7917. 
NATIONAL SURVEY OF 'DEVELOPED LAND' 
USING AIR PHOTOGRAPHY AND SATELLITE DATA 
T FP SMITH 
DEPARTMENT OF THE ENVIRONMENT UNITED KINGDOM 
Summary 
Conventional field survey to obtain land-use information at national level 
is tedious, time-consuming and expensive. Surveys by remote sensing to 
acquire nation-wide data reduce time and manpower and can be carried out 
regularly in order to monitor changes and discern trends. The Surveys can 
be comprehensive covering the whole country and all the data can be 
related to a single time base. Finally and most important, the same 
criteria for classification can be used consistently in each survey. 
A complete national survey of Britain was flown at 1:60,000 scale using 
panchromatic, vertical photography. The quality of the photography is 
excellent and even at this small scale it was possible to detect up to 28 
distinct urban land-uses even as small in area as 0.25 hectares. However, 
information of this detail and size of area could not be consistently 
interpreted to ensure that all areas in each of the 28 categories would be 
distinguished. Moreover, accurate plotting and measurement of areas only 
0.25 hectares in size raises serious problems, particularly for the 
standards required in monitoring changes of areas as small as this. 
The photography was interpreted to map all areas of 5 hectares and above, 
classified by 5 main urban land-uses: residential, industrial/commercial, 
educational/community, transport and urban open space. 
Each land-use parcel was digitised for computer measurement and aggregation. 
The computerised data can be used with other digital data such as Census 
information about population, housing, employment, transportation etc. 
Conventional air survey will continue to provide data which can be usefully 
applied in regional planning. Presentation of data is one of the main 
bottlenecks in all information systems and the immediate aim should be 
improvement in its presentation as useful information. 
Introduction 
During the last 30 years, information about land use in the UK has been 
derived from secondary sources, the most important being: 
i. A yearly Census by the Ministry of Agriculture which 
produces statistics on losses of land from agricultural 
use. 
ii. Surveys by Local Planning Authorities, mostly obtained 
by field work undertaken in the early 1950s. 
iii. The Second Land Use Survey of Britain, directed by 
Alice Coleman, carried out between 1960-1966. 
The lack of reliable land-use information since the 1950s has led to 
uncertainty about the pattern o. urban development and about the relative 
importance of factors responsible for tl.e expansion of urban areas.