2.6 Other Layer metadata
The OneGeology portal client will harvest the following information from each WMS layer.
Note, the indicative XPATH in the below tables relates to the GetCapabilities response document
|Metadata name||Indicative XPATH to metadata
(WMS version is shown in brackets)
|As already detailed above
|As already detailed above.
|You must provide a description of your layer data. You may wish to include other metadata, such as information about your organization and other data you make available. You may also wish to include a statement on access constraints.
(and short phrases)
|The Keyword "OneGeology" must be present to be able to search for services and layers with this keyword. OneGeologyEurope participants should also include relevant keywords chosen from the keyword list created for that project and listed in Appendix I below. The main purpose of these keywords is to make your services discoverable by a user searching in a catalogue of services and so well a clearly formed but limited in length list of geosciences domain specific is ideal and all OneGeology global participants may want to consider using items from this proposed Onegeology-Europe list also. It has been formed by looking at many such lists available around the world including the European GEMET thesaurus found at:
The following broad concepts are good starting points
http://eionet.europa.eu/gemet/concept?cp=2405 (earth science)
http://eionet.europa.eu/gemet/concept?cp=3648 (geological process)
Each keyword (or short phrase) must be contained within its own <keyword> element.
In addition to this we also require you to add a number of special ‘Cataloguing keywords‘ to help the portal and catalogue services better index your layers. These special keywords have a term then an ‘@’ symbol and then your value for the term, as below:
*Continent: continent@value Required *Subcontinent: subcontinent@value Conditional *Geographic area (usually country): geographicarea@value Required *State(Region or province): subarea@value Conditional *Data provider: dataprovider@value Required *Service provider: serviceprovider@value Required
The geographicarea@value represents a verbalization of the code that starts a layer name. For most layers geographicarea@value will be the country; this INCLUDES layers that only show a sub-region or state within a country.
The values for Continent, Subcontinent and Country must be taken from the United Nations (UN) list http://unstats.un.org/unsd/methods/m49/m49regin.htm used by the portal.
Conditional keywords are required if they apply. Eg. If the geographic area is a state or province then the subarea keyword is required.
In addition we would like that you also supply the following two special ‘Metadata keywords‘ for each layer. These keywords help make the GetCapabilities response ISO19115 core compliant.
*Layer (Data set) date: DS_DATE@value *Layer (Data set) topic category: DS_TOPIC@value (one or more as appropriate)
The topic category is taken from the ISO 19119 topic category listing. A good reference to the categories and what they represent is found at: http://gcmd.nasa.gov/User/difguide/iso_topics.html. We anticipate that most layers would have a DS_TOPIC@geoscientificinformation keyword.
So for example, the layer “AFG AGS 1:1M Bedrock Age” would include the following keywords:
Note, that we have the country twice, once as one of the OneGeology portal special keywords, and once as the country only; this is because we recognize that the service may be consumed (and catalogued) by services other than OneGeology. We don’t include a subarea@ keyword in this list because that would not be appropriate in this instance.
In WMS version 1.1.1 a comma separated list of (latitude-longitude decimal degree) coordinates defining an imaginary box that entirely encompasses the map data. It is always specified as minimum-X, minimum-Y, maximum-X, and maximum-Y.
In WMS version 1.3.0 four elements each describing a single bounding limit (always in the order: west, east, south, north)
Spatial (1.1.1) or
A list of one or more horizontal ‘ Spatial Reference Systems’ that the layer can handle (will accept requests in and return results based upon those SRS). In WMS 1.1.1, the returned image is always projected using a pseudo-Plate Carrée projection that plots Longitude along the X-axis and Latitude along the Y-axis.
For example, the exemplar service lists the following Spatial Reference Systems:
The BoundingBox attributes indicate the edges of the bounding box in units of the specified spatial reference system, for example the exemplar service provides the following BoundingBox information for the GBR BGS 1:625k Bedrock Lithology layer:
Example WMS 1.1.1 response
<BoundingBox SRS=“EPSG:4326” minx=“-8.64846” miny=“49.8638” maxx=“1.76767” maxy=“60.8612” />
Example WMS 1.3.0 response
<BoundingBox CRS=“EPSG:4326” minx=“49.8638” miny=“-8.64846” maxx=“60.8612” maxy=“1.76767” />
Please note the swap in x,y axes order for the geographic coordinate systems EPSG:4258 and EPSG:4326 between WMS versions. In WMS version 1.3.0 the x-axis is the first axis in the CRS definition, and the y-axis is the second. EPSG geographic coordinate reference systems follow ISO 6709 and ALWAYS list latitude before longitude.
|DataURL (optional)||/WMT_MS_Capabilities/Capability/Layer/Layer/DataURL (1.1.1)
|This may be used to provide further information about all the digital data offered by the data provider, though it is primarily used to provide a link to non-standards compliant metadata for the layer in question.
| You should supply one or more on-line resources offering detailed, standardized (either as "FGDC:1998" or "ISO 19115:2003") metadata about the layer data. If your metadata is not available in either of these standards you MUST instead use a DataURL.
The core ISO 19115:2003 metadata required to be compliant is shown in section 2.7. Note, there are no formatting requirements; this information could be provided as xml or html or text or pdf etc as long as it accessible on the web.
Example WMS 1.1.1 response
Example WMS 1.3.0 response
<MetadataURL type=“ISO 19115:2003”>
Please note: the defined attribute value to indicate ISO 19115:2003 metadata is “ISO 19115:2003” in WMS version 1.3.0 as opposed to “TC211” in version 1.1.1. In version 1.3.0, communities may also define their own attributes.
|Minimum Scale||/WMT_MS_Capabilities/Capability/Layer/Layer/ScaleHint@min (1.1.1)
|A hint to the minimum scale at which the map will not be zoomed in beyond. This is cited in units relating to the diagonal dimension of the screen in units relevant to the software providing the service, and would normally be populated automatically by the software.|
|Maximum Scale||/WMT_MS_Capabilities/Capability/Layer/Layer/ScaleHint@max (1.1.1)
|A hint to the maximum scale at which the map will not be zoomed out beyond. This is cited in units relating to the diagonal dimension of the screen in units relevant to the software providing the service, and would normally be populated automatically by the software.|
|Data owner||/WMT_MS_Capabilities/Capability/Layer/Layer/Attribution/Title (1.1.1)
Descriptive text for the Data owner organization (not service provider), such as British Geological Survey (BGS). E.g. Something like:
We no longer request that you provide this Data owner organization information in the Layer Attribution section, as we now require you to provide this information as part of @ style keywords (see above).
|Is the layer queryable||/WMT_MS_Capabilities/Capability/Layer/Layer@queryable (1.1.1)
|Parameter to indicate whether a GetFeatureInfo request is allowed on the layer
|Legend url||/WMT_MS_Capabilities/Capability/Layer/Layer/Style/LegendURL (1.1.1)
|We require you to have some sort of legend to accompany your map data. If you are using the latest version of MapServer server, this will be created for you automatically using the inbuilt SLD capability. If your WMS server is not SLD capable, or if you have a complex legend, you may add the LegendURL manually in your GetCapabilities response document. See below section style examples.
|Style name||/WMT_MS_Capabilities/Capability/Layer/Layer/Style/Name (1.1.1)
|Computer readable name for the style. If you have only one style this would normally be given the name 'default'. See below style examples.|
|Style title||/WMT_MS_Capabilities/Capability/Layer/Layer/Style/Title (1.1.1)
|Human readable title for the style. See below style examples.|
Section last modified : 29 February 2012.