Power |
Telecom |
Transport |
Others
Optimization of bus stop locations using GIS as a tool for Chennai city - Case study
Methodology:
Data Collection: The case study is based on the data collected on ground using GPS and the map of the road network. Exhaustive work has been done in the field collecting the co-ordinates for each bus stop locations. There are about 41 bus - stops between vadapalani and besent nagar, which is the study area. There are about 21 roads in the selected route. The data collection is done taking into consideration the accessibility of the road in both ways. Most of the collateral data are collected manually which is the scope of development in the future study in the same area. The network map is digitized. Digitization is done manually using On-screen method. The errors in the original maps will be transferred and they are likely magnified when digitized using GIS. Here arcs and nodes are defined by the user. The advantage here is the ease in the ability to spot the digitizing errors. Post digitizing process generally includes building topology and cleaning the coverage. Finally the errors are corrected for each of the GIS layers. Tic points are to be digitized for calculating the accuracy and for performing projection. The control points are collected using the GPS from well identified, prominent locations such as road junctions which are distinctly visible on the map. Co-ordinates for control points are collected in more than 4 points which is the minimum requisite to increase the validity of the data. The tics can also be used for transforming the coverage to the required projection so that real world co-ordinates are obtained for our analysis. The projection used here is polyconic which is considered the best suited for India. Arc View and Arc Info are the softwares used for digitization, transformation/projection and analysis. 
Analysis: After the data collection, the next step is the analysis. The co-ordinates of the bus stops are known using which their positions are determined on to the transformed map to the geographical co-ordinates. These are taken to as point data which give the bus stop locations. Buffer analysis is made to determine the area of influence. The minimum and maximum distances are given which are given as buffer distances. If there is overlap in the buffers then a common point can be considered for the location of the stop such that there is no overlap. This point is selected considering other criteria also. Confluence of all parameters is essential before arriving into any decision. The similar way if the distance between two buffers are more this indicate that the area in the in between region is not properly served by any of the bus stops. In these case new bus stops can be created. Thus it is necessary to calculate based on all the parameters that none of the areas are under served or over served. The route analysis is made, the impedance value and the speed are given based on the vehicular volume on each road. The bus stops can be minimized in roads where there the existing traffic is high, additional postioning of these stops would add up to the traffic congestion. The locations of important centers such as hospitals ,schools etc are also estimated for their proximity to the stops using the route analysis module. The time gained due to the reduction of the stops vice versa is also projected by having each locations as a node and by giving a positive or negative value for the calculation of impedance. The demographic characteristics is also computed . Conclusion: A multi criterion analysis is thus performed taking into consideration all the parameters explained above in detail. It was found that the bus stop location could be changed in some places. In few sites the bus stops were too closely located which results in unnecessary loss in time in space. The area satisfies all the conditions set forth and it is optimal approach to take out that bus stop which was found on our analysis it would reduce the precious travel time of the commuters and also the even more valuable commodity in urban area ie the land. Another solution obtained is the optimal location for the creation of new bus stop, that would serve the population that earlier suffered .This way GIS can be used in all the ways to carefully analyze all the criteria and successfully give good solution that is acceptable to everyone. The study presented above has been made only for a single bus route. This can be extended to the whole of Chennai. The increase in use of high spatial and spectral resolution satellite data for analysis can make the whole job much simpler. References :
Page 3 of 3
| Previous | |