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ARLAS-OGC-API

ARLAS Exploration offers an OGC API that makes the ARLAS catalog interoperable with GIS applications. The catalog is explorable through two standard endpoints:

  • A WFS endpoint for each collection reference that provides access to the geographic features of the collection.
  • A CSW endpoint to discover the available collections.

A third endpoint is available to get an Opensearch description of CSW service.

URL Schema

The table below lists the URL endpoints and their ogc "parameters". The parameters are separated with the character &.

PATH Template Description
/arlas/ogc/wfs/{collection}?wfsParameters Download the features of the given {collection}
/arlas/ogc/csw/?cswParameters Discover the available collections in ARLAS
/arlas/ogc/csw/opensearch OpenSearch CSW Description Document

URL Parameters

WFS Parameters

The following parameters are mandatory and must be specified for all WFS requests

Parameter Description Possible values
service name of the service WFS
version Supported WFS standard version 2.0.0
request The WFS operation to perform Six possible values. Check the table below

The table below sums up the WFS operations supported by ARLAS-server

Operation Description
GetCapabilities Generates a metadata document describing the WFS service provided by ARLAS-server as well as valid WFS operations and parameters
DescribeFeatureType Returns a description of feature types supported by WFS service
GetFeature Returns a selection of features from the given {collection} including geometry and attribute values
GetPropertyValue Fetches the value of a given feature property of the {collection}
ListStoredQueries Returns the list of the stored queries of WFS server
DescribeStoredQueries Returns a metadata document describing the stored queries of WFS server

According to the chosen operation, you can specify a set of parameters

request=GetCapabilities

You can specify a language parameter :

Parameter Description Possible values Mandatory/Optional
language Language of the metadata One of the official languages of the European Community expressed in conformity with ISO 639-2 Optional

This parameter conforms to INSPIRE recommendations.

  • If the requested language is contained in the list of supported languages, then natural language metadata elements are returned in the requested language.
  • If the requested language is not supported by the WFS, then this parameter is ignored.

request=DescribeFeatureType

This operation gives information about the feature type before requesting the actual data.

Parameter Description Possible values Mandatory/Optional
typenames Name of the feature type to describe Must contain the name of the {collection} Optional

request=GetFeature

This operation returns a selection of features from the given {collection}.

You can specify pagination parameters :

Parameter Description Possible values Mandatory/Optional
count Maximum number of returned features Integer Optional
startindex Index to start the search from Integer Optional

You can use stored queries :

Parameter Description Possible values Mandatory/Optional
storedquery_id Id of a storied query in WFS server. urn:ogc:def:query:OGC-WFS::GetFeatureById Optional
id Id of a feature to query. text Mandatory if storedquery_id is specified

You can query data using the following parameters

Parameter Description Possible values Mandatory/Optional
resourceid Id of a feature to query. text Optional
bbox A geographic extend used to query any feature having its centroid contained within it. west, south, east, north Optional
filter A filter used to select features by evaluating an expression Filter Encoding language 2.0.2 Reference Optional
srsname crs of the features http://www.opengis.net/def/crs/epsg/0/4326, urn:ogc:def:crs:EPSG::4326 Optional
typenames Name of the feature type to describe Must contain the name of the {collection} Optional

request=GetPropertyValue

This operation returns the value of a feature property.

You must specify the feature property :

Parameter Description Possible values Mandatory/Optional
valueReference Feature type property text Mandatory

You can specify pagination parameters :

Parameter Description Possible values Mandatory/Optional
count Maximum number of returned features Integer Optional
startindex Index to start the search from Integer Optional

You can use stored queries :

Parameter Description Possible values Mandatory/Optional
storedquery_id Id of a storied query in WFS server. urn:ogc:def:query:OGC-WFS::GetFeatureById Optional
id Id of a feature to query. text Mandatory if storedquery_id is specified

You can query data using the following parameters

Parameter Description Possible values Mandatory/Optional
resourceid Id of a feature to query. text Optional
bbox A geographic extend used to query any feature having its centroid contained within it. west, south, east, north Optional
filter A filter used to select features by evaluating an expression Filter Encoding language 2.0.2 Reference Optional
typenames Name of the feature type to describe Must contain the name of the {collection} Optional

Note

  • bbox and resourceid can't be used together
  • bbox and filter can't be used together
  • resourceid and filter can't be used together

CSW Parameters

The following parameters are mandatory and must be specified for all CSW requests

Parameter Description Possible values
service name of the service CSW
version Supported CSW standard version 3.0.0
request The CSW operation to perform Three possible values. Check the table below

The table below sums up the CSW operations supported by ARLAS-server

Operation Description
GetCapabilities Generates a metadata document describing the CSW service provided by ARLAS-server as well as valid CSW operations and parameters
GetRecords Returns collection references metadata and identifier
GetRecordById Returns a specific collection reference metadata and identifier

According to the chosen operation, you can specify a set of parameters

request=GetCapabilities

You can specify a language parameter :

Parameter Description Possible values Mandatory/Optional
language (1) Language of the metadata One of the official languages of the European Community expressed in conformity with ISO 639-2 Optional
sections Specifies which parts of the GetCapabilities response to include ServiceIdentification, ServiceProvider, OperationsMetadata, Filter_Capabilities, All Optional

(1) This parameter conforms to INSPIRE recommendations.

  • If the requested language is contained in the list of supported languages, then natural language metadata elements are returned in the requested language.
  • If the requested language is not supported by the WFS, then this parameter is ignored.

request=GetRecords & request=GetRecordById

The following parameters are common to GetRecords and GetRecordById

You can specify pagination parameters :

Parameter Description Possible values Mandatory/Optional
maxRecords Maximum number of returned collections Integer Optional
startposition Index to start the search from Integer Optional

You can choose which metadata to return :

Parameter Description Possible values Mandatory/Optional
elementName Metadata elements to return (1). Comma separated metadata elements. For instance : title,subject. Optional
elementSetName Group of metada elements to return. brief, summary (default) or full Optional
typenames Defines the level of details present in the result set. Record, csw:Record or gmd:MD_Metadata Optional

(1) Possible values of elementName are : title, abstract, identifier, subject, creator, publisher, contributor, type, format, source, language, modified, boundingbox.

Note

  • elementName and elementSetName can't be used together

You can choose the format :

Parameter Description Possible values Mandatory/Optional
outputFormat Whether to return response in application/xml or application/atom+xml format application/xml (default), application/atom%2Bxml Optional
outputSchema The schema of output of GetRecords/GetRecordById response http://www.opengis.net/cat/csw/3.0.0 (default) or http://www.isotc211.org/2005/gmd Optional

You can query collection references metadata using the following parameters

Parameter Description Possible values Mandatory/Optional
recordIds Comma separated ids of collections text Optional
id id of a collection text Mandatory for GetRecordById
q Full text search on collection references text Optional
bbox A geographic extend used to query any collection that intersects it. west, south, east, north Optional
constraint A filter used to select collections references by evaluating an expression Filter Encoding language 2.0.2 Reference Optional
constraintLanguage Language of the constraint Filter Optional

Note

  • bbox and recordids can't be used together
  • recordids and q can't be used together