d cover 
nalogue 
metric 
Logram- 
ial and 
etrieval 
a varie- 
sors are 
in com 
) of the 
ntation 
er, for 
all the 
| expe- 
rses on 
details. 
| opera- 
| educa- 
adding 
ula, by 
! prere- 
nber of 
eep up 
1e total 
e to re- 
  
SATELLITE DIGITAL DATA IN REGIONAL PLANNING: 
A STUDY AT THE UNIVERSITY OF LAGOS 
By 
S. L. Ekenobi 
Department of Surveying 
University of Lagos 
Lagos — Nigeria 
ABSTRACT 
Digital remotely sensed data acquired by either the American Landsat Satellite or the 
French Spot Satellite Systems can be employed in the production of up-to-date land-use maps 
for regional planning and development. The advantages are two fold. Firstly, the speed of produc- 
tion: It is important that in developing countries, maps for planning and development purposes 
should be ready if possible within a couple of months after the acquisition of the imagery. While 
this speed is impossible by the conventional photogrammetric mapping procedures, it is achiev- 
able by computer supported methods using satellite digital data. Secondly, ground coverage of 
an image frame: While a photograph, taken with a wide angle camera (at elevation 3km) would 
cover about 4.6 x 4.6 sq. km. on the ground, a Landsat frame would covér 185 x 185 sq. km and 
a Spot frame 60 x 60 sq. km. 
The procedure (instrumentation and methodology) for the production of such up-to-date 
maps within weeks of acquisition of data Is now being developed at the University of Lagos, 
using Landsat digital magnetic tape data, equipment donated by the Volkswagen Foundation of 
West Germany and a grant from the University of Lagos. 
“ INTRODUCTION 
Maps for regional planning and development should be quite up-to-date. In developing 
countries where the need for these maps is critical, the difficulties in making them always avail- 
able is rather acute.This paper discusses the productionof very up-to-date maps which are obvious- 
ly better than those made from 10 to 30 year old photography. 
Developing countries should see the application of satellite technology to mapping as timely. 
At the present stage of the technology however, maps therefrom cannot be as accurate as the 
often desired 1:50,000 maps. On the other hand, a map can be ready within weeks of the acqu isi- 
tion of the satellite imagery. 
Processing is by the computer. Important is an accurate base-map whose age is not important, 
since it contains only permanent features (geographical and political information) on which 
terrain features, imaged at any one time by the satellite, are ‘’hung’’. Useful results are thematic 
maps which include those of human settlement, surface water, agricultural and forestry land as 
well as those for the study of effects of desert and ocean encroachment.