Díaz, P., Masó, J., Sevillano, E., Ninyerola, M., Zabala, A., Serral, I., Pons, X. (2012). Analysis of quality metadata in the GEOSS Clearinghouse. International Journal of Spatial Data Infrastructures Research. Vol 7 (2012), pp. 352-377.

1. Analysis of the
Quality Metadata in
GEOSS Clearinghouse
QUAlity aware VIsualisation for
the Global Earth Observation
system of systems
SEVILLANO Eva1, DÍAZ Paula2, NINYEROLA Miquel1,
MASÓ Joan2 , ZABALA Alaitz1, PONS Xavier1
1 UAB Universitat Autònoma de Barcelona.
2 CREAF Centre for Ecological Research and Forestry Applications.

2. Objectives
• To get a first analysis of the data quality in the
Clearinghouse
• Analyze the quality contained in the metadata (ISO 19115)
– Quality indicators
www.geoviqua.org
– Quality indicators
– Lineage
– Usage
• Start building components for the GEO Portal
– Quality Broker
– Quality searcher
– Quality visualization

3. Methodology
97203 XML
documents
CSW
GEOSS
Clearinghouse
www.geoviqua.org
• Harvest all XML documents,
ISO 19115. (October 2011)

4. Methodology
97203 XML
documents
Database
GestBD
Xpath
extraction
CSW
GEOSS
Clearinghouse
www.geoviqua.org
• Massive extraction of MD
quality elements
– Quality indicators
– Lineage
– Usage

5. Overall Results
• Total metadata records in the
Clearinghouse
– 97203
• Total number of quality
indicators
– 52187
www.geoviqua.org
– 52187
• Metadata records with quality
indicators
– 19107
• Metadata records with lineage
– 10899 (9261 process, 3771
source)
• Metadata with usage
– 1226

6. Quality Scope
• 19.66% Metadata records with quality indicators
– 2.7 quality indicator per metadata record
www.geoviqua.org

7. 1. Quality indicators
• 19.66% Metadata records with quality
www.geoviqua.org

8. Quality indicators
• 19.66% Metadata records with quality
– 2.7 QI/MD
www.geoviqua.org

9. Quality indicators
www.geoviqua.org

10. Quality Indicators in IDEC Metadata
Quality indicators – Comparison
Clearinghouse - IDEC
www.geoviqua.org
Positional
Accuracy
95.38%
Thematic
Accuracy
2.60%
Completeness
0.46%
Temporal
Accuracy
0.06%
Logical
Consistency
0.02%
Quality Indicators in IDEC Metadata
GEOSS
IDEC

11. Quality indicator result
85.8%
(22275 QI)
14.18%
(3669 QI
mainly conformance to INSPIRE)
www.geoviqua.org
0.02%
(5 QI)
19115-2 Extension
for "per pixel"
quality

12. Quality indicator result
www.geoviqua.org

13. Quality indicators - Quantitative
10000
12000
14000
16000
18000
Numberofqualityelements
Quality elements - Quantitative measures
www.geoviqua.org
0
2000
4000
6000
8000
10000
Numberofqualityelements
Complete value
Declarevalue
Quantitativetype

14. Quality indicators - Qualitative
600
800
1000
1200
1400
Numberofqualityelements
Quality elements - Conformance measures
www.geoviqua.org
0
200
400
600
Numberofqualityelements
Conformance to specification
Declare conformance
Conformance type

15. Coverage result
(ISO19115-2 extension)
• Clearinghouse record ID: 273234, 273232, 273233, 273235, 273236)
• Only 5 records use this. Bad news for visualizing data + quality maps
• Title: OMNO2e:OMI Column Amount NO2:ColumnAmountNO2CS30
<gmd:DQ_QuantitativeAttributeAccuracy>
<gmd:measureDescription>
<gco:CharacterString>The 'version 003' product is the second public release. It is based on improved
radiance calibration. For details, please see document:
www.geoviqua.org
radiance calibration. For details, please see document:
http://disc.sci.gsfc.nasa.gov/Aura/OMI/OMTO3e_v003.shtml</gco:CharacterString>
</gmd:measureDescription>
<gmd:result><gmi:QE_CoverageResult>
<gmi:spatialRepresentationType><gmd:MD_SpatialRepresentationTypeCode
codeList="./resources/codeList.xml#MD_SpatialRepresentationTypeCode"
codeListValue="grid">grid</gmd:MD_SpatialRepresentationTypeCode></gmi:spatialRepresentationType>
<gmi:resultFile gco:nilReason="missing" />
<gmi:resultFormat>
<gmd:MD_Format>
<gmd:name><gco:CharacterString>CF-netCDF</gco:CharacterString></gmd:name>
</gmd:MD_Format>
</gmi:resultFormat>
</gmi:QE_CoverageResult></gmd:result>
</gmd:DQ_QuantitativeAttributeAccuracy>

16. 2. Lineage
www.geoviqua.org

17. 2. Lineage
www.geoviqua.org

18. 2. Lineage
www.geoviqua.org

19. LI_ProcessStep with LI_Source
Example
Clearinghouse record ID 131007 (simplified)
• Compile survey input data from the best and most current survey records.
– BLM database of the index to all official (microfilm, CD, other) BLM survey records.
– USFS survey records.
– Private land surveyor records
– GCDB Data Collection Attribute Definitions Version 2.0, Appendix A, 2/14/1991. Survey records
used - source abbreviations.
• Compile listings of known locations of PLSS corners.
– USGS topographic quadrangles and other sources.
– USC&amp;GS published coordinate data.
– NGS published coordinate data.
– BLM global positioning Data.
– USFS global positioning data.
• Coordinates of control stations are entered into a control data base with associated
reliabilities.
• Topologically correct GIS coverages are modified to use FGDC compliant naming
www.geoviqua.org
• Topologically correct GIS coverages are modified to use FGDC compliant naming
conventions and then loaded into the LSI database. These layers can then be
downloaded as shapefiles through the LSI website.
• GCDB Data was downloaded for Kiowa and Cheyenne Counties, Colorado.
– C:fgis_datasandzippedkiowatwnshp.shp.xml
• Metadata imported and data was exported from regions format to shapefile format
• Dataset copied.
– C:fgis_datasanddatabasedataplssck_gcdb_region_township
• Source Contribution: Survey data in the form of official (microfilm, CD, other) survey
and BLM, abstracted into a vector digital format.online
• Source Contribution: Survey and control data from the Cartographic Feature File
(CFF) data set.disc
• Source Contribution: Digitized control data from standard topological quadrangle
sheets.disc

20. LI_Lineage: LI_Source
• 6.02% metadata records (5851)
contain direct list of the data
sources.
– 1.85% (1798) with temporal extent
class LI_Source_only
LI_Lineage
+ statement :CharacterString [0..1]
+ scope :DQ_Scope [0..*]
constraints
{"source" role is mandatory if LI_Lineage.statement
and "processStep" role are not documented}
Metadata Information::MD_Metadata
+resourceLineage
0..*
www.geoviqua.org
• Gives credit (attribution, and
eventually some trust on them)
• If quality indicators are not
provided for the dataset, the
quality indicators from sources
can be a clue.
LI_Source
+ description :CharacterString [0..1]
+ sourceSpatialResolution :MD_Resolution [0..1]
+ sourceReferenceSystem :MD_ReferenceSystem [0..1]
+ sourceCitation :CI_Citation [0..1]
+ sourceMetadata :CI_Citation [0..*]
+ scope :DQ_Scope [0..*]
constraints
{"description" is mandatory if "scope" is not documented}
{"scope" is mandatory if "description" is not documented}
and "processStep" role are not documented}
{"processStep" role is mandatory if
LI_Lineage.statement and "source" role are not
documented}
+source 0..*

21. LI_Lineage: LI_ProcessStep
• 8.26% metadata records
(8035) contain the direct
list of the processes
without sources
– 292 (0.30%) contain date
class From_LI_ProcessStep_to_LI_Source
LI_Lineage
+ statement :CharacterString [0..1]
+ scope :DQ_Scope [0..*]
constraints
Metadata Information::MD_Metadata
+resourceLineage0..*
www.geoviqua.org
• With the order of these
processes.
• If quality indicators are not
provided for the dataset, it’s
difficult to infer resource
quality with only a process
list
LI_ProcessStep
+ description :CharacterString
+ rationale :CharacterString [0..1]
+ stepDateTime :TM_Primitive [0..*]
+ processor :CI_ResponsiblePartyInfo [0..*]
+ reference :CI_Citation [0..*]
+ scope :DQ_Scope [0..*]
constraints
{"source" role is mandatory if LI_Lineage.statement
and "processStep" role are not documented}
{"processStep" role is mandatory if
LI_Lineage.statement and "source" role are not
documented}
+processStep 0..*

22. Complete Provenance:
MD_ProcessStep with MD_Source
• 1.26% metadata
records (1226 ) with
more complete
provenance process .
• How and when the data
sources where used
class From_LI_ProcessStep_to_LI_Source
LI_Lineage
+ statement :CharacterString [0..1]
+ scope :DQ_Scope [0..*]
constraints
{"source" role is mandatory if LI_Lineage.statement
and "processStep" role are not documented}
Metadata Information::MD_Metadata
+resourceLineage0..*
www.geoviqua.org
sources where used
• If quality indicators are
not provided for the
dataset, we can
deduce which sources
have more influence in
the quality of the final
result
LI_Source
+ description :CharacterString [0..1]
+ sourceSpatialResolution :MD_Resolution [0..1]
+ sourceReferenceSystem :MD_ReferenceSystem [0..1]
+ sourceCitation :CI_Citation [0..1]
+ sourceMetadata :CI_Citation [0..*]
+ scope :DQ_Scope [0..*]
constraints
{"description" is mandatory if "scope" is not documented}
{"scope" is mandatory if "description" is not documented}
LI_ProcessStep
+ description :CharacterString
+ rationale :CharacterString [0..1]
+ stepDateTime :TM_Primitive [0..*]
+ processor :CI_ResponsiblePartyInfo [0..*]
+ reference :CI_Citation [0..*]
+ scope :DQ_Scope [0..*]
and "processStep" role are not documented}
{"processStep" role is mandatory if
LI_Lineage.statement and "source" role are not
documented}
+processStep 0..*
+source
0..*

23. Complete provenance in ISO19115-2
• LI_ProcessStep includes a
LE_Processing that has a
runTimeParameters attribute that
allows us describing the exact list of
parameters used in the execution.
• There is a citation of the algorithm
used (LI_Algorithm).
class From_LE_ProcessStep_to_LE_Source
LI_Source
+ description :CharacterString [0..1]
+ sourceSpatialResolution :MD_Resolution [0..1]
+ sourceReferenceSystem :MD_ReferenceSystem [0..1]
+ sourceCitation :CI_Citation [0..1]
+ sourceMetadata :CI_Citation [0..*]
+ scope :DQ_Scope [0..*]
constraints
{"description" is mandatory if "scope" is not documented}
{"scope" is mandatory if "description" is not documented}
LI_ProcessStep
+ description :CharacterString
+ rationale :CharacterString [0..1]
+ stepDateTime :TM_Primitive [0..*]
+ processor :CI_ResponsiblePartyInfo [0..*]
+ reference :CI_Citation [0..*]
+ scope :DQ_Scope [0..*]
LI_Lineage
+ statement :CharacterString [0..1]
+ scope :DQ_Scope [0..*]
constraints
{"source" role is mandatory if LI_Lineage.statement
and "processStep" role are not documented}
{"processStep" role is mandatory if
LI_Lineage.statement and "source" role are not
documented}
Metadata Information::MD_Metadata
+processStep 0..*
+resourceLineage
0..*
www.geoviqua.org
used (LI_Algorithm).
• All these extensions were done for
the benefit of the EO gridded data,
but there are not in the
Clearinghouse.
• We can completely evaluate the
quality of the resulting product if we
know the uncertainties that sources
have in their metadata
(sourceMetadata citation in
LI_Source).
From ISO 19115-2:2009 shown for informative purposes only
Data quality information -
Imagery::
LE_ProcessStep
Data quality information - Imagery::
LE_ProcessStepReport
+ name :CharacterString
+ description :CharacterString [0..1]
+ fileType :CharacterString [0..1]
If "LE_NominalResolution.scanningResolution" is used
then "LE_Source.scaleDenominator" is required
Data quality information - Imagery::
LE_Source
+ processedLevel :MD_Identifier [0..1]
+ resolution :LE_NominalResolution [0..1]
Data quality information - Imagery::
LE_Processing
+ identifier :MD_Identifier
+ softwareReference :CI_Citation [0..1]
+ procedureDescription :CharacterString [0..1]
+ documentation :CI_Citation [0..*]
+ runTimeParameters :CharacterString [0..1]
Data quality information -
Imagery::LE_Algorithm
+ citation :CI_Citation
+ description :CharacterString
«Union»
Data quality information - Imagery::
LE_NominalResolution
+ scanningResolution :Distance
+ groundResolution :Distance
"description" is mandatory if
"sourceExtent" is not documented
"sourceExtent" is mandatory if
"description" is not documented
+report 0..*
+output
0..*
+processingInformation0..1
+algorithm 0..*

24. 3. Usage - User feedback
www.geoviqua.org
• There is one small entry for user
feedback in the current ISO-19115:
• MD_Usage
– Brief description of ways in which the
resource is currently or has been used

25. • There are 1.2% (1133) entries
– SpecificUsage and
– UserContactInfo, only
• All made by the same institution!:
MD_Usage - User feedback
www.geoviqua.org
– Landesvermessung und Geobasisinformation
Brandenburg (LGB)
– Tel +49-331-8844-123, Fax. +49-331-8844-16123
– Heinrich-Mann-Allee 103, Potsdam, Brandenburg 14473,
Deutschland
– kundenservice@geobasis-bb.de
– http://www.geobasis-bb.de

26. Conclusions
• There are many different kinds of quality indicators
– There is a lack of a complete description of values provided (no units, missing
measure name, missing evaluation method)
• Quality coverage results (by pixel) are almost inexistent and the the link is
not there
• Lineage information is rich in many records, some with more that 100
entries in source or ProcessSteps
www.geoviqua.org
entries in source or ProcessSteps
• We have usage examples -> Feedback
• Current data is enough to demonstrate search and visualization with
some limitations. Good for GeoViQua.
• Next steps:
– Assess the Quality of Quality Metadata?
– Extend this analysis to other capacity catalogues integrated in the EuroGEOSS
Broker

27. Thank you!
Danke!
Grazie!
Merci!
Ευχαριστίες!
Diolch!
Bedankt!
Köszönöm!
Ačiū!
Благодарам! Спасибі!Ευχαριστίες!
Vďaka!
Tak!
Díky!
Tänan!
Kiitos!
Благодарам!
Dzięki!
Mulţumiri!
Хвала!
Tack!
Teşekkürler!
Спасибі!
Спасибо!
Obrigado!
Takk!
Gràcies!
Gracias!
QUAlity aware VIsualisation for
the Global Earth Observation
system of systems