Panel Discussion 
Topic: Role of Remote Sensing in Environ- 
mental Monitoring 
Moderator: Dr. S. Schneider (F.R.G.) 
Panelists: Dr. R. Ellefsen (U.S.A.) 
Mr. V. Zsilinszky (Canada) 
Mr. T. Nguyen (France) 
Dr. Ellefsen described and illustrated the use of 
computermap produced on the basis of Landsat 
data in the monitoring of changes in land use. 
When comparing computermaps produced at 
various times to contemporaneous manual maps 
the results proved to be good. He further estab- 
lished that by comparing computermaps of 
various age with each other it would be possible 
to follow the changes in land use PP VII/11. 
Mr. Zsilinszky descriced and illustrated the use 
of NOAA and Landsat imagery at the Ontario 
Centre for Remote Sensing. Applications, based 
on visual photointerpretation techniques had 
been effective in monitoring changes in the 
following areas: flooding, progress of melting 
snow and ice, water pollution, fume damage, 
effect of highways on water courses and sur- 
rounding vegetation, forest harvesting and forest 
fires. 
Dr. Schneider gave a synopsis of his paper 
"Monitoring of Polluted Rivers by Remote Sen- 
sing Methods" PP VII/34. 
Mr. Nguyen described a warning system based 
on remote sensing for monitoring marine pollu- 
tion from oil spills and other causes. The system 
developed for French waters has three main 
functions: 1) detection of oil spills and layers of 
hydrocarbon derivatives in sea water, 2) alerting 
controlling authorites, and 3) alerting ships or 
other sources in order that corrective action may 
be taken. The sensors used are: microwave, 
laser, aerial photographs, high altitude radar, low 
altitude infrared detectors. 
The following remarks were made in the course 
of the subsequent general discussion: Dr. G. 
Hildebrandt (F.R.G.) asked Dr. Schneider if thermal 
and other emissions at the water surface could 
be used to characterize water beneath the 
surface. He replied that elevated temperature 
and the presence of chemical pollution may 
affect vegetation which can then be used as an 
indicator of the condition of water. Otherwise 
water samples are required to verify the interpre- 
tation based on surface emissions. 
Dr. A. Fontanel (France) asked Dr. Schneider if it 
is possible to quantify water surface temperature. 
He replied that it was possible within 0.5°C but 
the temperature 50 cm below the surface is 
usually 1—1 1/2°C higher because of the effect 
of evaporation at the surface. 
Mr. R. Heller (U.S.A.) asked Mr. Nguyen if solid 
state, charged couple detectors are used in the 
French system and if routine surveys based on 
the method were being used. He replied that 
standard military infrared scanners were used 
and, in reply to the second question, that some 
routine missions are being used now and that 
by 1977 the system should be fully operational. 
Dr. S. Paul (France) asked Dr. Schneider what he 
considered the best electromagnetic window for 
infrared scanners used to collect water data, 
what was the angular and thermal resolution 
that can be expected, and the best means of 
disseminating the results. In reply to the first 
question, Dr. Schneider indicated the 3 to 5 or 
8 to 12 micron bands, for the second the thermal 
resolution was about 0.5°C, and in response to 
the last question the results should go directly 
to the local planning authorities. 
Mr. A. Boberg (Sweden) asked Mr. Nguyen what 
luminescence methods and what sensors he 
used. He replied that a 2KW ultraviolet source 
was used to illuminate and excite the hydrocar- 
bons resulting in a florescence in the visible 
spectrum which is recorded by the TV system. 
Dr. Schneider asked Dr. Sayn-Wittgenstein if it 
would be desirable for the definition of "moni- 
toring”, "inventory" and "surveillance" to be put 
in the Commission VII records. Dr. Sayn-Wittgen- 
stein subsequently provided the following defi- 
nitions: Monitoring, as defined in the Report of 
the Study of Critical Environmental Problems 
(MIT Press) is "The systematic observation of 
parameters related to a specific problem designed 
to provide information on the characteristics of 
the problem and their change with time". Sur- 
veillance is a specific form of monitoring in 
which the objective is to establish if limits and 
standards set by legislation or agreements are 
adhered to. 
Monday, July 19, 1976, from 10.30 to 12.15 
Session 6 of Commission VII 
Topic: Vegetation Damage 
Chairman: Dr. L. Sayn-Wittgenstein (Canada) 
Invited Paper 
Author: Dr. P. Murtha (Canada) 
Title: Vegetation Damage and Remote 
Sensing: Principle Problems and 
Some Recommendations /P V///08 
Presented Paper 
Author: Dr. C. Girard (France) 
Title: Utilisation de la télédétection dans 
la connaissance des dommages 
causés aux cultures PP VII/16 
A general discussion on vegetation damage 
resulted. The following remarks were made: 
Mr. A. Jones (Australia) remarked to Dr. Murtha 
that he seemed to close the question of the 
ideal film/filter combination. In Australia the 
question is still very much alive. The conclusions 
based on experience in cool temperate latitudes 
therefore are not universally applicable. Also, 
the role of season should not be down-played. 
In reply, Dr. Murtha suggested that remote 
sensing should include the background idea of 
the sensing system. He also stated that in the 
use of IR-films there appear certain difficulties 
the cause of which is not fully known. 
Mr. S. Môller (Sweden) remarked to Dr. S. Schnei- 
der (F.R.G.) that many factors affecting classifi- 
cation based on photointerpretation are not well 
understood. This affects especially the detection 
of changes in the landscape. Dr. Scheider replied 
that greater use should be made of indicators 
of condition — that is an indirect method of 
interpretation and classification would be called 
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