objects of geologic map unit and make a guideline
about the specification of spatiotemporal ontology
model for digital geological map unit. Finally, we
construct the spatiotemporal retrieval system applied
geological ontology model.
2 THE SPECIFICATION OF
SPATIOTEMPORAL
ONTOLOGY MODEL FOR
GEOLOGICAL MAPS(DRAFT)
The specification of spatiotemporal ontology model
for geological maps limited to the scope of the
geological world to digital geological maps in
Korea, and extracted geological ages as time units
and rock units as spatial units. For the rock unit
ontology, we selected English-Korean lithological
terms found in digital geological maps and,
considering the standardization of terms, we
classified rock units, assigned classification
identifiers, and defined the concepts of terms.
2.1 Extraction of Spatiotemporal
Objects from Geological Maps
The classification of rock units of digital geological
maps aims at digitalization in lithologically uniform
minimum map unit. The classification of digital
geological map in the minimum unit divided space
into rock units and time into geological ages, and
extracted the objects of rock units and geological
ages existing in Korean digital geological maps.
First, objects existing in digital geological maps
were converted into the minimum units, and 1961
fields of rock layer names were mapped to the
specification of rock units ontology made through
this research. In addition, for standardizing terms in
object extraction, English and Korean terms were
sorted out and classified hierarchically. For making
the ontology specification, we structured the
conceptual definitions of terms, the hierarchical
structure of terms related to rocks and geological
ages, and the relation of inclusion.
Rock units of digital geological maps were classified
first into sedimentary rocks and sediments,
metamorphic rocks and igneous rocks, and then
subordinate classification was made for applicable
scopes. In addition, geological ages in digital
geological maps were classified first into the
Precambrian Eon and the Cambrian Eon, and then
subordinate classification was made for applicable
scopes.
In extracting spatiotemporal ontology objects from
geological maps, we analyzed Korean digital
geological maps in 1961 rock layer units and
organized them fittingly to the Korean system at the
level of undergraduate senior students, referring to
Introduction to Geology, Loren A. Raymond’s
Petrology, Geologic Map Unit Classification,
ver.6.1) of USGS, and GeMPeT (Geoscience,
Mineral, Petrology Thesaurus) in Australia.
2.2 Development of a Spatio Temporal
Ontology Model of Geological
Maps
We extracted geological unit objects for rocks and
geological ages from geological maps, and defined
and classified geological terms for the geological
units. In addition, we formulated a rock-time unit
ontology model for the geological units. In this
study, a spatiotemporal ontology model means a
sophisticated model upgraded from data to
knowledge. The geological map ontology model can
be defined as a set of terms for expressing space
objects of rock units and time objects of geological
ages as well as the system of contents and structures.
In addition, it includes color and pattern symbols
mapped one-to-one to spatiotemporal objects.
In rock units classification, S, I and M were
assigned as the identifiers of sedimentary rocks and
sediments, igneous rocks, and metamorphic rocks,
respectively, and sub-class rocks followed the
identification information. Based on the basic
classification, a hierarchical classification system
was prepared. Geological age classification was
made, referring to the Korean geological time scale
(Geological Society of Korea) and geological
dictionaries, by extracting geological age objects of
primary, secondary and tertiary classification items,
and then quaternary classification was added in
consideration of international geological time scale
standard in the future (Figure1).
3 ONTOLOGIC DATABASE OF
GEOLOGICAL MAPS
The basic data used in the spatiotemporal database
of geological maps are digital topographical maps
and digital geological maps. (figure 2).
Maps were extracted administrative districts such as
counties, towns, villages and provinces in the form
of polygons and they were used as data, and from
digital geological maps was built a database using
the spatiotemporal ontology model. First, we
WEBIST 2008 - International Conference on Web Information Systems and Technologies
334