Monitoring Trends in Urban Growth and Surveying City Quarters in Ouagadougou, Burkina Faso Using SPOT‐XS

Abstract

City planning agencies in developing countries lack important information on the generally rapid urban development which is taking place. Remote Sensing is a promising technique which provides that much needed information. A time series of four SPOT‐XS images of Ouagadougou in Burkina Faso is analyzed to assess the usefulness of SPOT imagery for urban planning, and to determine the growth of Ouagadougou between 1986 and 1997. Another research objective is to examine the possibilities which SPOT images offer for the socio‐economic classification of city sections. Both traditional image classification methods and a new contextual approach are applied. The latter approach aims at identifying structural patterns within the city boundaries which can be used as indicators for district function and status. Aerial photos and field surveys are utilized as ground reference data. The conclusions are that SPOT images are useful in surveying urban expansion over time but that it is difficult to identify the socio‐economic function of city districts. The 20 × 20 m spatial resolution is not sufficient to bring out some of the subtle pattern differences between the city quarters. The contextual approach yielded some promising results by separating squatter areas from others but it was not capable of differentiating pre‐colonial parts and old periphery sections. High resolution images of the recently launched Ikonos satellite with a pixel size of 4 × 4 m may provide a better spatial resolution for the contextual approach.