural roads that are necessary to provide basic access to all the habitations. A Core Network Plan is extracted out of the total network of the DRRP, and consists of existing roads as well as the new roads required to be constructed for the as yet unconnected habitations. This entire process generates a large amount of information related to rural roads such as number of habitations in a block, number of blocks in a district, the population of the habitations, block boundary, district boundary, DRRP Roads, CN Roads, CN Road Segments, road surface type, bridges, level crossings (manned & unmanned), stone and sand quarries, market centres, water bodies, tourists places, drainage, railway lines and much more. This volume of information is difficult to process, manage, update, sort and retrieve by traditional, manual methods. A GIS database is quite suitable for planning, constructing and monitoring of rural roads since all the relevant data in this case is geographically referenced, and the GIS makes it very easy to store, retrieve, analyse and present geographically referenced data.
Geo-referencing of data: After the preparation of the digitised maps the spatial data was Geo-referenced, a process by which features on the maps are assigned real-world coordinates. This process is done through the OMMS software mentioned earlier. Now the two types of data – spatial and non-spatial or attribute data have to be linked so that the total number of spatial features represented in the maps match the corresponding data. This linking was done through special GIS software. At this stage, spatial features in the maps were cleaned and fine-tuned. The data was carefully checked for completeness and accuracy as this decides the usefulness of the data for actual, real-world use. Lastly, the GIS database underwent the process of topology creation, a process which helps in analysing the roads in the maps, developing relations among them, and their spatial relation with other map features. The checked GIS database was now ready for analysis and its ability to respond to different queries which would help in decision-making, monitoring and maintenance.
The GIS maps thus finally prepared can be opened in Google Maps, Google Earth and ISRO’s Bhuvan without any external software. This makes it very convenient for the concerned officials of the PMGSY and other government officials to check any relevant data and monitor the construction of roads, etc., online from any convenient location.
A GIS based database thus prepared with digitised DRRP and Core Network Plans is very useful due to its high accuracy, and ease of retrieval of data. Thakore adds, “The information about sand and stone quarries in the DRRP maps is useful for both the government and contractors. The government plans the construction of roads, and floats tenders taking into account the location of these quarries, sand and stone being chief raw materials in road construction. It also pays the relevant contractors on the basis of the certified and documented distance of the quarries from the place of the road construction. Though the information about elevation of the habitations from sea level in the GIS database and about the exact geographic location of habitations is useful in many ways apart from the road use, the information about cross drainage in the map gives an idea of the various sources of water that cross or will cross a road along its whole length – streams, rivers, lakes and other water sources. Depending on this information, a decision is taken to construct bridges at the relevant places, or perhaps change the alignment of the road if construction of a bridge is not possible due to economic or other reasons.”
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