20 
is located), to see how aerial photography would fit into the local information 
collection procedures. The project, called ELISE (Experimental Local Infor- 
mation System Enschede), started in November 1974 and is still in its first 
phase, that of the inventory of the existing situation. The aims of the project 
are: 
i to see whether aerial photography is a useful tool for planning, admin- 
istration and management in a town of the size of Enschede (+ 150,000 
inhabitants); 
ii to assess the operational requirements in regard to scale, frequency of 
coverage, material, etc; 
ili ^ toevaluate the economic aspects of air photo use in terms of cost/ 
benefit; 
iv to develop ultimately an integrated system of local information handling 
based on frequent airphoto coverage. 
For the period of the research (4-5 years), aerial photography of Enschede 
will be flown yearly by the ITC with its own aircraft. This photography will 
be put at the disposal of the municipality, which can use it for any purpose it 
considers relevant. Where necessary, the ITC will assist with technical advice 
on interpretation procedures or with the training of municipal staff. The 
municipality will report whether airphoto procedures give satisfactory results 
for a given purpose, and how they compare with other methods of data 
collection. 
In a second phase, the photography will be processed by orthophoto 
equipment into metrically correct photo maps. It is expected that these photo 
maps will form the basis of a digital data bank for spatial municipal informa- 
tion. Also, special equipment for stereo interpretation of orthophotos (change 
detection) will be developed. 
À first round of discussions with the technical services of the munici- 
pality regarding their spatial information needs, and how they contemplate 
using aerial photography, has just been completed. A report on the subjects 
and methods of municipal data collection has been published as a result of 
this survey (de Bruijn and Dijkstra 1975). Some results of the first inventory 
are shown in figure 4. 
There is, however, some kind of tautological problem apparent in this 
field. Local authorities try to have administrative procedures for the informa-