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Geographical Information System For Planning And Management Of Rural Roads
The paper base map was scanned and registered with pre-marked control points showing longitude and latitude to convert it into GIS environment. From the scanned image, six different layers viz. boundary as area layer, road, water bodies and railway lines as line layers and location of habitations and cross drainage structures as point layers were extracted. While digitizing the different layers a unique identification number has been provided to the habitations in the point layer as well as to the roads in the line layer, as given in the attribute data tables to make the spatial information database compatible to the map data within the GIS software. This labeling is essential for further analysis and referencing. The digital base map thus prepared with all the features and important labeling of the spatial information for a typical block is shown in Figure 1.
 Figure 1 Typical GIS Base Map for DRRP Core Network Preparation Core network is essentially a network that provides basic access to all habitations of qualifying population with all-weather road connectivity (MORD, 2002). The core network consists of through routes and link routes. Through routes are the ones which collect traffic from several link roads serving a long chain of villages and lead to market centres either directly or through the higher category road such as a National Highway, State Highway or a Major District Road (MDR). Link routes are the roads connecting a single habitation or a group of habitations to through routes or a major link road leading to the market centre directly. Using the network and routing modules in GIS environment, the task of preparation of the core network can be simplified. The core network thus identified can be prioritized by calculating i.e. identifying and collating the population served by each link, and also the type of construction needed for upgradation, etc. and can be determined in GIS. Using the network and routing tools of the GIS software the core network prepared as per the guidelines is presented in Figure 2. The core network map shows the complete thematic features for the existing and the proposed road network as well as the through roads and link roads. Also indicated in the map are the detailed core network attribute information such as (i) link numbers, length and the habitation numbers served directly and/or indirectly by the link, (ii) total population served by the links, (iii) connected and unconnected habitations and the links connecting them, (iv) details of existing road and core network link with surface type and length, (v) summary of all the existing roads in the Block, and (vi) details of the unconnected habitations and links proposed for connecting them.  Figure 2 Core Network Prepared from GIS Base map Detailed Project Preparation Once the alignment is selected for providing connectivity to the habitations, the usual procedure then is to prepare a detailed project report (DPR) for the route. Normally the route selected should be considered as an individual project. The DPR contains detailed drawings of plan, L-section, C-section, detailed survey information on subgrade soil, materials, existing pavement condition, traffic, adjacent land use details, etc (IRC, 2002) along with proposed geometrics, pavement design, etc. All this information is linearly referenced for each link attached to the digital GIS base map. This information once built into the GIS map can be utilized for effective on-line project monitoring activities. The GIS system will also allow the various users/stake holders to monitor the progress and also takes care of all monitoring information in to the system, which will be helpful for further pavement management aspects. Case Study Though DRRP and CNP for Simedaga district have been prepared, DPR for any road in the area has not yet been prepared. In order to explain the development of GIS based road information system (Rao et al, 2002), the DPR data available for a section of NH-2 (Varanasi to Aurangabad) is being used here as a case study. The detailed drawings prepared in digital format as part of DPR and geo-referenced with the help of Survey of India Toposheets (1:50,000) are being used. The base map in the scale of 1:50,000 prepared for the study area is taken up and a portion of the section of NH-2 captured in the base map as shown in Figure 3. All related attribute information available on the toposheets and population census record of the neighboring habitations are also attached to this map. Figure 4 shows the typical plan drawing prepared in AutoCAD environment as part of DPR. This drawing is directly geo-referenced with the base map prepared in the 1:50,000 scale and is attached to the base map as spatial information. All the other attribute data related to the road section are also attached to create a full-fledged GIS for Road Information System. Figure 5 shows the GIS map of the road section with detailed data. Figure 6 shows the typical detailed alignment plan of a portion of the section of the road.  Figure 3 Base Map (1:50,000) of the Study Area |