3-Dimensional utility data conversion and utilization
Introduction
Hardcopy utility records, constructed and maintained over time to reflect simply the planimetric
location of underground facilities, are quite often augmented with 'profile' information in order
to show the distance between the ground (typically a road surface) and the underground facilities
- depth of utility. Utility facility profiles are added to the same hardcopy medium as the
planimetric drawing to create a plan & profile drawing. This profile information, initially
captured to increase the accuracy of the underground location information in the case where
digging has to occur in the vicinity of the facilities, can also be used to help build a network
model of the facilities for analysis purposes. This is especially apparent for pipe-based, fluidcarrying
types of utility facilities where the slope of pipes (necessary to properly define the
model) are indicated in the profile view.
Once a complete set of plan, profile, and model records are in place for a utility network, a quite
accurate "definition" of the utility network is available to support the majority of activities -
planning, design, construction, maintenance and repair. However, these three types of records,
having been built up over time using the most appropriate technology available at that time,
typically are not all in a digital format and, almost certainly, are not housed within the same
"database". This diversity results in utility facilities being stored and maintained in potentially
three recording systems: one to represent a facility's plan location, one to represent a facility's
profile location, and one to represent a facility's network model representation. Storing and
maintaining the various components of utility facilities in different recording systems presents
two main problems:
- Invariably, maintenance of utility facility records is not performed equally in each system.
For example, a pipe may be added to the plan and profile records but is not added to the
model either due to time constraints, lack of immediate need, operator skills, or process
flaws. In addition, given the duplicity of various data items among the recording systems,
and in the absence of technology or methodology to ensure a tight link between
representations of facilities in the various recording systems, a pipe's diameter recorded in
the plan system, for example, might not be the same as the same pipe's diameter in the model
system. This is the standard problem with duplicate data storage.
- The components of facility records from the various recording systems: plan (xy), profile (z),
and model (connectivity) cannot be easily integrated and analyzed in concert in a single
system.
These problems ultimately lead to a desire to house and maintain utility records, and each of
their three components - xy, z, and connectivity, in the same recording system in order to
eliminate the problems associated with disparate systems as described above. In order to do this,
typically an intensive data cleaning process is undertaken (known as 'scrubbing'), as well as a
data conversion task that sees current utility records 'translated' to a system capable of housing
and maintaining each of the three feature components previously mentioned.
Information analysis and utilization - requirements first
Prior to converting utility facility data to a single integrated system, the possibilities available in
an integrated digital environment for plan/profile/model data should be considered*. By doing
this it should be possible to completely replace the original source records with the newly
converted data. It is critical at this point however to understand the issues surrounding
conversion and integration of these records as there is a big difference between simply making
digital the existing records and then replicating the original source products from the new
system, as opposed to creating an entirely new data repository and output products. The former
approach, which initially might seem simpler as it introduces less change into the organization,
can lead to additional complications to produce the original products (as originally they were
tailored for a non-digital environment), and limitations in the capabilities of the new system.
Conversely, the latter approach, while initially more difficult due to the degree of change that is
introduced, ultimately provides for a more complete and capable system in the longer term.
The approach described in this paper is one that not only considers the integration of the three
main data sources discussed so far into one data source, but also looks at redefining both in
content and structure the existing output products, and also how, when, and where those products
are used. Of primary significance here is that the three original data sources are migrated into
one data source and the three previous data sources simply become output products rather than
sources.
* Since it is believed that the majority of utility facility data sources, and this author's experience, is with hardcopy
plan/profile maps and digital network model data, the data conversion issues discussed in this paper assume these
types of data sources.
