frequency domain through the application of Fourier 
transforms. The supervised classification routine can also be 
run in batch model. 
The rectification and orthoimage program is developed for 
the geometric correction and registration of raster images. 
Ground control points can be selected in a raster image and a 
digital map which are simultaneously displayed in separate 
windows. The evaluation of the selected points based on 
statistical testing is possible. The affine, polynomial, 
projective and spline transformations are provided for the 
geometric registration. Resampling can be performed by the 
nearest neighbour algorithm or by the bilinear and bicubic 
interpolations. Analytical photogrammetric operation, based 
on the collinearity equation, are available to deal with 
digitized frame camera photographs. Digital orthoimages 
and mosaics can also be generated if a digital elevation model 
(DEM) is at hand. 
The Vector Orientation program is used to transform an 
existing map file from the ground coordinate system into a 
specified image coordinate system and to perform the inverse 
transformation. It can be performed in either two- or three- 
dimensional space. Correction can be applied for relief 
displacement if a DEM exists. 
Vector transformation has significant advantages where a 
map and an image must be in registration for the purpose of 
analysis and information extraction but a permanent 
georeferenced image is not required. The map file is 
temporarily registered to the image and then the new 
information which has been derived and vectorized is 
transferred back to the correct coordinate system. This 
approach avoids the need for the computationally demanding 
resampling and eliminates the risk of introducing undesirable 
effects on the radiometric characteristics of the image data, 
which may occur during resampling. 
5. FUTURE DEVLEOPMENTS 
An integrated GIS/IPS prototype facility is now in place, 
which provides interested users with a wide variety of digital 
image manipulation functions. There are, however, certain 
bottlenecks which make the operation of the system 
somewhat awkward. For example, the raster image display 
and interactive image processing functions are rigidly 
embedded in the Primary Graphics module and it is difficult 
to utilize it elsewhere. On the other hand, the interface of 
CRIS with the three main line CARIS packages is too loose 
and not user friendly. 
Future plans call for the development of a CARIS Shell 
which will be responsible for acquiring commands from the 
user and passing them on to the relevant task. The existing 
CARIS data structure which is needed by almost all tasks 
will be placed in a Shell. All raster image extension (RIX) 
operations will be bundled into a stand alone task and placed 
into the Shell so that it can be invoked by either CARED or 
CARMEN. 
The CRIS batch operations will be handled through the new 
CRIS Server which will facilitate the off-line transfer of 
image data to and from the mainstream CARIS and the 
various image processing programs. This arrangement will 
encourage the expansion of the program library through third 
party software development without having to be concerned 
with the CARIS data structure. The new configuration is 
shown in Figure 5. 
6. CONCLUSIONS 
CARIS/RIX provides GIS users with a tool for the 
exploitation of digital images as a data source. It supports 
on-line image analysis and information extraction in a 
merged raster-image/vector-graphics display and 
778 
incorporates all the commonly used off-line image 
processing functions. This hybrid environment created for 
integrated processing of spatial information is, no doubt, a 
valuable asset in change detection map revision and resource 
mapping. The stage is also set for the development of a 
knowledge-based image analysis strategy by taking 
advantage of the information stored in the GIS. 
ACKNOWLEDGEMENT 
This research and development work has been funded under 
the Canada/New Brunswick Subsidiary Agreement on 
Industrial Innovation. 
REFERENCES 
Derenyi, E. and R. Pollock (1990a). “Extending a vector- 
based GIS with raster-image handling capabilities.” 
Proceedings of the GIS for the 1990s National Conference, 
Canadian Institute of Surveying and Mapping, Ottawa, 
March 5-8, pp. 1463-1473. 
Derenyi, E., and R. Pollock (1990b). “Extending a GIS to 
Support Image-based Map Revision.” Photogrammetric 
Engineering and Remote Sensing, Vol. 56, No. 11, pp. 
1493-1496. 
Derenyi, E. (1991). “Design and Development of a 
Heterogeneous GIS.” CISM Journal ACGC, Vol. 45, No.4. 
Reedijk, W. (1990). The Design and Implementation for 
Raster Data Handling Capabilities for Geographic 
Applications. M.Sc.E. Thesis, Department of Surveying 
Engineering, University of New Brunswick, Fredericton, 
N.B., Canada, April. 
USL (1991). CARIS Products Description. Universal 
Systems Ltd., Fredericton, N.B., Canada, May.