Data Harmonization - Principles© NERC All rights reserved Data Harmonization - Principles OneGeology-Europe Plus Workshop – Ljubljana 30/5/13 John Laxton

© NERC All rights reserved

Data Harmonization - Principles

OneGeology-Europe Plus Workshop – Ljubljana 30/5/13

John Laxton


Outline

• What is geological map harmonization?

• GeoSciML as a means of harmonization

• Scope of GeoSciML

• Overview of GeoSciML data model

• GeoSciML in OneGeology-Europe

• Overview of OneGeology-Europe

vocabularies


Map harmonization - paper

• Traditional paper geological maps:

• Generally lithostratigraphic

• Conform to common overall design

• Classify and describe rocks differently

• Different colour schemes

• Tile (map sheet) based – don’t necessarily join

up even within one series

• Different levels of semantic and spatial

resolution


Map harmonization - paper

Lack of

harmonization

across a

national border


Map harmonization - steps

• Semantic harmonisation

• Geometric harmonisation

• OneGeology Europe aimed to achieve complete semantic

harmonisation, but geometric harmonisation was only carried

out in limited trial areas


Map harmonization - digital

• Digital geological maps:

• Commonly part of a ‘seamless’ database, so edge

mismatches more visible

• Semantics held as attributes of geometric features

• Geometric mismatches

• Can be snapped/edited if small

• Large mismatches require geologist intervention and

possibly fieldwork (out of scope of OneGeology Europe)

• Semantic mismatches

• Require common means of describing features

• Common terms to be used to describe features



The reminder of this session will

focus on the requirements for

achieving semantic

harmonization, as this is the

principle focus

of OneGeology-Europe


There are four levels of harmonization:

Map harmonization - levels

GeoSciML

systems

syntax

schematic

semantic

interoperability

Geoscience

community

OpenGIS

community

(OGC)

Data content

Data structure

Data language

Data systems

1GE

Vocabularies


(www.GEONgrid.org)

Different schema

Different semantics




• Requirements:

• Shared schema

• a common conceptual data model so that features

on a geological map (eg geologic units) are

described using the same properties (eg age,

lithology etc)

• Shared semantics

• common vocabularies so that a particular property

(eg lithology) is described using the same

concepts (eg granite, sandstone etc)


• to develop a conceptual model of geoscientific

information drawing on existing data models

• to implement an agreed subset of this model in an

agreed schema language (UML)

• implement an XML/GML encoding of the model

subset

• identify areas that require standardised

classifications (vocabularies) in order to enable

interchange

GeoSciML - objectives


- <RockMaterial>

- <geneticCategory>

- <CGI_TermValue>

<value codeSpace="urn:cgi:classifierScheme:BGS:geneticCatTerms">METAMORPHIC</value>

</CGI_TermValue>

</geneticCategory>

- <consolidationDegree>

- <CGI_TermValue>

<value codeSpace="urn:cgi:classifierScheme:BGS:consolidationTerms">INDURATED</value>

</CGI_TermValue>

</consolidationDegree>

- <lithology>

- <ControlledConcept gml:id="RCS2">

<gml:name codeSpace=“http://www.cgi-iugs.org/uri">urn:cgi:classifier:BGS:RCS:METR</gml:name>

<identifier codeSpace="http://www.cgi-iugs.org/uri">urn:cgi:classifier:BGS:RCS:METR</identifier>

<name xml:lang="en" codeSpace="urn:cgi:classifierScheme:BGS:RCS">METAMORPHIC ROCK</name>

<vocabulary xlink:href="urn:cgi:classifierScheme:BGS:RCS" />

</ControlledConcept>

</lithology>

</RockMaterial>

standard

content

</RockMaterial>

standard

structure

GeoSciML

http://appgeosciml.brgm.fr/GeoSciMLWeb/












• common structure for geologic data sent via OGC web services

• (optional) common geologic data content: vocabularies and concept defs

GSC PostGIS

USGS ESRI

Etc.

WMS

WFS

WMS

WFS

WMS

WFS

USGS

schema

other

schema

GSC

schema

GeoSciML

GeoSciML


International collaboration for geologic data

interoperability

- International Union of Geological Sciences

- Commission for the Management and Application

of Geoscience Information

- Interoperability Working Group

GeoSciML – who is involved?


The main organisations involved in developing GeoSciML

were:

GA (Australia)

CSIRO (Australia)

VGS (Australia)

BRGM (France)

GSC (Canada)

SGU (Sweden)

USGS (USA)

AZGS (USA)

BGS (UK)

GSJ (Japan)

ISPRA (Italy)

GeoSciML – who is involved?


for information typically shown on geologic maps

- geologic units (the Dakota Sandstone)

- geologic structures (fault, fold, …)

- earth materials (sandstone)

- boreholes

- samples and measurements

application of int’l standards

- Geographic Information (ISO)

- Geography Markup Language (OGC)

- Observations & Measurements (OGC)

GeoSciML – scope


GeoSciML – versions

• OneGeology-Europe used GeoSciML v2.1

• The current version is GeoSciML v3.1

• Generally similar to GeoSciML v2.1 but some

significant differences, for example in the encoding of

geological age

• Currently developing GeoSciML v4 for submission as an

OGC standard. This mainly involves restructuring rather

than any significant differences in content

OneGeology-Europe Plus will use GeoSciML v2.1 for

consistency with OneGeology-Europe


GeoSciML – packages

• Geologic Feature (inc Mapped Feature)

• Geologic Unit

• Earth Material (lithology)

• Geologic Structure

• Fossil

• Geologic Age

• Boreholes & Observations

• Geologic Relation

• CGI Values

• Vocabulary

• Metadata

• Collection


Geological Feature


Geological Feature

A MappedFeature

is an occurrence (eg

on a map) of a

GeologicFeature –

it provides the

geometry (from

GM_Object)

1. A Geologic Feature can be a GeologicUnit or GeologicStructure.

2. One GeologicFeature can have several MappedFeature occurrences (eg for different scale maps, a 3D model etc)

3. A MappedFeature can only specify one GeologicFeature

The Sampling Frame

is the spatial reference

frame within which

the features have been

observed eg ground

surface, bedrock

surface etc


Geological Unit Geologic Unit

is a type of

Geologic

Feature and

inherits its

properties

The type of

Geologic Unit is

given by the

geologicUnitType

property

constrained by a

codelist

Age is described

in terms of

Geologic Events


Geological Event

A preferredAge is

mandatory in 1GE.

Optionally you can

also provide a

geologicHistory

1. A geologic age is the age of

some Geologic Event.

2. Each age is a range (upper

and lower) expressed in

terms of ICS

chronostratigraphic units

3. The eventProcess property

is mandatory and gives the

process (eg deposition)

given by the age

4. The eventEnvironment

property is optional and

gives the environment (eg

deltaic system) in which the

process operated


Composition Part The lithology of Geologic

Units is described using

Composition Parts. There

may just be one

Composition Part or

there may be several.


Composition Part

The lithology property is

constrained by a 1GE vocabulary

based on the CGI Simple Lithology

vocabulary.

The material property allows for

much more detailed description of

lithologies but is not used in 1GE

Role describes the role played by the

Composition Part in the Geologic Unit

as a whole, eg ‘lithosome’, ‘cyclic

bedding’ etc. If there is only one

Compostion Part the role should be set

to ‘only part’.

The proportion property indicates the

proportion of the Composition Part in

the Geologic Unit as a whole. It should

be described using vocabulary

constrained term values eg all,

predominant, subordinate.


Metamorphic Description

Metamorphic units can

optionally be described in 1GE

using the

MetamorphicDescription data

type


Metamorphic Description

1GE only uses the metamorphicFacies,

metamorphicGrade and protolithLithology

properties. These are all constrained by

vocabularies. All the properties are optional.


Geologic structure

Geologic Structures are

another type of Geologic

Feature

Geologic Structures can

therefore have their age

described by Geologic Event

Faults are a type of

Shear Displacement

Structure. The only

property required by

1G-E is faultType,

constrained by a

vocabulary of terms.

In 1G-E contacts are

only used to describe

linear features

delimiting impact

craters, calderas and

glacial stationary

lines. The only

property required by

1G-E is contactType .


Vocabularies (1)

• The CGI developed a suite of vocabularies for

use with GeoSciML

• These are designed for interoperability, rather

than being definitive for their domains

• CGI vocabularies generally have lower semantic

resolution than those used internally by data

providers

• There is generally a loss of information in

mapping to common vocabularies

• 1G-E used, or adapted, the CGI vocabularies


Vocabularies (2)

• The ICS chronostratigraphic units were used for age, with

some extra Pre-Cambrian units from Scandinavia added

• A vocabulary server allows the vocabularies to be browsed:

http://srvgeosciml.brgm.fr/eXist2010/brgm/client.html

• The 1G-E vocabularies use urn identifiers eg

urn:cgi:classifier:CGI:EventProcess:201001:weathering

• The current version of the CGI vocabularies use http:uri

identifiers:

http://resource.geosciml.org/classifier/cgi/eventprocess/0080

http://srvgeosciml.brgm.fr/eXist2010/brgm/client.html


Vocabularies

Select the 1G-E

20101 vocabulary

List of 1G-E

vocabularies

Hierarchy of terms

can be browsed

The urn identifier for

the term

Multi-lingual

translations for the

term

Definition of

the term


Questions?

Documents

Data Harmonization - Principles© NERC All rights reserved Data Harmonization - Principles OneGeology-Europe Plus Workshop – Ljubljana 30/5/13 John Laxton