| dc.description.abstract | Geographic Information Systems (GIS) is an indispensable tool for automating processes in various disciplines. Road chainages are the most appropriate way of geographically locating areas of interest in the road sector. An intuitive method for referencing therefore serves to enable users of road data to locate whatever information that they need. In this project such a referencing system has been employed and it is easier to mark a linear referenced hatch line (chainage), than to memorise the northings and easting of the same point where one has interest in.
The main objective of this study was to map a linearly referenced road section (Machakos -Syongila) C97 road to be used in subsequent mapping of KeNHA roads. Data used was collected from journals (The Kenya Gazette), AutoCAD design drawings, and Survey of Kenya registry index maps. After georeferencing, Registry Index Maps were digitised delineating only the land parcels abutting the right of way otherwise known as the road reserve. Road roughness index also was mapped from the information provided by the maintenance department at the Kenya National Highways Authority. From the centreline which was plotted for the whole stretch of the road, a route feature dataset was created using GIS analysis techniques that enable hatching of the station lines along that same centreline. A tool was customised to enhance the identification of the route at any point.
The key results included a digital map of the road with referenced location chainages overlaid with other datasets that are incorporated as the land acquisition data and International Roughness Index (IRI) along the road.
In conclusion, this research demonstrated that it is possible to map the acquisition, road roughness and chainages at any point along the centreline using a linear referencing method. The research project gives several hard copy maps and a web based map as products for the road, covering 108+800 km. Conversion of point features to events was possible but polygon features are quite challenging to be mapped in the same way as point features and line as well. Linear referencing is one dimensional, but if accuracy is of importance then the coordinates for each station lines need to be documented | en_US |
