OSGeo - User contributions [en]

Data Quality

2010-10-27T14:48:40Z

New Member Nominations 2010

2010-10-22T19:05:12Z

Wiki-JoWalsh: dont mean to suggest jo isnt gentle just wanting not seem diminitive sigh

{| class="wikitable"
|-
!Name
!Notes
|-
|Steve Woodbridge
|
* Steve has long been a strong advocate and user of the open geospatial world of products. It would be hard to find someone who is more helpful and willing to help on any topic than Steve. From his early help on Mapserver until now, Steve has been a very active member and contributor in the geospatial community.
|-
|Jesse Eichar
|
* Jesse Eichar has been a long-time developer on the uDig open source desktop GIS, and has contributed important work to the GeoTools library. He is a constant presence on the uDig community list, helping new users and developers. He has participated in the FOSS4G conference over the years, giving talks and teaching workshops. He knows the open source geospatial world, and is a part of the larger community.
|-
|Alex Mandel
|
* Alex is an excessively active contributor to the numerous facets of OSGeo. You have likely seen him on one of the many OSGeo IRC channel he haunts, regularly offering advice to newbies, contributing to conversations and volunteering to take on tasks. I've seen him contribute significantly over the last couple of years to the core development of the OSGeo-Live project and the marketing committee. He also helps out of the System Administration Committee, acts as a representative at numerous trade fairs, helped found the Californian OSGeo chapter, helped develop numerous Geography academic courses which use a variety of FOSS applications and he has contributed directly to QGIS. Alex brings a valuable "user perspective" with him, as he has a degree in Wildlife Biology and field experience with State and Federal agencies.
|-
|Hirofumi Hayashi
|
* He is one of the most active member of OSGeo-Japan Local Chapter and is deeply involved in promoting OSGeo in Japan and elsewhere. He is a great team player and also contributed significantly to Internationalization of OSGeo software, localization of documentation, enhancement to OSGeo4W package and organization of FOSS4G events in Japan. He is the Vice-Representative of OSGeo Japan Local Chapter and PSC member in the ZOO project. He bears all the positive attributes desired of a OSGeo Charter Member
|-
|Gavin Fleming
|
* Gavin is the chief organizer of FOSS4G 2008. I attended the FOSS4G2008 conference, which Gavin was instrumental in organising. He and his team attracted delegates from some 50 countries, and subsequently produced a hugely successful conference. This is a tribute to Gavin's exceptional hard work and dedication to the task at hand. In so doing, he managed to put South Africa firmly onto the FOSS4G map. I particularly appreciated his kind manner, for regardless of the pressures on him, he always treated people with dignity and respect.
|-
|Suchith Anand
|
* Suchith is the chief organizer of OSGIS UK 2009 and 2010, as an OSGeo charter member. Suchith has done a major service to the interests of our foundation by organizing OSGIS UK conferences and by setting up an open source geospatial lab at University of Nottingham and negotiating a MoU with OSGeo, I think he definitely should be a charter member.
|-
|Dr. Xianfeng Song
|
* Dr. Xianfeng Song, Associate Professor, Graduate University of Chinese Academy of Sciences, for his contributions to the FOSS4G2010 as a academic chair and also his great activities in OSGeo China and Japan chapters to involve international collaborations.
|-
|Milena Nowotarska
|
* [[Milena_Nowotarska]] is very active member of Poland OSGeo Chapter. She is the key person in localization of Quantum GIS, GRASS, gvSIG and author of first polish QGIS manual. Milena has been involved in translations of GUI, manuals, brochures and promotional materials. Co-founder of polish forum and wiki for mentioned projects and GRASS-wiki manager. Trainer and teacher of FOSS4G at university and during several workshops. Milena plays important role in popularization of FOSS in local governmental agencies in Poland. Co-organizer of upcoming QGIS Hackfest in Wroclaw 2010.
|-
|Hirofumi Hayashi
|
* Mr. Hayashi is one of the most active member of OSGeo-Japan Local Chapter and is deeply involved in promoting OSGeo in Japan and elsewhere. He is a great team player and also contributed significantly to Internationalization of OSGeo software, localization of documentation, enhancement to OSGeo4W package and organization of FOSS4G events in Japan. He is the Vice-Representative of OSGeo Japan Local Chapter and PSC member in the ZOO project. He bears all the positive attributes desired of a OSGeo Charter Member.
|-
|Bruce Bannerman
|
* Bruce has been very hard working toward the OSGeo cause and often provides valuable insights to OSGeo discussions from a government purchasing perspective. He currently works as the key a GeoSpatial Architect at the Australian Bureau of Meteorology, where he plays a key role in international programs such as the Global Earth Observation System of Systems http://www.earthobservations.org/ . Bruce was incredibly hard working on the FOSS4G 2009 organising committee, and was key in fostering OSGeo/OGC relationships by coordination and sourcing substantial sponsorship for the Climate Change Integration Plugfest. He has done a lot of local OSGeo evangelism, manning OSGeo booths at conferences, writing papers for Government committees on behalf of OSGeo and helping found and run the Australian/New Zealand local chapter of OSGeo.
|-
|Nicolas Bozon
|
* Nicolas Bozon is specialized in design and GUIs for FOSS4G based applications, he has contributed to various FOSS4G projects and used OSGeo tools for scientific research projects. He actively promoted OSGeo during many trainings and workshops in France and participates actively in national and international conferences (OSGeo fr + jp + th, ...), giving talks and teaching workshops. Nicolas co-founded the ZOO Project (http://zoo-project.org/), is ZOO PSC member and important contributor.
|-
|Jo Cook
|
* Jo Cook is the patient leader of the UK OSGeo community. For years she has stuck with it, waiting for the world around her to catch up. Now she is providing a guiding hand to the flourishing OSGeo:UK chapter as its members put on conferences, masterclasses, training. Jo's notable FOSS4G presentations include "[http://2007.foss4g.org/presentations/view.php?abstract_id=81| Portable GIS - GIS on a USB stick]" in 2007 and "[http://2010.foss4g.org/presentations_show.php?id=3595| Open source archaeology - two years later]" in 2010. One reason i am nominating Jo is that i think she'd make a good board member for the OSGeo foundation. I was surprised to learn that Jo's not already an OSGeo charter member.
|}
[[Category:Elections]]
[[Category:Election 2010]]

New Member Nominations 2010

2010-10-22T19:02:29Z

Wiki-JoWalsh:

{| class="wikitable"
|-
!Name
!Notes
|-
|Steve Woodbridge
|
* Steve has long been a strong advocate and user of the open geospatial world of products. It would be hard to find someone who is more helpful and willing to help on any topic than Steve. From his early help on Mapserver until now, Steve has been a very active member and contributor in the geospatial community.
|-
|Jesse Eichar
|
* Jesse Eichar has been a long-time developer on the uDig open source desktop GIS, and has contributed important work to the GeoTools library. He is a constant presence on the uDig community list, helping new users and developers. He has participated in the FOSS4G conference over the years, giving talks and teaching workshops. He knows the open source geospatial world, and is a part of the larger community.
|-
|Alex Mandel
|
* Alex is an excessively active contributor to the numerous facets of OSGeo. You have likely seen him on one of the many OSGeo IRC channel he haunts, regularly offering advice to newbies, contributing to conversations and volunteering to take on tasks. I've seen him contribute significantly over the last couple of years to the core development of the OSGeo-Live project and the marketing committee. He also helps out of the System Administration Committee, acts as a representative at numerous trade fairs, helped found the Californian OSGeo chapter, helped develop numerous Geography academic courses which use a variety of FOSS applications and he has contributed directly to QGIS. Alex brings a valuable "user perspective" with him, as he has a degree in Wildlife Biology and field experience with State and Federal agencies.
|-
|Hirofumi Hayashi
|
* He is one of the most active member of OSGeo-Japan Local Chapter and is deeply involved in promoting OSGeo in Japan and elsewhere. He is a great team player and also contributed significantly to Internationalization of OSGeo software, localization of documentation, enhancement to OSGeo4W package and organization of FOSS4G events in Japan. He is the Vice-Representative of OSGeo Japan Local Chapter and PSC member in the ZOO project. He bears all the positive attributes desired of a OSGeo Charter Member
|-
|Gavin Fleming
|
* Gavin is the chief organizer of FOSS4G 2008. I attended the FOSS4G2008 conference, which Gavin was instrumental in organising. He and his team attracted delegates from some 50 countries, and subsequently produced a hugely successful conference. This is a tribute to Gavin's exceptional hard work and dedication to the task at hand. In so doing, he managed to put South Africa firmly onto the FOSS4G map. I particularly appreciated his kind manner, for regardless of the pressures on him, he always treated people with dignity and respect.
|-
|Suchith Anand
|
* Suchith is the chief organizer of OSGIS UK 2009 and 2010, as an OSGeo charter member. Suchith has done a major service to the interests of our foundation by organizing OSGIS UK conferences and by setting up an open source geospatial lab at University of Nottingham and negotiating a MoU with OSGeo, I think he definitely should be a charter member.
|-
|Dr. Xianfeng Song
|
* Dr. Xianfeng Song, Associate Professor, Graduate University of Chinese Academy of Sciences, for his contributions to the FOSS4G2010 as a academic chair and also his great activities in OSGeo China and Japan chapters to involve international collaborations.
|-
|Milena Nowotarska
|
* [[Milena_Nowotarska]] is very active member of Poland OSGeo Chapter. She is the key person in localization of Quantum GIS, GRASS, gvSIG and author of first polish QGIS manual. Milena has been involved in translations of GUI, manuals, brochures and promotional materials. Co-founder of polish forum and wiki for mentioned projects and GRASS-wiki manager. Trainer and teacher of FOSS4G at university and during several workshops. Milena plays important role in popularization of FOSS in local governmental agencies in Poland. Co-organizer of upcoming QGIS Hackfest in Wroclaw 2010.
|-
|Hirofumi Hayashi
|
* Mr. Hayashi is one of the most active member of OSGeo-Japan Local Chapter and is deeply involved in promoting OSGeo in Japan and elsewhere. He is a great team player and also contributed significantly to Internationalization of OSGeo software, localization of documentation, enhancement to OSGeo4W package and organization of FOSS4G events in Japan. He is the Vice-Representative of OSGeo Japan Local Chapter and PSC member in the ZOO project. He bears all the positive attributes desired of a OSGeo Charter Member.
|-
|Bruce Bannerman
|
* Bruce has been very hard working toward the OSGeo cause and often provides valuable insights to OSGeo discussions from a government purchasing perspective. He currently works as the key a GeoSpatial Architect at the Australian Bureau of Meteorology, where he plays a key role in international programs such as the Global Earth Observation System of Systems http://www.earthobservations.org/ . Bruce was incredibly hard working on the FOSS4G 2009 organising committee, and was key in fostering OSGeo/OGC relationships by coordination and sourcing substantial sponsorship for the Climate Change Integration Plugfest. He has done a lot of local OSGeo evangelism, manning OSGeo booths at conferences, writing papers for Government committees on behalf of OSGeo and helping found and run the Australian/New Zealand local chapter of OSGeo.
|-
|Nicolas Bozon
|
* Nicolas Bozon is specialized in design and GUIs for FOSS4G based applications, he has contributed to various FOSS4G projects and used OSGeo tools for scientific research projects. He actively promoted OSGeo during many trainings and workshops in France and participates actively in national and international conferences (OSGeo fr + jp + th, ...), giving talks and teaching workshops. Nicolas co-founded the ZOO Project (http://zoo-project.org/), is ZOO PSC member and important contributor.
|-
|Jo Cook
|
* Jo Cook is the patient leader of the UK OSGeo community. For years she has stuck with it, waiting for the world around her to catch up. Now she is providing a gentle guiding hand to the flourishing OSGeo:UK chapter as its members put on conferences, masterclasses, training. Jo's notable FOSS4G presentations include "[http://2007.foss4g.org/presentations/view.php?abstract_id=81| Portable GIS - GIS on a USB stick]" in 2007 and "[http://2010.foss4g.org/presentations_show.php?id=3595| Open source archaeology - two years later]" in 2010. One reason i am nominating Jo is that i think she'd make a good board member for the OSGeo foundation. I was surprised to learn that Jo's not already an OSGeo charter member.
|}
[[Category:Elections]]
[[Category:Election 2010]]

Data Quality

2010-10-21T15:34:21Z

Wiki-JoWalsh:

For now this page is to discuss a proposal for a short project (4-7 months) looking at data quality approaches to collaborative online sources of information.

Later we might make it into a proper page about data quality and its implications for software.

* Starting with Nothing

* Attestation

* Edit-time quality reporting

* ...

== Participants in this document / proposal ==

[[User:JoWalsh|Jo Walsh]]

Data Quality

2010-10-21T15:33:27Z

Wiki-JoWalsh:

For now this page is to discuss a proposal for a short project (4-7 months) looking at data quality approaches to collaborative online sources of information.

Later we might make it into a proper page about data quality and its implications for software.

* Starting with Nothing

* Attestation

* Edit-time QA

* ...

== Participants ==

[[User:JoWalsh|Jo Walsh]]

Data Quality

2010-10-21T15:32:14Z

Wiki-JoWalsh:

2010-07-19T14:25:22Z

Wiki-JoWalsh:

2008-09-11T09:23:53Z

Wiki-JoWalsh: /* 4. Adaptable Ontology */

= Why DCLite4G =

The following points are set out to help answer the questions:

* Several geospatial metadata standards already exist, right? Is DCLite4G a new one?
* On what basis are properties of geographic data included in DCLite4G?
* How will the use of DCLite4G benefit me as a data provider?

== Background ==

The best known metadata standards are the international ISO19115:2003 standard describing Metadata for Geographic Information and the Federal Geographic Data Committee Common Core (hereafter FGDC) guidelines for metadata. At time of writing (April/May 2007) there is an effort to replace the FGDC standard with a North American (US, Canada) specific profile of ISO19915.

However, ISO19115 makes no attempt to describe geospatial web services provide protocol and access specific for data published online. Web Services are described by a separate standard, ISO19119. Nor does ISO19115 offer any recommended format for serialising metadata in order to share it - this is covered by another separate standard, ISO19139. The format is verbose and not common in use, and the full ISO19115 model mandates the inclusion of many properties which are not much use in finding data or in managing it.

Many national Spatial Data Infrastructure initiatives take the approach of recommending, for publication of metadata about geospatial information resources, a profile or subset of ISO19115.

Within the US the FGDC metadata standard is in common use. FGDC is a profile, not a format, for metadata - there is XML schema associated with it but the most common expression of FGDC metadata is in a tab-delimited format.

On the other hand, there is Dublin Core - a generic vocabulary for metadata about all kinds of (electronic) documents and data, common in library science and in a broader information retrieval community. Specifications and standards documents often offer a mapping of geodata properties to Dublin Core.

Given all this, why then seek to define a "new" model for metadata? DCLite4G represents for those who have worked on it, the "simplest useful thing"; a common core that is found within all the existing metadata standards and inside many different software packages.

The minimal model represents an overlap of the FGDC and ISO19115 standard. It corresponds closely to the minimal model proposed in the draft Implementing Rules for Metadata describing spatial data infrastructure capacity as mandated by the INSPIRE Directive.

It is not an intention to prescribe an XML format but to illustrate a model which can be represented using any of the common metadata standard representations. Samples are offered of DCLite4G being used as a 'mix-in' vocabulary in Atom and RDF feeds. One could use DCLite4G to define properties used in an ebRIM description.

An aim is to integrate systems rather than to require certain standards.
A common subset of well-known standards for geographic metadata is identified, building on common work in the open source geospatial community. This subset corresponds closely to the draft abstract model described by the Implementing Rules for Metadata in the INSPIRE European SDI. However, more emphasis is placed on machine-readable and repeatable properties of data: unique identifiers which can be used to annotate the provenance and processing history of data sets; URLs to represent license constraints; contact details for people responsible for data sets. The minimal model can be rendered as ISO19115/19139, FGDC, RDF, a Dublin Core Application Profile, GeoRSS/Atom, in KML Metadata: presenting as flexible a face to third party search services as possible.<

== 1. Making the minimum mandatory ==

It is better to get some metadata than none. There is a baseline necessary for a repository to do its work, manage rights and publish data useful to clients; this is what DCLite4G was originally designed to provide. The emphasis is on what is needed to rediscover and reuse the data.

== 2. Focusing on online resources ==

One reason for complexity in the ISO19115 and FGDC standards is the need to describe legacy, non-computer-based systems of spatial information and maps using the same standard. Separate standards appear to describe information available via web services or modern internet protocols. Meanwhile the documenting and cataloguing of simple use cases, of files and OGC standard web services publishing geographic information, is neglected because of a complexity bar to casual implmentation of the standard. A focus on online resources, and a focus on data and describing it, not on describing metadata and filling it out.

== 3. Machine Reusability ==

Emphasis on: nique identifiers which can be used to annotate the provenance and processing history of data sets; URLs to represent license constraints; URLs to represent classification schemes where provided, not references to code lists; contact details for people responsible for data sets.

== 4. Adaptable Ontology ==

Taxonomy and ontology are left very open. The use of URI schemes for keywords is recommended. Data annotation distributed. The emphasis is not on how the data is described, but on how it is used.

What structured ontology is provided is kept very minimal - classes for data sets and series, and a few core properties of geospatial data additional to the common metadata properties contained in Dublin Core / Dublin Core Terms - [http://dclite4g.xmlns.com http://dclite4g.xmlns.com]

= History of DCLite4G =

DCLite4G came about at first from a discussion of minimal model necessary to manage a public [[Geodata Repository]] run by OSGeo. The original model was based on the FGDC Common Core standard for geospatial metadata and now overlaps with ISO19115. [[User:Sfkeller|Stefan Keller]] came across the model through online discussion and formalised the abstract model approach and the idea of presenting a Dublin Core Application Profile. [[User:JoWalsh|Jo Walsh]] collated the different wiki versions into the current [[DCLite4G]] model description.

= References =

* [UNSDI]
* [GSDI]
* Czech / Swiss / other national refs
* [INSPIRE] Draft Implementing Rules on Metadata
* [CGD] Commons of Geographic Data, White Paper on Metadata, Onsrud et al

DCLite4G

2008-09-11T09:21:58Z

Wiki-JoWalsh:

DCLite4G is short for "Dublin Core Lightweight Profile for Geospatial". It is a ''minimal information model for metadata about geospatial data''. DCLite4G consists of:

* an abstract information model
* an implementation reference exploiting common standard vocabularies - [http://dublincore.org/ Dublin Core], [http://georss.org GeoRSS].
* a [http://dclite4g.xmlns.com/ namespace] used to define extra properties needed to usefully specify the properties of geospatial data.

The dclite4g namespace URL, [http://dclite4g.xmlns.com/schema http://dclite4g.xmlns.com/schema] contains an OWL ontology showing the structure, providing where possible mappings to various metadata schemas.

= Information Model =

== Data Set ==

A Data Set is an abstract object. It corresponds to the ideal of a data set, independent of a physical form or an encoding in which it is being distributed. For example, "TIGER 2005" or "OpenStreetmap from 2007-04-20", or "SRTM" would be considered data sets.

A Data Set may be part of a Series comprising related items of geographic data.

An item of geographic information. Should have at least a title and a URI; ideally the URI is that of a resource where it is possible to access the information directly.

=== Properties ===
{|
|-
| '''Title''' || A name given to a data set. Does not have to be unique or "canonical".
|-
| '''Abstract''' || A text description of the contents of a data set, remarks on anything interesting contained therein.
|-
| '''Keywords''' || A layer may have none or many keywords associated with it.
|-
| '''Series''' || Indicates a Series to which a data set may belong. (see below)
|-
| '''Publisher''' || Contact information for the Agent publishing the data set
|-
| '''Originator''' || Contact information for the original creator of the data set
|-
| '''Publication Date''' || Date on which the data was made available
|-
| '''License''' || URL of a data license whose terms cover the distribution of this data set, OR a text string describing the terms on which the data is made available ("Public Domain")
|-
| '''Extents''' || A bounding box or polygon specified in WGS84, regardless of the original projection and datum of the data.
|-
| '''Projection''' || The original spatial projection of the data
|-
| '''Format''' || If the Source is a service this would be, for example OGC:WMS or OGC:WCS. For files, this is a text identifier which follows as a guideline the output of ''gdalinfo''.
|-
| '''URI''' || A URI giving the location of the data. If this is an OGC web service publishing geographic data, the URI would be that of a HTTP-based GetCapabilities request to it.
|-
| ''Scale'' ||
|-
| ''Resolution'' ||
|-
| ''Colour Depth'' ||
|-
| ''Transparency'' ||
|}

=== Relations ===

* A Data Set can be part of a Series of associated items
* A Data Set can have optionally many Layers
* A Data Set is made available by an Agent
* A Data Set is originally compiled by an Agent
* A Data Set may be a source of another Data Set

== Series ==

A Series is a collection of Data Sets. It provides a flexible container for a number of Data Sets which have common properties. Thus if all the Data Sets in a Series share a given property (e.g. they all have the same title, or the same date range or the same spatial extents), then that property can be attached to the Series and implicitly inherited by any Data Set belonging to the Series.

Thus a Series can be most usefully used to make an association between:

* A collection of data sets which are adjacent in space, yet represent one temporal snapshot (such as a collection of tiles comprising one larger image or model)
* A collection of data sets which are adjacent in time and may represent one spatial snapshot (such as a sequence of observations collected by an earth imaging satellite)
* A collection of data sets which are "the same" underlying data being made available in different formats, projections, or resolutions.

A Series can carry any of the properties that can be attached to a series.

== Agent ==

An Agent may be a person, an organisation, or a machine agent. This term derives from foaf:Agent, and is used in the same way as 'Principal' is used in security terms.

=== Properties ===

{|
|-
| '''Name''' || The name of the agent
|-
| '''Email''' || A contact email address given as mailto:foo@example.com
|-
| '''Description''' || More random details about the Agent
|-
| '''Location''' || A WGS84 lat-lon pair, or a URI indicating a near location
|}

=== Relations ===

* An Agent is the original provider of such-and-such a Data Set
* An Agent is the publisher of such-and-such a Data Set
* An Agent is the maintainer of such-and-such a Data Source

= Namespace / Ontology =

It is possible or advisable to extend many XML-based metadata carrier formats with ''namespaces'' which can provide semantics for different properties, taking a "mix-in" approach with the use of small vocabularies for different domains.

Thus DCLite4G attempts not to provide a full model for metadata for geographic information but to reuse properties from other well-known namespaces or ontologies - GeoRSS, Dublin Core, FOAF - and provide a subset of Dublin Core with extra rigour of expression suitable for better machine readability and reuse. This is also what is known as a ''Dublin Core Application Profile''.

http://xmlns.com/2008/dclite4g/ is the namespace reserved for DCLite4G. It should and will come to contain an OWL ontology showing the structure, providing where possible mappings to various metadata schemas.

= Examples =

Example serialisations of a DCLite4G minimal model in different common formats:

* [http://project.knowledgeforge.net/geometa/trac/browser/samples/iso19115?format=raw ISO19115]
* [http://project.knowledgeforge.net/geometa/trac/browser/samples/fgdc?format=raw FGDC]
* [http://project.knowledgeforge.net/geometa/trac/browser/samples/dublin-core?format=raw Dublin Core]
* [http://project.knowledgeforge.net/geometa/trac/browser/samples/rdf?format=raw RDF]

[http://project.knowledgeforge.net/geometa/trac/browser/dclite4g DCLite4G Python libraries] with genshi templates used to produce them.

= References =

* [http://www.fgdc.gov/standards/projects/FGDC-standards-projects/metadata/base-metadata/index_html FGDC geospatial metadata model]

* [http://dcs.dlese.org/preview/admin/view.do?id=TEST-000-000-000-008 GEON geospatial metadata model]

* [http://gcmd.nasa.gov/Aboutus/standards/fgdc_to_dif.html DIF geospatial metadata model]

* [http://georss.org/ GeoRSS]

* [http://portal.opengeospatial.org/files/?artifact_id=5929&version=2 OGC Catalog Services 2 Specification] '''6.3.3''', ''Core returnable properties''
* [http://portal.opengeospatial.org/files/?artifact_id=12604&version=1&format=pdf OGC ebRIM profile of CSW specification], '''Appendix B.5, Table B.3''' - ''Slots defined in the Basic package''
* [http://udig.refractions.net/docs/api-udig/net.refractions.udig.catalog/net/refractions/udig/catalog/IGeoResourceInfo.html iGeoResourceInfo class in uDig]
* [http://www.geodatacommons.umaine.edu/wpapers/CGD%20Metadata%20White%20Paper%20v2.pdf GeodataCommons Metadata Whitepaper]
* Open FOSSGIS Community [[Response to INSPIRE Metadata Draft]] Implementing Rules

= History =

* July 20th 2008
The first version of the DCLite4G model dates to late 2006/early 2007. In mid 2008 the vocabulary is significantly updated and somewhat simplified, after several iterations of a corresponding data registry and search service. The distinction between an abstract "Data Set" which has properties common to potentially many different "Data Sources" has been dropped. A "Series" is introduced, which takes most of the functions of "Data Set". Thus "Data Source" is now renamed "Data Set", resolving the semantic ambiguity in the model. Please see the history of this page

DCLite4G

2008-09-11T09:21:09Z

Wiki-JoWalsh:

DCLite4G is short for "Dublin Core Lightweight Profile for Geospatial". It is a ''minimal information model for metadata about geospatial data''. DCLite4G consists of:

* an abstract information model
* an implementation reference exploiting common standard vocabularies - [http://dublincore.org/ Dublin Core], [http://georss.org GeoRSS].
* a [http://dclite4g.xmlns.com/ namespace] used to define extra properties needed to usefully specify the properties of geospatial data.

The dclite4g namespace URL, [http://dclite4g.xmlns.com/schema contains an OWL ontology] showing the structure, providing where possible mappings to various metadata schemas.

= Information Model =

== Data Set ==

A Data Set is an abstract object. It corresponds to the ideal of a data set, independent of a physical form or an encoding in which it is being distributed. For example, "TIGER 2005" or "OpenStreetmap from 2007-04-20", or "SRTM" would be considered data sets.

A Data Set may be part of a Series comprising related items of geographic data.

An item of geographic information. Should have at least a title and a URI; ideally the URI is that of a resource where it is possible to access the information directly.

=== Properties ===
{|
|-
| '''Title''' || A name given to a data set. Does not have to be unique or "canonical".
|-
| '''Abstract''' || A text description of the contents of a data set, remarks on anything interesting contained therein.
|-
| '''Keywords''' || A layer may have none or many keywords associated with it.
|-
| '''Series''' || Indicates a Series to which a data set may belong. (see below)
|-
| '''Publisher''' || Contact information for the Agent publishing the data set
|-
| '''Originator''' || Contact information for the original creator of the data set
|-
| '''Publication Date''' || Date on which the data was made available
|-
| '''License''' || URL of a data license whose terms cover the distribution of this data set, OR a text string describing the terms on which the data is made available ("Public Domain")
|-
| '''Extents''' || A bounding box or polygon specified in WGS84, regardless of the original projection and datum of the data.
|-
| '''Projection''' || The original spatial projection of the data
|-
| '''Format''' || If the Source is a service this would be, for example OGC:WMS or OGC:WCS. For files, this is a text identifier which follows as a guideline the output of ''gdalinfo''.
|-
| '''URI''' || A URI giving the location of the data. If this is an OGC web service publishing geographic data, the URI would be that of a HTTP-based GetCapabilities request to it.
|-
| ''Scale'' ||
|-
| ''Resolution'' ||
|-
| ''Colour Depth'' ||
|-
| ''Transparency'' ||
|}

=== Relations ===

* A Data Set can be part of a Series of associated items
* A Data Set can have optionally many Layers
* A Data Set is made available by an Agent
* A Data Set is originally compiled by an Agent
* A Data Set may be a source of another Data Set

== Series ==

A Series is a collection of Data Sets. It provides a flexible container for a number of Data Sets which have common properties. Thus if all the Data Sets in a Series share a given property (e.g. they all have the same title, or the same date range or the same spatial extents), then that property can be attached to the Series and implicitly inherited by any Data Set belonging to the Series.

Thus a Series can be most usefully used to make an association between:

* A collection of data sets which are adjacent in space, yet represent one temporal snapshot (such as a collection of tiles comprising one larger image or model)
* A collection of data sets which are adjacent in time and may represent one spatial snapshot (such as a sequence of observations collected by an earth imaging satellite)
* A collection of data sets which are "the same" underlying data being made available in different formats, projections, or resolutions.

A Series can carry any of the properties that can be attached to a series.

== Agent ==

An Agent may be a person, an organisation, or a machine agent. This term derives from foaf:Agent, and is used in the same way as 'Principal' is used in security terms.

=== Properties ===

{|
|-
| '''Name''' || The name of the agent
|-
| '''Email''' || A contact email address given as mailto:foo@example.com
|-
| '''Description''' || More random details about the Agent
|-
| '''Location''' || A WGS84 lat-lon pair, or a URI indicating a near location
|}

=== Relations ===

* An Agent is the original provider of such-and-such a Data Set
* An Agent is the publisher of such-and-such a Data Set
* An Agent is the maintainer of such-and-such a Data Source

= Namespace / Ontology =

It is possible or advisable to extend many XML-based metadata carrier formats with ''namespaces'' which can provide semantics for different properties, taking a "mix-in" approach with the use of small vocabularies for different domains.

Thus DCLite4G attempts not to provide a full model for metadata for geographic information but to reuse properties from other well-known namespaces or ontologies - GeoRSS, Dublin Core, FOAF - and provide a subset of Dublin Core with extra rigour of expression suitable for better machine readability and reuse. This is also what is known as a ''Dublin Core Application Profile''.

http://xmlns.com/2008/dclite4g/ is the namespace reserved for DCLite4G. It should and will come to contain an OWL ontology showing the structure, providing where possible mappings to various metadata schemas.

= Examples =

Example serialisations of a DCLite4G minimal model in different common formats:

* [http://project.knowledgeforge.net/geometa/trac/browser/samples/iso19115?format=raw ISO19115]
* [http://project.knowledgeforge.net/geometa/trac/browser/samples/fgdc?format=raw FGDC]
* [http://project.knowledgeforge.net/geometa/trac/browser/samples/dublin-core?format=raw Dublin Core]
* [http://project.knowledgeforge.net/geometa/trac/browser/samples/rdf?format=raw RDF]

[http://project.knowledgeforge.net/geometa/trac/browser/dclite4g DCLite4G Python libraries] with genshi templates used to produce them.

= References =

* [http://www.fgdc.gov/standards/projects/FGDC-standards-projects/metadata/base-metadata/index_html FGDC geospatial metadata model]

* [http://dcs.dlese.org/preview/admin/view.do?id=TEST-000-000-000-008 GEON geospatial metadata model]

* [http://gcmd.nasa.gov/Aboutus/standards/fgdc_to_dif.html DIF geospatial metadata model]

* [http://georss.org/ GeoRSS]

* [http://portal.opengeospatial.org/files/?artifact_id=5929&version=2 OGC Catalog Services 2 Specification] '''6.3.3''', ''Core returnable properties''
* [http://portal.opengeospatial.org/files/?artifact_id=12604&version=1&format=pdf OGC ebRIM profile of CSW specification], '''Appendix B.5, Table B.3''' - ''Slots defined in the Basic package''
* [http://udig.refractions.net/docs/api-udig/net.refractions.udig.catalog/net/refractions/udig/catalog/IGeoResourceInfo.html iGeoResourceInfo class in uDig]
* [http://www.geodatacommons.umaine.edu/wpapers/CGD%20Metadata%20White%20Paper%20v2.pdf GeodataCommons Metadata Whitepaper]
* Open FOSSGIS Community [[Response to INSPIRE Metadata Draft]] Implementing Rules

= History =

* July 20th 2008
The first version of the DCLite4G model dates to late 2006/early 2007. In mid 2008 the vocabulary is significantly updated and somewhat simplified, after several iterations of a corresponding data registry and search service. The distinction between an abstract "Data Set" which has properties common to potentially many different "Data Sources" has been dropped. A "Series" is introduced, which takes most of the functions of "Data Set". Thus "Data Source" is now renamed "Data Set", resolving the semantic ambiguity in the model. Please see the history of this page