ata upgrade
of 1:25000
led existing
nd Mapping
of CRONO
Companies
le a strategy
control of
m. Quality
'opographic
files:
DINGS.dgn
ITY.dgn
[TISED.dgn
INYMS
ontractorID
resent map
file format.
> shown on
Figure 2: Example of DTM data
Sources which are used for control were Data inventory report,
Data upgrade specification and Mapping catalogue. For the
control of toponyms there were aslo the old maps of TK25
used. Data structure control included was done acoording to
mapping catalogue which describes level, color, line style and
weight for linear objects, cell name for point elements and
representation point (text) for areal objects.
Control of topology included checking closing areas, duplicate
lines and boundaries, open boundaries, number of
representation points in areas, missing representation points in
areas, detecting unused boundaries, etc.
Control of DTM included also checking of structure elements in
files and deriving DEM from delivered elements and detecting
of possible errors.
2.3.2 Quality methods
There are two methods for quality control:
- Visual control with Microstation and SCOP
- Automatic control of data structure and topology
(using FME).
Microstation was used for visual control of data. There was a
system to control elements, which were wrongly represented
before data upgrade process. Mostly, bridges were wrongly
represented, roads were without center lines, waters were not
represented under bridges (Figure 3) and culverts, creating
centerlines were also not enough precise (Figure 4).
Figure 3: Water line not represented under bridges
171
Figure 4: Unprecise creating of road centerlines
Visual control of DTM was done with the help of derived shade
(tiff format) and DEM (dgn format) as shown on Figure 5.
Some questionable parts on raster file are checked.
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* a a ss aims a =
4 * m -* m» » €" » *
Figure 5: Visual control of DTM
Automated quality control was done with FME (Feature
Manipulation Engine) software. Partly based on FME training
and partly with help of CRONO GIP consultants in CGI the
FME factory files were used for checking the structure of
datasets and for checking topology. The inputs for control of
dataset structure were all legal levels, colors, line styles and
weights for linear elements, for point elements input there was
a list of symbol (crotis.cel file) and for area elements a list of
codes (representation points). FME detected all open
boundaries, unused boundaries (which are not necessary for
creating area topology), missing classifications points (text
codes), duplicate classifications points, overlapping lines and
boundaries, self intersected lines and boundaries.
2.3.3 Results of control
After the control, the results were divided to:
- . Comments connected to undefined specification
- Comments connected to misinterpretation of
specification
- Comments to topological processing.
In the process of quality control CGI detected some cases which
are not enough described or are not described in Specification.
Typical example of that case is joining of road center lines.
There was no rule for joining narrow paths with road center
lines which are very important for creating road network
topology (Figure 6).