between percentage error and category percentage area. These suggest that when 
the category percentage area is under 20% then there is a need to increase the 
density of observations to obtain acceptable levels of accuracy. There appears 
to be no advantage in increasing the density of observations above the 0.5 ha 
grid when this value of 20% is reached. 
CONCLUSION 
In a country like Nigeria, with its rapidly growing urban centres, there 
is an urgent need to monitor urban development. Aerial photography provides 
the basis for a quick, cost-effective method of gathering urban land use data. 
The method of sampling offered here, is well within the resources of other 
Nigerian researchers and there is a need, now, for others to investigate this 
initial methodology and apply it to their specific requirements. In particular, 
the urban land use classification should be tested in other Nigerian cities to 
identify any modifications which might be necessary to enable it to be used 
nationally. 
Clearly there is much to be done, but it is hoped that this study will 
make some useful contribution to the acquisition of the information so urgently 
needed for urban planning and development monitoring in Nigeria. 
REFERENCES 
WIKRAMATILEKE, R., 1959. The Problem of Land Use Mapping in the Tropics: an 
Example from Ceylon. Geography, Journal of the Geographical Associa- 
tion, U.K., No.204, Vol XLIV/2, 79 - 94 
KIO, P.R.O., 1971. The Status of Aerial Photo-Interpretation in Nigerian 
Forestry. Nigerian Journal of Forestry, Vol 2, 64 - 68 
  
MORTIMORE, M.J., ADAMU, M. and OKOLI, G.I., 1966. Land Use in Kano City and 
Township. Occasional Paper No.3, Department of Geography, Ahmodu 
Bello University, Nigeria 
ADENIYI, P.0., 1980. Land Use Change Analysis Using Sequential Aerial Photo- 
graphy and Computer Techniques. Photogrammetric Engineering and 
Remote Sensing, Vol.46 (II), 1447 - 1464 
  
ESIN, E.U., 1981. A Methodology, Using Aerial Photographs, for Mapping Urban 
Urban Land Use in Nigeria. Unpublished M.Phil Thesis, University of 
Aston, Birmingham, England 
  
  
EMMOTT, C. and COLLINS, W.G., 1980. Air Photo Interpretation for the Measure- 
ment of Changes in Urban Land Use. Proceedings of the 14th Inter- 
national Congress of the I.S.P., Commission VII, Hamburg. 
  
  
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