Abstract

The challenge of insufficient network of meteorological data collection centre has been an age old problem in Africa. It is therefore necessary to encourage a technique that will ensure that data are generated for areas without them. This study is in this regard. 20 years rainfall data were collected from 5 stations in the Western region of Nigeria and analyses were carried out to detect the monthly variations in 2 decades (1985 - 1995 and 1995 - 2004). The study made use of geographic information system (GIS)’s mapping procedure and graphical methods to illustrate that mapping effectively complements the graphical/statistical method, apart from showing spatial distribution, values can be generated for areas without such data. The various maps can also be overlaid in a GIS environment to determine causes and effect of what is being studied among others. The study concluded that mapping could easily complement statistical/graphical approach to studies in spatial science, especially in modeling and data management.

Key words: GIS mapping, monthly and spatial variability, climate data, Western Nigeria.