International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences, Volume XXXIX-B4, 2012
XXII ISPRS Congress, 25 August — 01 September 2012, Melbourne, Australia
| (1) Classify requirements |
| (2) Develop methods |
| (3) = |
| (4) Evaluate |
Figure 1. Examination procedure
3. CLASSIFICATION OF REQUIREMENTS
We asked the municipalities, who are the main users of the
spatial data infrastructure, about the need for planimetric
feature data. In total, we asked 19 departments of five
municipalities in Mie Prefecture in four fields: urban planning,
water supply, sewerage and fixed assets.
The chart below depicts information on the level of importance
and the frequency of change that we obtained from the
municipalities. The importance of a planimetric feature
represents the percentage of departments that need the feature
data for their operations.
.— (Building )
LES
ooueyuodui
MO
v
Low Frequency of change in data High
Figure 2. Distribution of planimetric features by importance
and frequency of change in data
Among the features high in importance were natural or
intangible features: administrative boundaries, shore lines and
contour lines. These are subject to change due to disasters or
large-scale development but do not change greatly with time.
Roads and buildings are artificial constructions. They change
on a day-to-day basis as the result of construction work. The
frequency of change is high for this data. Partial updating is
most effective in maintaining the quality of a spatial data
infrastructure when it is performed on features that are high
both in level of importance and frequency of change. Partially
updating data on buildings and roads would lead to the
sustainable operation of a spatial data infrastructure.
Regarding these two types of planimetric features, we classified
required freshness of data and location accuracy from the
perspectives of governments, which are the subject of our field
study, and the private sector, which does business based on the
data, as shown in the table below. In the following sections, we
propose updating methods to meet these requirements.
Governments Private sector
Up-to-date ^ data is|Up-to-date data is
needed to support of|needed for marketing
Freshness :
people in need of help| and customer data
Building in the event of disaster. | management.
; Standard deviation of|Location accuracy is
Location : ; :
1.75 m is desirable for | not important.
accuracy ;
urban planning.
Up-to-date data is| Up-to-date data is
needed for disaster| needed for use in car
prevention, restoration| navigation systems
and reconstruction | and logistics.
Freshness
Road
following a disaster, as
well as for daily
management of
facilities for utilities.
Standard deviation of|Standard deviation of
Location |0.75 m is desirable for| 0.75 m is desirable for
accuracy |road management. the management of
facilities for utilities.
28
Table 1. Required quality of building and road data from the
perspectives of governments and the private sector
4. DEVELOPMENT OF UPDATING METHODS
4.1 Partial updating of road data
Road construction causes roads to change in shape. With the
exception of expressways and private roads, these are managed
by governments. Governments, therefore, are the first to know
about the changes. In Japan, an as-built drawing is created upon
completion of a road construction work. This drawing is a
topographical map of the site drawn after the work. The map
together with a report is delivered to the client (see the diagram
below).
aw a Draw a detailed map with
topographical intersections, constructions
a and other information, if (1/1000 or more) (1/500 to 1/1000)
necessary.
As-built
construction site.
fm =e = (1/1000 or more)
Topographicaly
ropograph-
ußısop pue uejd *qoxeosay
(blueprint). survey.
Figure 3. Flow of road construction
The government has been encouraging use of the CALS/EC
system since 2000 and has established guidelines on delivery of
electronic document. More and more documents for public
works are being delivered electronically. As-built drawings now
have to be delivered as CAD data when the work is ordered by
the national government. Increasingly, drawings for prefectures
and municipalities also are being delivered as CAD data. This
data constitutes the latest information on changes in roads and
is useful in updating road data.
ical map M map (1/500 or.
(1/1000) sues [Work
mm ' jueprint Create an
' sate E T
! as-built d eus
x drawing E aman
Road pre-desig Detailed design based on a nent
the ordered b E ld
" design y he
as-t
cor
spa
con
ma
dat:
the
If t
4.2
Ch:
nev
bui
