actual observations in the field or on photographs. Such data are an essential 
base for the development of rational planning strategies, research programmes, 
population studies and urban development schemes. In developing countries land 
use surveys are difficult to carry out owing principally to shortages of funds 
and trained personnel, as well as to the difficult field conditions often 
encountered. Conventional methods of land use data collection are expensive 
and time-consuming, so that in many cases data often becomes available only 
after the decisions (for which it was required) have been made. 
The investigations reported here concerns the application of sampling 
techniques so as to provide a simple and therefore rapid and inexpensive means 
of collecting information on urban land use. 
URBAN LAND USE CLASSIFICATION 
  
The literature concerning land use studies in Europe and North America 
indicates that the compilation of satisfactory classification schemes is a 
difficult art which has yet found few adepts. This is seen to be even more 
true when attention is turned to the tropical lands, and may be attributed to 
lack of funds, expertise and incentive, as well as to a shortage of research 
material. This is unfortunate since mid-latitude techniques, criteria, classi- 
fications categories and nomenclatures do not fit tropical conditions and do 
not produce effective land use maps (Wikkramatileke, 1959). 
In Nigeria there has been no attempt to produce a national land use 
classification scheme. In the Cross River State and the Western States the 
rural land classifications which exist have been developed for forest inventory 
purposes (Kio, 1971). The Nigerian Radar Project (NIRAD), commissioned in 
1976 by the Federal Government for the mapping of vegetation over the whole 
country, employed a land cover classification scheme of a generality appropriate 
to the radar imagery employed. 
In the case of specifically air photo based urban land use surveys, classi- 
fication schemes have been compiled for the northern city of Kano (Mortimore 
et al., 1966) and for the capital city, Lagos in the humid tropical coastal 
zone, (Adeniyi, 1980), The Kano classification is appropriate for the type of 
land use characteristic of an historic city on the edge of the Sabera, but has 
little relevance to the requirements of a rapidly developing city in the humid 
tropics. 
The Lagos classification takes into account the complex nature of urban 
land uses and also the specific characteristics of the tropical city especially 
in the details of the residential and commercial categories as well as those 
of the non-urban land. Unfortunately the resulting scheme has become a rather 
complicated list rather than a sound, hierarchical classification. The inclu- 
sions on the same hierarchical level of such characteristics as plot size, age 
of buildings, style of buildings, number of floors and presence or absence of 
vegetation, detracts from the usefulness of the scheme. 
The Calabar urban land use classification was compiled as a strictly 
hierarchical structure taking into account the method of survey, interpretation 
of 1:6000 black and white aerial photography, land use characteristics identi- 
fiable in the area and existing attempts to classify land use in Calabar. The 
complete classification is given in Table 1. The scheme was compiled so that 
additional categories could be added, even at the first level, without altera- 
tions to the basic structure thus, it is hoped, it will be possible to adopt 
the scheme for application to other towns in Nigeria or even in other tropical 
countries. 
826 
nz 72 
— — e € m