have been used for an intensive soil capability mapping project. 
The 1:250.000 scale radar film positive strips were used to map 
land units (based on morphological landscape and soil proper 
ties), which were ground checked and produced as 1:250.000 
scale land unit maps. The report (Buurman 1989) states: 
“Because the quality of the STAR-1 Radar imagery is high and 
homogeneous for all of Sumatra, delineation of Land Unit 
boundaries is very accurate for most of the area (accuracy 
becomes less in featureless landscapes)”. Similar projects on 
smaller scales have been completed in other tropical regions. 
Environmental Emergencies/Impact Assessments 
Synthetic aperture radar can play a significant role in providing 
information for environmental emergencies because of its day/ 
night, all-weather data acquisition capability. Thus, at the time 
of a flood, oil spill or landslide, data can be acquired through 
cloud or at night and downlinked in realtime to emergency 
response centres. Lowry et al. (1979) have described the use of 
airborne S AR (the Canada Centre for Remote Sensing’s Convair 
580 X-L band SAR) for mapping and monitoring spring flood 
conditions in southern Manitoba. The area of flooding could be 
delineated and mapped for emergency service planning, hydrol 
ogy studies, claims assessments, and other purposes. Today, a 
system such as STAR-1 would be even more advantageous due 
to its real-time downlink capability and ability to image very 
large areas in short time periods. 
Airborne SAR systems have been shown to be useful for moni 
toring oil spills (e.g., Hawkins et al. 1979), particularly because 
of their all-weather capability, but other sensors are of greater 
value in many oil spill situations. Other emergency situations 
related to landscape alteration (e.g., landslides, earthquakes, 
volcanic eruptions) would also benefit from real-time or near 
real-time data acquisition and analysis based on airborne SAR 
data; however, such studies have not been carried out using 
INTERA’s STAR systems. 
As described for ice monitoring, the provision of real-time ice 
type, location and movement information is critical for opera 
tional drill rig, drill ship and other offshore operations, and the 
STAR systems have provided such information over much of the 
American and Canadian Beaufort seas, the Canadian East Coast, 
Lancaster Sound, and through the Canadian Arctic. 
Environmental impact assessment has a multitude of aspects, and 
SAR data have been tested for only a few of these. For example, 
the aspects related to forestry and agricultural operations have 
been alluded to in the above sections. In these cases, STAR data 
provide information on the type and location of environmental 
disturbance due to construction of settlements, transportation 
infrastructure, clearing of vegetation, industrial operations (e.g., 
sawmills, gas plants, well sites), loss of habitat, alteration of 
drainage, and so on. Environmental aspects related to the 
condition of vegetation or soils are not well documented using 
SAR data, and are likely better carried out using other forms of 
airborne remotely sensed data (e.g., colour infrared photogra 
phy) and/or ground surveys and sampling. 
Topographic Mapping 
The provision of accurate, up-to-date topographic information is 
one of the most critical aspects of any land-based environmental 
mapping program. Topography affects and is affected by all 
earth surface operations and land cover, digital topographic 
information has become even more important with the increase 
in use of geographic information systems and remote sensing 
image analysis in environmental mapping and monitoring pro 
grams. In many regions of the world, topographic information is 
not available or is inadequate in terms of accuracy or complete 
ness, either due to a poor regional mapping program, or problems 
such as cloud cover impeding acquisition of appropriate stere 
ographic imagery. The development of STARMAP, INTERA’s 
SAR-based topographic mapping capability (above), has al 
lowed topographic mapping to be carried out in areas of the world 
not previously well mapped. 
To date, STARMAP has been used in several research and 
development programs in Canada and elsewhere, and commer 
cially in two very large projects (unpublished) in the tropics 
where both the thematic and the topographic content were 
required. In these tropical areas, cloud cover had prevented 
acquisition of recent, high quality aerial photography and the 
map bases were not sufficiently accurate for the client undertak 
ings in the region. The radar data were obtained along with GPS 
data, and very accurate digital radar mosaics and DEMs were 
created, all within a much briefer time frame than was possible 
even were aerial photographs able to be flown. The clients were 
then able to use these mosaics and DEMs for planning survey 
programs and field logistics, and for integration with other digital 
data sets, within a reasonable time frame. 
FUTURE PERSPECTIVES ON GLOBAL MAPPING WITH 
AIRBORNE SAR 
Inkster (1989) demonstrated that the uses of “traditional” satel 
lite data (Landsat and SPOT) in Canada are mainly for mapping 
of renewable and nonrenewable resources, and not for applica 
tions involving rapidly changing surface events (e.g., crop 
monitoring, ice reconnaissance, ocean surveillance). Micro- 
wave systems, such as airborne and spacebome SAR systems, are 
most useful where routine monitoring, particularly in regions 
with persistent darkness or cloud cover, is essential. Rather than 
being competitive with visual/infrared region sensors (such as 
Landsat and SPOT in satellite sensors, or aerial photography/ 
digital visual/infrared systems in airborne sensors), the SAR 
systems are instead complementary. With the advent of space 
bome SAR systems (e.g., RADARS AT, ERS-1, JERS-1), a new 
capability for mapping and monitoring environmental features 
will exist. 
The spacebome systems will define a new role for the more 
familiar airborne microwave sensors, as a “niche” source of 
critical information, rather than an “only available” source of 
information (as is currently the case in some application areas). 
The new markets for airborne systems such as STAR-1 and 
STAR-2 include traditional topographic mapping markets, sur 
veillance of environmental emergencies, and back-up sources of 
information in the event of sudden failure of spacebome systems.