a transition buffer zone along the joint, but this option does 
not give satisfactory results when the pseudo-colour model 
is used. 
5.6.8 Neat Line Generation 
The mosaicking resulted in a file combining six soft 
orthophotos, the limits of which went beyond the limits of 
the files of the digital topographic data on the scale of 
1:10 000. By specifying the coordinates of the map 
corners, a new SCO file was delimited, the limit of which 
correspond to those of the digital topographic data file. 
5.6.9 Interactive Update 
The first step was to overlay the soft orthophoto and the 
topographic data. Because the SCO (1992) is more recent 
than the topographic data (1988), the planimetric changes 
were identified by doing a visual scan of the combined 
images. The zoom function was used as needed. To avoid 
missing a portion of the map in the revision process a grid 
of 1 km? was used as a template for visually scanning with 
automatically controlled movement to the right, the left, up 
and down made systematic revision possible. 
The erased data was stored as a historical theme, and the 
new data was assigned an identification code. It is 
therefore feasible to display both the old data file and the 
new data file on the monitor. 
An identification code was used for the updates. Since 
measured in the soft colour orthoimage and the coordinates of 
the same point measured in the digital topographic data base, 
The results reflect a mean square error of + 3.6 m. We should 
point out that it was only possible to identify well-defined points 
in the village of Stanley. Outside the village (80% of the 
points) highway, railway intersections, etc. were chosen. 
Digital topographic data standards specify that 9096 of the Well- 
defined features have an accuracy of + 4 m. Even if the 
accuracy of the orthophoto was not determined by a comparison 
with the ground coordinates, the first results indicate that 
creation of the SCO using the existing digital topographic data 
is promising, and that it is possible to contemplate revising the 
digital topographic data base using the SCO. 
COST SUMMARY - MAP UPDATING 
  
  
  
  
  
CARIS offers a user number code of twelve (12) 
characters, the new data has the following code: 
GSL COR 9209 MD 
Cartographer’s initials (Marcel 
Doiron) 
Date of photography 
Revision Method (Orthophoto) 
Digitization Method 
Company (Geomacadie Services Limited) 
5.6.10 Final Presentation 
In order to present an orthophoto prototype that meets the 
provincial standards of map-type presentations, a surround 
was created and combined with the SCO and the 
topographic data. For this, the tool box functions of the 
map editing module (CARED) were used. In addition to 
the information provided in the conventional surround, the 
names of topographic features were accompanied by 
examples in the form of mini-images cut from the soft 
orthophoto. 
6. RESULTS 
The preliminary cost estimate for each stage of the process of 
updating the digital topographic data is shown in Table 6-1. It 
shows the cost to update the digital topographic files with and 
without a soft colour orthophoto series. 
To check the accuracy of the soft colour orthophoto in 
comparison with the digital topographic data, sample features 
were chosen in all parts of the map. The coordinates were 
314 
  
  
  
  
  
  
  
  
  
  
  
  
  
Main Tasks Cost without a Cost including a 
Soft Orthophoto Soft Orthophoto 
Series Series 
Aerial Available from Available from 
Photography Dept of Natural Dept of Natural 
Resources and Resources and 
Energy Energy 
Control 1:10 000 1:10 000 
Enhanced Enhanced Digital 
Digital Database | Database 
Scanning $ 450 $ 450 
Data Input and $ 400 $ 400 
Rectification 
Mosaicking - $ 250 
Updating $ 300 $ 300 
Surround Not Required Not Required 
Quality $ 80 $ 150 
Control 
Field Check Extra Extra 
Digital File $ 80 $ 150 
Management 
and Archieving 
Project $ 90 $ 150 
Management 
| TOTAL | $ 1 400 | $ 1 850 
Table 6-1 
7. FUTURE 
The main objective of the project was to evaluate the soft 
orthophoto technology as a product to update the digital 
topographic data base. A better understanding of the process 
and an approximate revision costs were gained. 
In New Brunswick the next logical step toward soft orthophoto 
and digital topographic data revision is the production of a 
1:50 000 block (25 files). This will allow a refinement of the 
process and the revision cost. 
  
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