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QUALITY MANAGEMENT SYSTEM IN PHOTOGRAMMETRIC PROJECTS -
APPROACHES AND EXPERIENCE IN SLOVENIA
M. Kosmatin Fras
Geodetic Institute of Slovenia, Jamova c. 2, SI-1000 Ljubljana, Slovenia - mojca.fras@geod-is.si
Commission VI, WG VI/3
KEY WORDS: photogrammetry, quality, control, measures, evaluation methods
ABSTRACT:
Management in many organizations still thinks that a quality program is an unnecessary expense and an impediment to productivity.
However, the practice shows different situation. For example, in Slovenia a lot of spatial data have been collected in the last decade
with new technologies while at the beginning not enough attention was given to the quality of these data. Usually, very high
financial input is necessary for bulk spatial data collection thus it is essential that data are of required quality. There is concern for
data quality because, generally, production of spatial data by the private sector is increasing, where there are mostly no detailed
quality standards. Photogrammetric working procedures are quite complex and it is important to plan carefully the working
procedures, the individual working phases, the timing and also the time frame for the quality control by the partners. This is of
special importance as the whole work is not always executed by the same enterprises and the tasks of the main contractor and the
sub contractors have to be coordinated. It must be a principle that all individual steps are controlled thoroughly within the enterprises
and that the national authority also disposes on the necessary documents for an independent and thorough quality control. In the last
few years, some control procedures were introduced in Slovenian national projects that yield significantly to improvement of data
quality. In the paper, some theoretical considerations on spatial data quality management will be presented first. The paper mostly
focus to present the recent approaches of quality control in Slovenian photogrammetric projects, e.g. aerial survey, scanning, aerial
triangulation, digital orthophoto maps, digital terrain model.
1. INTRODUCTION
The aim of photogrammetric projects is to collect spatial data
for topographic and cartographic databases, spatial/geographic
information systems, etc. Projects like aerial survey, aerial
triangulation, production of digital terrain model and digital
orthophoto maps are complex projects from many aspects.
Quality assurance and quality control are very important issues,
which encompass both quality of processes and quality of
products.
Why is there a concern for data quality? In the past, a
photogrammeter was a person skilled for dealing with
photogrammetric measurements. There was a traditional
knowledge of what quality data should be (e.g. acceptable
accuracy of relative and absolute orientation parameters,
knowledge of topographic data acquisition, etc).
Photogrammetric instruments were expensive and only big
enterprises, usually state institutions, could have afford them.
Nowadays, there are many low-cost photogrammetric systems
available in the market. Many private enterprises can purchase
photogrammetric analytical instruments or digital workstations,
but not always enough skilled photogrammetric personnel one
could find in the society. Generally, production of spatial data
by the private sector is increasing, where there are mostly no
required quality standards. In contrast, production of data by
national mapping agencies has long been required to conform to
national accuracy standards through mandated quality control.
In the past not enough attention was given to quality
management of spatial data in Slovenia. Digital data have been
collected on a mass scale while there was no final data quality
control. Collected data have thus only declarative quality. A
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financial detriment that is the result of bad data quality should
not be overlooked. In the last few years the situation has been
gradually improving, but there is sill no systematic approach to
quality of spatial data as well as not enough knowledge on this
topic in Slovenia. Introduction of quality control in some
photogrammetric projects (e.g. aerial survey, aerial
triangulation, digital orthophoto maps, DTM) significantly
yields to improvement of data quality, thus we are encouraged
to continue and to develop a general spatial data quality model.
2. THEORETICAL BACKGROUND OF QUALITY
MANAGEMENT
In general, the views of quality have changed revolutionarily in
the last hundred years. Prior to World War I, quality was
viewed predominantly as inspection, sorting out the good items
from the bad. Emphasis was on problem identification.
Following World War I and up to the early 1950s, emphasis
was still on sorting good items from bad (Kerzner, 1995).
However, quality control principles were now emerging in the
form of statistical and mathematical techniques, sampling tables
and process control charts. From the early 1950s to the late
1960s, quality control evolved into quality assurance, with its
emphasis on problem avoidance rather than problem detection.
Additional quality assurance principles emerged, such as the
cost of quality, zero-defect programs, reliability engineering
and total quality control. In the last decades there has been a
revolution toward improved quality. The improvements have
occurred not only in product quality, but also in quality
leadership and quality project management. Today, emphasis is
being placed on strategic quality management. Most
organizations today view quality more as a process than a
