GIS for Planning: Road network analysis

Each district has its own vision regarding the infrastructure development. As considered most important part in the infrastructure development, road accounts for most of our development budget. Though rarely used, GIS can be very effective tool to determine road access as well as develop road development plans.

Let us consider an example where one district has its policy to make motorable road accessible to all within 15 minutes( 1KM Average) of walk from any part of the district. In the following example I have plotted access map for Strategic Road Network(SRN) and Rural Road network (Black topped only) to determine the access map under District Transportation Master Plan (DTMP). SRN is the road network built by the Department of Roads where as DDC builds the Rural Road Network.

Creating Buffer Area
1.       Import the Road layer in ArcGIS

2.       Open ArcToolBox -> Analysis Tools -> Proximity -> Buffer

3.       Now open the buffer to see the windows as shown below and set parameters as follows 

     4. After you create the buffer zone the map should look like this 

This map shows the area of Kathmandu district where people have access to motorable road within a walking distance of 1 Km. Analyzing it there seems to be some areas where there is no access to the motorable road within a walk of 15 min .

5. Now let us create the buffer area for black top roads built by DDC under Rural Roads.
 After we create the access map for both type of roads (SRN and Rural road Black Topped) lets fuse two layers to see if the access is improved . 

Even after we fuse two access layer it seems that development of roads have been prominent in those areas where there already was access to the motorable road. Let us now see the complete rural road network to see if there is possibility of road extension.
In the following map I have imported layer of rural road network and symbolized roads accordingly as black topped, earthen and gravel road.

From this map we cans see that there are earthen and gravel roads in the pockets where there was no access to the black topped road hence the DDC can plan to black top the road according to the priority based in the road access.
But another thing that must be kept in mind is that if the newly developed roads will degrade the environment hence it's better to overlay the road network on top of the landuse map to find the forest areas where road extension should be discouraged unless the necessity is acute.

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About Author (pbikrant)

This portal "ICT for Local Bodies" is written by various individuals - ICT Experts and ICT Volunteers working under MoFALD/LGCDP with an aim of integrating ICT at Local Governance. The author is this post is mentioned at the end of the article itself (with their Google+ profile alongside). Learn more about ICT4LB KMDB here.