prets satellite data by two major methods. Visual image interpretation 
is used mainly in geological investigations, while analogue and digital 
analysis are particularly applied to projects oriented to forestry, 
wildlife and ecology. The Centre possesses an ISI 150 Analogue System 
with a video disk capable of storing up to 600 images and of super- 
imposing six images simultaneously. The Centre's digital system is a 
NORPAK RGP 3050 with PDP/11-34 computer. During the past five years, 
satellite data, used in conjunction with airborne remotely-sensed data 
and field study, has been tested and proven useful for the operational 
programs that will be described in this paper. 
Seven programs have been selected for presentation herein. Because 
of restraints of space it is only possible to present an overall view 
of the method used to apply satellite data to the individual projects. 
Many illustrations which would only have been meaningful in colour have 
been omitted. 
Surficial Geology Mapping of Unmapped 
Portion of Northern Ontario 
Figure 1 shows the status of regional surficial geology mapping in 
Ontario. Areas 1 and 2, comprising the most densely-populated part of 
the province, were mapped at a scale of 1:250,000, largely without the 
aid of aerial photographs but relying on the well-developed road system 
in the area (Chapman and Putnam, 1951). Areas 3 and 4 were mapped at a 
scale of 1:500,000, relying on 1:60,000-scale aerial photography for the 
extrapolation of ground observations, which were limited because there 
were relatively few roads in the region (Boissonneau, 1962; Zoltai, 1962). 
  
In 1963, preliminary maps of Area 5, at a scale of 1:500,000, were 
prepared with limited field survey (Prest, 1963). In 1976, the Centre 
embarked on the surficial geology mapping of Areas 5 and 6, extending to 
the northernmost shore of the province on Hudson Bay. Area 6, hitherto 
unmapped for surficial geology, comprises more than 30% of Ontario and 
includes the Hudson Bay and James Bay Lowlands. 
  
These northern areas are being mapped at a scale of 1:250,000, which 
provides an adequate level of detail and is also a practical working 
scale considering that the area to be mapped requires 35 complete map 
sheets. In addition, maps of the National Topographic Series of Canada 
are at this scale and can, therefore, be used as a base for the surficial 
geology mapping- 
Only the existence of satellite imagery, which permits great savings 
in time and money over traditional methods, made the project a practical 
undertaking at this time. Figure