upon. Therefore, interpreters should come into 
closer contact with specialists in water, soils, 
plants, diseases etc. to appreciate better what 
indicators may be used. Dr. Murtha added that 
keys and catalogues should be used to decide 
whether or not to treat a situation as a crisis. 
Dr. Girard agreed that close liaison between 
remote sensing specialists and specialists in 
various disciplines was important to better 
understand symptoms and manifestations. 
Mr. T. Nguyen (France) remarked to Dr. Sayn- 
Wittgenstein that Commission VII should broaden 
its scope into such areas as medicine and 
mineral exploration who suggested submitting 
this idea as a resolution to Commission VII. 
Tuesday, July 20, 1976, from 9.00 to 10.30 
Session 7 of Commission VII 
Topic: Urban Surveys 
Chairman: Dr. L. Sayn-Wittgenstein (Canada) 
Invited Paper 
Authors: Dr. C. de Bruijn (Netherlands) 
Mr. W. de Haas (Netherlands) 
Mr. P. Hofstee (Netherlands) 
Mr. V. Pollé (Netherlands) 
Title: Urban Surveys with Aerial Photo- 
graphy: a Time for Practice /P VII/04 
Presented Papers 
Authors: Dr. R. Welch (U.S.A.) 
Mr. C. Lo (U.S.A.) 
Mr. C. Pannel (U.S.A.) 
Title: Land Use in Northeast China 1973, 
a View from Landsat-1 PP VII/40 
Author: : Dr. T. Blachut (Canada) 
Title: Use of Orthophotos in Urban Areas 
Generally orthophoto techniques are least suit- 
able for urban areas because of subject and 
because some difficulties occur in the ortho- 
projection of tall buildings. Nevertheless, the 
approach is still useful and can provide a good 
basis for assessing change and recording dy- 
namic effects. The conventional line maps are 
still best where high precision is important. The 
stereo orthophoto procedure was described and 
illustrated. 
The following comments were made in the course 
of the general discussion: 
Dr. Blachut asked Dr. Bruijn if ITC offers a course 
in urban surveys. He replied yes — two courses, 
a 9 month and a 15 month photointerpretation 
course were offered to people from developing 
countries. 
Mr. J. Visser (Netherlands) commented that the 
sophisticated equipment available for differential 
rectification should not detract from the value of 
conventional means of rectification. 
Dr. Blachut commented that orthophotos, espe- 
cially stereoorthophotos, have certain advantages 
in planning and interpretation due to the higher 
planimetric accuracy in comparison with air- 
photos. 
Mr. T. Nguyen (France) commented to Dr. Blachut 
that he agrees with the accuracy statements for 
the orthophoto maps especially for highway 
130 
surveys. Mr. Nguyen then asked Dr. de Bruijn 
if orthophotos have a place in environmental 
planning and impact assessment. Dr. de Bruijn 
replied that not a great deal has been done. 
Mr. S. Móller (Sweden). remarked that geometric 
and "semantic" information (classifications) 
must be combined. Manufacturers are not con- 
vinced of the advantages and have done little 
about it. 
Dr. Blachut commented that there is usually 
about a 10 year lag between completed research 
and implementation but that we should press 
ahead anyway. 
Mr. P. Datta (India) asked Dr. Blachut what scale 
is best for city surveys. He replied 1:1200 to 
1:5000 but scale should also be considered in 
relation to cost. 
Dr. S. Ihemadu (Nigeria) asked Dr. Blachut if 
orthophoto maps could be used to locate property 
boundaries. He replied that orthophoto products 
are capable of accuracies in the order of 20—30 
microns compared with 10 microns for the best 
line maps. Thus the orthophoto maps would be 
sufficiently accurate for many applications. 
Mr. E. Amadesi (Italy) asked what was the best 
scale of orthophotomaps for urban surveys. 
Dr. Blachut replied that for urban work scales 
of 1:1000 to 1:5000 probably were the best. 
Thursday, July 22, 1976, from 15.00 to 17.00 
Session 8 of Commission VII 
Topic: Business Meeting 
Chairman: Dr. L. Sayn-Wittgenstein (Canada) 
1. Resolutions 
Mr. R. Heller (U.S.A.), Chairman of the Resolutions 
Committee, received the resolutions both per- 
taining to Commission VII and I.S.P. in general. 
Some were reorganized, condensed or combined 
with others. The resulting resolutions were read 
to this session. The detailed.original resolutions 
have been given to the incoming Commission VII 
President, Dr. G. Hildebrandt (F.R.G.), for con- 
sideration in the next four years. 
2. Role of Remote Sensing 
A resolution to change the name of 1.S.P. to 
recognize remote sensing was submitted to 
I.S.P. A committee chaired by Dr. F. Doyle (U.S.A.) 
is to propose a suitable name in the next year 
for consideration by the I.S.P. Council. The com- 
mittee was also to study the structure of the 
commissions to adequately cover remote sensing. 
The above is a continuation of work already done 
by Dr. E. Welander (Sweden). 
3. Remarks of Incoming Commission VII President 
Dr. Hildebrandt expressed appreciation for work 
done by Dr. L. Sayn-Wittgenstein in the past four 
years. No specific program has been worked out 
for the next four years yet. Dr. Hildebrandt indi- 
cated that the presently active Working Groups 
will be maintained; some others will be reac- 
tivated. A request was made for ideas for three 
or four themes for the next Commission VII 
Symposium. The intention would be to concen- 
trate efforts in a few areas. It was hoped that the