INTRODUCTION 
An efficient system for the collection, processing and presentation of land use 
information is an essential pre-requisite for land use planning. Land use surveys 
by traditional ground-based methods are costly and slow, as well as difficult, 
especially where resources and trained personnel are scarce. 
Fortunately, it is often the case in such areas that extensive coverage of aerial 
photography, and even sequential coverage, is available as a result of 
photogrammetric mapping programmes. Thus, historic as well as up to date 
information on land use exists in the form of air photographs and requires only 
the appropriate methodology to make is accessible to those who require it. 
Such a methodology should combine simplicity with flexibility and should be 
user-amenable, i.e. it should be accessible, at all stages, to the prospective user 
of the information. This enables such essential considerations as classification, 
levels of accuracy and modes of information presentation to be dealt with in 
the most appropriate way. 
THE USE OF AERIAL PHOTOGRAPHY 
A recent extensive use of aerial photography was the Department of the 
Environment survey of developed areas in England and Wales (Smith et al, 
1977). The use of small scale, 1:60000, photography and a limited number of 
broad categories enabled this survey to be completed speedily. The 
methodology employed comprised three stages: interpreted land use units were 
recorded on transparent overlays to 1:50000 maps, the boundaries were 
digitized and the data then stored and processed by computer. The products 
were map overlays and tables of land use areas. 
An alternative to boundary digitization of interpreted land use polygons is to 
convert the areal units to cellular format. Here, the land use boundaries 
derived from air photo interpretation are transferred to a base map and over 
this is placed a square grid with cells of the required size. The computer input 
comprises the location code and the appropriate land use code for each cell. 
The computer output comprises a variety of area data listings together with 
computer graphics displays in the form of grid pattern maps of land use. 
This method was used for the monitoring of land use changes in the Boston and 
Newhaven areas of the USA (Lindgren et al, 1974) and more recently for land 
use change analysis in Lagos, Nigeria (Adeniyi, 1980). 
DIRECT RECORDING 
The system of recording interpreted land use on overlays then either boundary 
digitizing or converting to cellular format has been commonly employed. This 
is unfortunate since this process of recording land use in laborious, it can lead 
to inaccuracy of interpretation and recording and is in many cases unnecessary. 
Whilst the combination of user-interpretation and computer processing is an 
essential element of any efficient land use survey system, the recording of 
interpreted data need not involve the compilation of overlays. A more efficient 
and simple approach is to use a pattern of grid cells or perferably dots directly 
as the recording base. Land use information in this form can be fed directly 
into the computer. Furthermore, it has been shown (Emmott and Collins, 1979) 
that the areal data so acquired are of an accuracy acceptable for most 
purposes. It has been shown also that not only is the interpretation of land use 
at point locations (i.e. on a dot grid) easier than judging dominant use within a 
grid square, but that the data so produced are at least as accurate. 
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