DCLite4G - Revision history

Wiki-JoWalsh: /* Properties */

2008-09-11T11:34:00Z

Properties

Wiki-JoWalsh: /* Series */

2008-09-11T11:32:59Z

Series

Wiki-JoWalsh at 11:01, 11 September 2008

2008-09-11T11:01:04Z

Wiki-JoWalsh: /* Namespace / Ontology */

2008-09-11T11:00:41Z

Namespace / Ontology

Wiki-JoWalsh at 09:21, 11 September 2008

2008-09-11T09:21:58Z

Wiki-JoWalsh at 09:21, 11 September 2008

2008-09-11T09:21:09Z

Wiki-JoWalsh at 12:32, 21 July 2008

2008-07-21T12:32:49Z

Wiki-JoWalsh: removed Layer description as it is subsumed by DataSet now

2008-07-21T12:31:32Z

removed Layer description as it is subsumed by DataSet now

Wiki-JoWalsh: noted changes to model, not sure what status of Layer is currently

2008-07-20T08:43:32Z

noted changes to model, not sure what status of Layer is currently

Wiki-JoWalsh: /* Properties */

2008-02-28T17:23:56Z

Properties

@@ Line 27: / Line 27: @@
 | '''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)
 |-

@@ Line 72: / Line 72: @@
 * 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.
+A Series can carry any of the properties that can be attached to a data set.
 == Agent ==

← Older revision		Revision as of 11:01, 11 September 2008
Line 5:		Line 5:
	* a [http://dclite4g.xmlns.com/ namespace] used to define extra properties needed to usefully specify the properties of geospatial data.		* 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.	+	The dclite4g namespace URL, [http://dclite4g.xmlns.com/schema.rdf http://dclite4g.xmlns.com/schema.rdf] contains an OWL ontology showing the structure, providing where possible mappings to various metadata schemas.

@@ Line 104: / Line 104: @@
 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.
+http://dclite4g.xmlns.com/schema.rdf is the namespace reserved for DCLite4G. It contains an OWL ontology showing the structure, providing where possible mappings to various metadata schemas.
 = Examples =

← Older revision		Revision as of 09:21, 11 September 2008
Line 5:		Line 5:
	* a [http://dclite4g.xmlns.com/ namespace] used to define extra properties needed to usefully specify the properties of geospatial data.		* 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.	+	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.

@@ Line 3: / Line 3: @@
 * an abstract information model
 * an implementation reference exploiting common standard vocabularies - [http://dublincore.org/ Dublin Core], [http://georss.org GeoRSS].
-* a namespace used to define extra properties needed to usefully specify the properties of geospatial data.
+* a [http://dclite4g.xmlns.com/ namespace] used to define extra properties needed to usefully specify the properties of geospatial data.
-The URL at which the namespace lives, contains an OWL ontology showing the structure, providing where possible mappings to various metadata schemas.
+The dclite4g namespace URL, [http://dclite4g.xmlns.com/schema contains an OWL ontology] showing the structure, providing where possible mappings to various metadata schemas.

@@ Line 14: / Line 14: @@
 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 can be associated with one or many Data Sources which correspond to concrete resources which can be got at in order to explore the data. All the properties which are shared across multiple Data Sources, are properties of the Data Set. If the properties of a Source are different - e.g. a smaller spatial extent, or a generalised subset of features in the same extent - then it is an instance of a different Data Set.
+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.

← Older revision		Revision as of 12:31, 21 July 2008
Line 77:		Line 77:

	A Series can carry any of the properties that can be attached to a series.		A Series can carry any of the properties that can be attached to a series.
−
−	~~== Layer ==~~
−
−	Vector data formats often provide multiple Layers of data as part of a data set. OGC Web Services also often provide multiple Layers through one service. This is useful metadata which it would be a shame to throw away.
−
−	~~=== Properties ===~~
−
−	{\|
−	\|-
−	~~\| '''Name''' \|\| The layer's name, free text~~
−	\|-
−	~~\| '''Abstract''' \|\| A description of the contents of the layer, with any remarks of interest~~
−	\|-
−	~~\| '''Keywords''' \|\| A layer may have none or many keywords associated with it.~~
−	\|}
−
−	~~=== Relations ===~~
−
−	* A Data Set can have none or many Layers
−	~~(note - though we get information about layers through looking at a Data Source, they are related to the abstract Data Set, because the Layers on all the different Sources will be the same.~~

	== Agent ==		== Agent ==

@@ Line 17: / Line 17: @@
 One goal in this is to make it more possible to trace and annotate the recombination of different sources of data into one package - keeping track of what is known as "lineage" of data packages.
 === Properties ===
 {|
 |-
-| '''Name''' || A name given to a data set. Does not have to be unique or "canonical".
+| '''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.
 |-
 | '''Publisher''' || Contact information for the Agent publishing the data set
@@ Line 33: / Line 39: @@
 | '''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.
+| '''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
 |-
-| ''Scale'' || (for Raster, Coverage types)
+| '''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''.
 |-
-| ''Resolution'' || (for Raster, Coverage types)
+| ''Resolution'' ||
 |-
-| ''Colour Depth'' || (for Raster, Coverage types) e.g. 8, 16, 24 bit
+| ''Colour Depth'' ||
 |-
-| ''Transparency'' || (for Raster type)
+| ''Transparency'' ||
 |}
 === Relations ===
 * 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
-== Data Source ==
+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:
-=== Relations ===
+* 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 Data Source is an instance of exactly one Data Set
+A Series can carry any of the properties that can be attached to a series.
 == Layer ==
@@ Line 129: / Line 128: @@
 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/2007/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.
+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 =
@@ Line 157: / Line 156: @@
 * [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