y related. 
ill of the 
e to view 
res which 
e features 
> the DOI 
ired. The 
) the limit 
esolution) 
e and can 
formation 
| data sets 
ed with a 
toba Land 
rs needed 
traditional 
| coverage 
with GIS 
| to create 
yment was 
| user and 
| access to 
other data 
ing digital 
eat deal of 
cept. 
nd related 
ese data to 
e included 
] elevation 
orks, and 
ice system 
ate all data 
ducts; 2 m 
)r resource 
  
areas. In order to provide users with a hands on view of DOI three projects were undertaken in 
1992. Two separate areas were chosen because of their potential GIS application, one having an 
agricultural aspect and the other having a land use planning aspect. The third project provided 
urban aspects. In 1993 a further rural area was completed to provide reference mapping for a 
major water resource study. 
For the rural projects, aerial photography at a scale of 1:60,000 was obtained under contract by 
Northwest Geomatics Ltd. of Edmonton, Alberta and combined with ground control information 
gathered from existing sources. For the urban project, aerial photography at a scale of 1:6,000 
was obtained under contract by Airquest of Winnipeg, Manitoba. DOI production, using the I2S 
system, was contracted to Intera Technology of Ottawa. 
In the rural projects the resultant data files cover 10 x 10 km on a UTM grid whereas in the 
urban areas the files cover 1 x 1 km on the UTM grid. The grid layout was chosen for ease in 
handling within the computer systems. 
To date the 125 rural data files which have been produced represents approximately 10 % of the 
total agricultural area of the province and 65 urban files have been produced in three separate 
geographic areas. All of these data have exceeded the expectations of the original requirements 
both from the point of view of acceptability as well as the accuracy and cost. Some 
modifications have been made in the specifications for these data sets. For example, aerial 
photography is now obtained on a precision sheet centered basis in order to maximize the DOI 
production throughout. Additionally, the amount of ground control required is minimized by 
obtaining GPS positional data for each camera exposure station. Both of these changes have 
improved the spatial accuracy and have reduced the overall cost of the final product. Plans for 
1994 have not been finalized but a proposal has been initiated for obtaining full coverage of the 
agricultural areas in a major project to be completed within one year. 
DOI WILL CHANGE THE WAY WE PERCEIVE GEOGRAPHIC DATA 
In the past, interpretation of geographic features from aerial photography has been performed 
by people with specific training in the theory and operation of sophisticated optical mechanical 
measuring systems. People have the best skills for this type of interpretation. Computers have 
great difficulty in recognizing patterns and associating these patterns with correct geographic 
features. Some advances have been made in computer assisted interpretation of binary raster 
images and multi spectral remote sensing data, however, classification of continuous tone or grey 
scale raster data is less than perfected. DOI provides the opportunity for any user to perform the 
interpretation they require for their own use. Utility companies, for example, have been able to 
improve the spatial accuracy of their facility records by digitizing pole locations directly from 
the DOI. Other users can readily locate their data sets by referencing key objects such as roads, 
lakes, vegetation boundaries and built up areas. 
The spatial measurement process, which is a fundamental component of conventional 
photogrammetric systems, can be readily performed with GIS tools and linked directly with the 
associated data base for subsequent analysis. The GIS user does not need to rely on someone else 
to interpret the image for them however if there is concern about the integrity of data digitization 
285