2, 2012
r2000:Current
- in applied
rocesses, 19
i of Artificial
ge. Journal of
8): 1965-1969
International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences, Volume XXXIX-B2, 2012
XXII ISPRS Congress, 25 August - 01 September 2012, Melbourne, Australia
CONSISTENCY MATCHING IN THE INTEGRATION OF CONTOUR AND RIVER
DATA BY SPATIAL KNOWLEDGE
Tinghua Ai * , Min Yang
School of Resource and Environment Sciences,
Wuhan University,Wuhan 430072, China, tinghua_ai@tom.com
Commission II, WG II/4
KEY WORDS: Spatial data matching, Delaunay triangulation, Spatial data quality
ABSTRACT:
As the representation of terrain surface and height information, the contour data has the strict constraint relationship with the
distribution of river network. In spatial data integration and matching, the inconsistency usually occurs between the river network
and contour generating “river climbing uphill”. This study presents a method to build the matching relationship and to correct the
inconsistency between river network and contour data. Based on Delaunay triangulation, the terrain landform features are extracted
and by bend analysis build the matching relations between river network and contour. According to different inconsistency situations,
we offer two correction approaches depending on which data is precise, which includes the river network displacement referenced to
the contour and the opposite.
1. INTRODUCTION
After more and more spatial data infrastructures are completed,
the integration of heterogeneous data sources becomes an
important issue. In such fields as data update, interoperation
and dissimilation (via web), the integration of spatial data plays
a significant role not only to derive combined abstracted
information but also to extract differences between various data.
The up-to-date data is usually integrated to the existed database
to update the database. Different scale data are often integrated,
e.g. the large scale data to integrate and update small scale data
by map generalization. In geographic analysis, the integration of
spatial data is also an important process to prepare data since a
complex analysis usually involves multiple spatial data from
different sources and application domains which may have
different spatial reference systems, levels of accuracy, thematic
categoriess and other characteristics.
Database integration results in the matching question requiring
some works at the schema level and some works at the data
level, especially in the context of geographic data. The
inconsistency detection and adjustment is such an important
work when integrating and matching different data. During the
data integration, the data from different sources may contradict
to each other in geometric representation, topological
relationship or semantic description. The same object in the real
word may be represented in quite different ways, such as
geometric dimensions, abstraction levels, semantic hierarchies
and other properties. The data combination usually results in
conflict, e.g. the shallow polygon represented river meets the
collapsed axis represented river. The inconsistencies can occur
among both homogeneous feature and heterogeneous features.
For example, under the same hydrographic feature, the polygon
lake and the line river may be inconsistent; On the other hand,
the river feature may inconsistent with terrain data, e.g. contour
line.
The inconsistency results from different reasons, e.g. the
different representations (the river is represented by a shallow
polygon or a collapsed axis line), the database construction at
different time by different agencies, or the cognition from
different viewpoints. Correspondingly the data matching has to
be performed aiming at different data integration situations,
including the matching of (1) different scale data in same region,
(2) different semantic description under same environment, (3)
data from different domains, (4) associated data of different
features, and so on.
As logical consistency is one of five aspects of spatial data
quality (Goodchild 1991), to preserve the consistency becomes
an important maintenance in database construction. A few
methods have been developed to detect and adjust inconsistency
when data matching in the field of spatial data handling. Among
them the matching of different scale spatial data attracts more
interests to build the associations between less detailed data and
more detailed data (Dcvogele 1998, Walter 1999, Mustiere
2008, Birgit 2009, Revell 2009, Huh 2010). The road network
is especially an active feature in this domain (Mustiere 2008).
However, for the matching of heterogeneous features, namely
the matching of different features with some associations to
each other, such as contour and river data matching, road and
bridge matching, vegetation class and terrain level data
matching, there is few concerns on matching methods or
inconsistency detection. For associated heterogeneous features,
there exists some spatial distribution knowledge that can act as
matching rules. We can use this kind of spatial knowledge to
detect the inconsistency between the integrated data and further
by some methods corrects them to be consistent. The spatial
knowledge could be topological consistency, semantic
consistence and spatial association relationship supported by
geoscience, for example the first law of geography (Tobler
1965).
This study attempts to investigate the matching and integration
of contour and river data by spatial knowledge. The spatial
knowledge (constraint) used in the integration process concerns
the semantic relationship between contour and river distribution
that ‘river should flow into its talweg’. This implies for instance
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