Map revision of Obafemi Awolowo University, Ile-Ife, Osun State, Nigeria
Keywords:
Geographic Information System (GIS), Mapping, Map Revision, Remote SensingAbstract
Day-to-day changes in physical environment due to both natural events and human activities require regular
documentation in form of map for planning an optimum allocation of limited resources. This study acquired and digitized
the orthophoto and satellite imagery of Obafemi Awolowo University; updated the existing map based on the identified
features on the satellite imagery and ground survey method; created a GIS database and analyzed the various changes
found in the study area. Primary and secondary data were used for the study. Global Positioning System (GPS) Receiver
was used to capture newly constructed buildings that were not found on the satellite imagery. The secondary data used
were data derived from existing orthophoto, base map of the study area and satellite imagery. A conceptual model for map
revision was developed and implemented. The source maps were digitized, layers such as road, river and buildings were
created and analysis was performed by overlaying these layers. New features were added, features that no longer exist
were deleted and changed features were amended to reflect the new situation. GIS database, comprising both geometric
and attribute data, was created. The study revealed that percentages of the newly constructed buildings between the year
2012 and 2021 and that of the demolished buildings were calculated to be 17.34% and 11.27% respectively. Analysis also
showed that there was tremendous infrastructural development in the study area in terms of road and building
construction. The up-dated Obafemi Awolowo University map was produced at the same scale as that of the source map,
1:25000. It is concluded that high-resolution satellite imagery and Differential Global Positioning System (DGPS)
observation are effective and efficient methods of updating map. The results of this study will facilitate rapid decision
making and enhance planning of facilities in future development of Obafemi Awolowo University, Ile- Ife.
