For several decades single-component seismic reflection methods .._3_ by hcj


									GeoSciML: Enabling the Exchange of Geological Map Data
Bruce Simons                      Eric Boisvert                    Boyan Brodaric                     Simon Cox
GeoScience Victoria               Geological Survey of Canada      Geological Survey of Canada        CSIRO Exploration & Mining
GPO Box 4440 Melbourne,           490 rue de la Couronne,          615 Booth St, Ottawa,              ARRC, PO Box 1130, Bentley
Victoria, 3001, Australia         Québec, G1K 9A9 Canada           Ontario, K1A0E9 Canada             WA, 6102, Australia        

Tim R. Duffy                      Bruce R. Johnson                 John L. Laxton                     Steve Richard
British Geological Survey         U.S. Geological Survey           British Geological Survey          Geological Survey of Arizona
Murchison House, W Mains Rd       954 National Center              Murchison House, W Mains Rd        416 W. Congress St., #100
Edinburgh, EH9 3LA, UK            Reston, VA 20192, U.S.A.         Edinburgh, EH9 3LA, UK             Tucson, Arizona, 85701, USA                             

                                                                        develop a harmonised geoscience data model and exchange
                                                                        format based on GML (Geography Mark-up Language),
                        SUMMARY                                         referred to as GeoSciML (GeoScience Mark-up Language).
                                                                        These developments incorporate several novel aspects in
  The CGI data model working group have established an                  design of the data model and transfer format as well as the
  initial geology data model and XML based exchange                     technical procedures involved in their creation.
  language to accommodate geological map data, referred
  to as GeoSciML. The language is based on prior work                   Predecessor projects have strongly influenced the
  carried out at North American, European and Australian                development of GeoSciML.               These include multi-
  geological survey and research organisations. Unified                 jurisdictional activities by the North American Geologic Map
  Modelling Language (UML) has been used as a design                    Data Model Steering Committee (2004) and Australian
  aid for capturing the geological concepts and their                   Government Geologists Information Policy Advisory
  properties. The UML model has then been converted to                  Committee (2004), the CSIRO led eXploration and Mining
  the GML-conformant GeoSciML.                                          Mark-up Language (XMML) work (Cox, 2004) and individual
                                                                        agency work at the British Geological Survey (Sen and Duffy,
  The design of GeoSCiML meets the short-term goal of                   2005), GeoScience Victoria (Simons et al, 2005), and the
  accommodating the geoscience information presented on                 BRGM. Growing awareness of the overlap between these
  geological maps, as well as being fully extensible to                 projects and the desire to minimise duplication led to
  include the full range of geological concepts covered by              agreement on the formation of a working group to move
  the geosciences.      To demonstrate the ability of                   forward collaboratively on the development of a data model
  GeoSciML to deliver data via web feature services, a                  and transfer format under the auspices of the CGI.
  small subset has been selected as a testbed. This testbed
  will deliver lithostratigraphic units, boreholes, faults,             GeoSciML accommodates the short-term goal of representing
  contacts and compound materials from different national               geoscience information associated with geological maps and
  geological surveys.                                                   observations, as well as being extensible in the long-term to
                                                                        other geoscience data. It is unique in its breadth of inputs and
  Key words: data exchange, geology data modelling,                     content as it draws from many national geoscience data model
  GeoSciML, GML, Web Feature Services, XML.                             efforts. From these it establishes a common suite of feature
                                                                        types based on geological criteria (geological units, geological
                                                                        structures, fossils, geological relationships, earth materials,
                                                                        geological fabrics) or artefacts of geological investigations
                                                                        (specimens,      sections,    observations,     measurements).
The exchange of geoscientific information has traditionally
                                                                        Supporting objects, such as timescales and lexicons, are also
been through hard copy media such as geological maps,
                                                                        included so that they can be used as classifiers for the primary
reports and papers. The content and style of geological maps
has often been left to the authors' or organisations' individual
preferences or standards, with the success of the information
                                                                        The demonstration of the delivery of a subset of GeoSciML
transfer dependent on the skills of the user to 'interpret' the
                                                                        via Web Mapping Services (WMS) and Web Feature Services
intent of the mapmaker. With the development of web-based
                                                                        (WFS) has been undertaken by the CGI working group. This
data access interfaces, and increased requirements for
                                                                        'testbed' delivers an extensive suite of property information for
machine-based data exchange by geoscientific agencies, the
                                                                        lithostratigraphic and lithodemic geological units, faults,
ability to interpret meaning is lost. Although standardised
                                                                        geological contacts and boreholes.
formats for geoscience data have long been seen as a desirable
goal, the need for common models and encodings has assumed
a greater practical significance for this machine-based data                           METHOD AND RESULTS
                                                                        The specific objectives of the CGI working group are to:
The IUGS Commission for the Management and Application                      develop a conceptual model of geoscientific information
of Geoscience Information (CGI) established an initiative to               drawing on existing data models;

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GeoSciML                        Simons BA, Boisvert E, Brodaric B, Cox S, Duffy TR, Johnson BR, Laxton JL and Richard S

    implement an agreed subset of this model in an agreed            base map depiction and extents to draw a geologic map
    schema language;                                                  visualisation.
    implement an XML/GML encoding of the model subset;            6. GeologicObject represents those geological concepts that
    develop a testbed to illustrate the potential of the data        can be described in their own right and may be properties
    model for interchange;                                            of other geological concepts, but are not mappable
    identify areas that require standardised classifications in      features. Rocks (which are considered as types of
    order to enable interchange;                                      CompoundMaterials) and fossils are two such objects.

Standards                                                          A sample of the associations, and their roles, that exist
                                                                   between various classes are shown in the summary diagram
In order to benefit from emerging geospatial web-service           (Figure 1) to illustrate the way that the model works. For
standards the focus is on GML-based XML data encodings for         example a Fault can be made up of FaultSurfaces (role =
the transfer format. The modelling framework used for              faultSurface) that may have one or more Displacement
GeoSciML is based primarily on the Rules for Application           attributes.
Schema from ISO/TC 211 (ISO 19109:2004). The rules assert
that geospatial information languages should be developed
and governed within domain-specific communities. They also
specify the term "feature" for a real-world object of interest.
Features are classified into types on the basis of a
characteristic set of properties. For example a "GeologicUnit"
is a feature type that has a rank, composition, morphology,
outcrop character, colour, etc.

Complementing the ISO standards, GML has been developed
as an XML encoding for geographic information. GML
directly provides few concrete feature types, as these are
intended to be created using the standard components in a
domain-specific "GML Application Schema". GeoSciML is
an example of one of these schema.

Cox et al. (2004) established rules for converting models
expressed in UML to GML-conformant XML. These rules are
highly significant since they allow GML-compatible model
development to take place in the intuitive graphical UML
environment. They also ensure consistency of XML schema
derived from the UML.

The GeoSciML Model

Figure 1 shows a UML diagram of a summary version of
GeoSciML to illustrate the framework within which the data
model is being developed. Due to the complexity of the
model we have not shown all the classes. The attributes of the
various classes are also not shown.

Four top-level GML classes are used as starting points:
1. Abstract Feature is the root of all classes representing
    real-world objects. These include GeologicFeatures,            Figure 2. UML diagram of GeoSciML GeologicUnit and
    representing geological concepts (GeologicStructures,          EarthMaterial classes, showing inheritance, associations
    GeologicUnits), as well as artefacts of the evidence           and roles, and class attributes, with data types and
    collection process (Site, Observation etc) and artefacts of    cardinality.
    the geologic record (MappedFeatures).
2. Abstract Geometry is the GML object that describes the          The properties of geological units are shown in Figure 2.
    geometry of the features (eg. point, line, polygon).           These are the subset of properties that have been chosen for
3. Metadata is the root of all classes dealing with metadata,      testbed purposes. Like all classes in GeoSciML, geological
    including dataset metadata, mapped feature metadata and        units (GeologicUnit) inherit a name, description and GML id
    geological feature metadata.                                   from AbstractGML. They also inherit an age and purpose
4. Definition is the root of classes representing the reference    from GeologicFeature, in addition to the GeologicUnit
    systems, controlled vocabularies and dictionaries that         attributes bodyMorphology, outcropCharacter, genesis and
    constrain the values of the class properties.                  exposureColour. Only lithostratigraphic and lithodemic units
Two additional classes specific to GeoSciML inherit directly       (types of LithologicUnits) are being considered as part of
from the top level AbstractGML class:                              testbed. Lithologic units have the additional attributes of
5. GeologicPortrayal stores the model elements used to             rank, composition, weatheringCharacter, the presence of
    represent the selection and symbolization of                   structures and metamorphicGrade. Lithostratigraphic units
    MappedFeature AbstractGeometry instances, along with           include additional attributes to account for specific bedding

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GeoSciML                        Simons BA, Boisvert E, Brodaric B, Cox S, Duffy TR, Johnson BR, Laxton JL and Richard S

related properties. Other types of GeologicUnits (such as          seek broader geological community support for GeoSciML as
Chronostratigraphic, Geomorphologic, Pedostratigraphic,            the standard geological map data exchange language.
Lithotectonic) are accommodated by the model.           The
GeologicUnitPart class allows GeologicUnits to be made up of       Controlled Vocabularies
other GeologicUnits (for example 'Formations' with child
'Members'). The CompositionPart class allows GeologicUnits         GeoSciML is designed to provide the mechanism that will
to be composed of CompoundMaterials, which in the model            enable delivery of the geological and geographic information
represent either rocks or unconsolidated material.                 associated with geological maps. A current gap in GeoSciML
                                                                   is the lack of an agreed set of vocabularies for the data
GeoSciML also includes an extensive suite of data types            content, limiting the ability to deliver standard data content.
defined to accommodate the wide range of values that are           Therefore, at present, GeoSciML provides a standard schema
assigned to geological observations. These are designed to         but does not define standard content within the schema.
accept single (eg fine grained) or range (eg fine grained to       Future work involves developing agreed standards on data
medium grained) values from controlled vocabularies, single        content, that is controlled vocabularies, thesaurus and
or range numeric measurements with error values and units of       dictionaries, by the international geological community. The
measures, or combinations of these.                                CGI are establishing a separate collaborative effort to meet
                                                                   this need.
Testbed 2
The working group has established a testbed to demonstrate
the delivery of geological map data via the web using Web          GeoSciML accommodates the short-term goal of representing
Mapping Services (WMS), Web Feature Services (WFS) and             geoscience information associated with geological maps and
GeoSciML. This follows on from demonstrations using                observations, as well as being extensible in the long-term to
XMML to exchange borehole data between the British and             other geoscience data. It is unique in both the breadth of its
French geological surveys (see       inputs and content. This has been achieved by drawing on
twiki/bin/view/CGIModel/TestBed#CGI_Interoperability_Test          many local, national and international geoscience data model
bed_1) and the SEEGrid geochemistry demonstrator (Cox et           efforts, in conjunction with the work on international data
al., 2005). The aim of Testbed 2 is to evaluate the ability of     exchange standards.
GeoSciML to deliver the rich and complex data used to
generate geological maps from a variety of geological              The working group has established a testbed to demonstrate
organisations via WMS and WFS. The geological surveys of           the delivery of geological map data from a variety of national
Canada, USA, UK, Sweden, France and Arizona along with             and state geological surveys using Web Mapping Services,
Geoscience Australia, GeoScience Victoria and CSIRO are            Web Feature Services and GeoSciML. The success of this
participating in Testbed 2.                                        demonstrator will determine the future for XML-based
                                                                   geological data exchange languages.
Testbed 2 aims to deliver 4 use cases using GeoSciML:
    Use Case 1: Client asks for a map showing geological                                 REFERENCES
     units, faults, contacts and/or boreholes on a browser.
     Server returns a map with default symbolisation. User         Cox, S.J.D., 2004, XMML – a standards conformant XML
     can click on any graphic feature from one layer to            language for transfer of exploration data: Proceedings,
     retrieve at least an HTML presentation of the attributes of   ASEG/PESA Geophysical Conference and Exhibition, Sydney
     that feature which is consistent with the CGI model.          2004
     (Client can request other formats than HTML if server
     supports them.).                                              Cox, S.J.D., Daisey, P.W., Lake, R., Portele, C. and
                                                                   Whiteside, A., 2004, Geography Markup Language (GML)
    Use Case 2: Select mapped features by specifying a            3.1.0, OpenGIS® Recommendation Paper, OGC document
     geographic bounding box and download the most specific        03-105rl, xxi+ 580.
     information available for each mapped feature as
     GeoSciML                                                      Cox, S.J.D., Dent, A., Esterle, J., Woodcock, R., Girvan, S.,
                                                                   Mackey, T., Wyborn, L., Bandy, S., Ward, B., Hannant, T.,
    Use Case 3: The user chooses to display mapped features       Jenkins, G., Jolly, M., Atkinson, R. and Barrs, P., 2005
     representing geologic units, symbolized on the basis of       Standardized Web-access to Geoscience Datasets: the
     age using the IUGS standard geologic age colour scheme,       SEEGrid WFS Testbed. Proceedings of IAMG'05: GIS and
     or on the basis of lithology using a CGI defined lithology    Spatial Analysis, Vol.2, 844-849.
     colour scheme.
                                                                   Government Geologists Information Policy Advisory
    Use Case 4 (optional): Select a subset of geologic unit       Committee, 2004, National Geological Data Model Version
     mapped features on the basis of age or lithology and          1.0 Explanatory Notes.
     highlight them with the same highlight colour.      

Testbed 2 aims to deliver these four use-cases using geological    North American Geologic Map Data Model Steering
data from a variety of organisations and map-scales as a           Committee, 2004: NADM Conceptual Model 1.0—A
demonstration by September 2006. The testbed results will be       conceptual model for geologic map information: U.S.
formally presented to the CGI during the IAMG conference in        Geological Survey Open-File Report 2004-1334, 58 p.,
September 2006 with the intention to showcase the results to       accessed online at URL

AESC2006, Melbourne, Australia.                                                                                            3
GeoSciML                     Simons BA, Boisvert E, Brodaric B, Cox S, Duffy TR, Johnson BR, Laxton JL and Richard S

Also published as Geological Survey of Canada Open File        Simons, B., Ritchie, A., Bibby, L., Callaway, G., Welch , S.,
4737, 1 CD-ROM.                                                and Miller, B., 2005, Designing and Building an Object–
                                                               Relational Geoscientific Database using the North American
Sen, M. and Duffy, T., 2005 GeoSciML: Development of a         Conceptual Geology Map Data Model (NADM-C1) from an
generic GeoScience Markup Language. Computers &                Australian Perspective. Proceedings of IAMG'05: GIS and
Geosciences, 31, 1095–1103.                                    Spatial Analysis, Vol.2, 929–934.

Figure 1. UML diagram showing the primary hierarchy of a selection of GeoSciML classes and relationship to base classes
provided by GML, and a selection of associations between classes.

AESC2006, Melbourne, Australia.                                                                                        4

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