GetCapabilities Operation |
The GetCapabilites is a necessary operation.
The GetCapabilities operation allows WCS clients to retrieve service metadata from a WCS server and summary information about the data collections.
WCS clients may implement Get request using KVP encoding.
The main parameters of GetCapabilities operation request are shown in the following table:
Table 1 Parameters in GetCapabilities operation request
Request parameters | O/M | Description |
SERVICE=WCS |
Mandatory |
Service type. Request WCS service. Shall be "WCS". |
REQUEST=GetCapabilities |
Mandatory |
Request names. Name of the operation, shall be "GetCapabilities". |
AcceptVersions |
Optional |
The request version order of WCS server. Use a comma to separate different version and put the version that most want to return ahead. Returns the latest version in the service version if this parameter is default or is not the version that the server supports. |
Sections |
Optional |
Sections=Contents Requests the returned metadata Sections of server and uses a comma to separate the different sections. Returns all the information of current WCS server if this parameter is default or is not supported by the server. |
updateSequence |
Optional |
updateSequence=XXX The version number of metadata document. This is a increment and every change will add a value. Returns the latest version of the service metadata if this parameter is default or is not the version number that the server supports. |
AcceptFormats |
Optional |
AcceptFormats= text/xml The describe document format of request service. Use a comma to separate different format and put the format that most want to return ahead. Returns the 'text/xml' format if this parameter is default or is not the format that the server supports. |
Note: The case of the parameters is not important and the order of the request parameters can be random.
Request methods of the GetCapabilities operation are as follows:
<ServiceRoot>?SERVICE=WCS&REQUEST=GetCapabilities&AcceptVersions=1.1.2
ServiceRoot is the URI root directory of service and refer to the URI setting of service.
After started the iServer service, performs GetCapabilities request to data-world/wcs112 service as the following:
http://localhost:8090/iserver/services/data-world/wcs112?service=wcs&REQUEST=GetCapabilities
The returned response result see Response example.
The server returns the simple description that includes WCS service of the client request in the format of XML document.
The GetCapabilities operation returns the XML document that includes service metadata and summary information about the data collections. This document is composed of three parts:
Table 2 The returned contents of GetCapabilities operation
Element Name | Description |
ServiceIdentification |
Metadata about this specific server. |
ServiceProvider |
Service provider. The information description of the service provider. |
OperationsMetadata |
Metadata about the operation. Describes the operations the server provides. The three are required operations according to the WCS standard. |
Contents |
The table of contents. For the WCS, this section shall contain or reference brief descriptions of the coverages available from this server. |
Contents is used to describe brief descriptions of the coverages and mainly contains the following parts:
Table 3 The main contents of Contents section (all are optional)
Element Name | Description | Format |
coverageSummary |
Brief metadata describing a top-level coverage available from this WCS server. |
CoverageSummary data structure, see Table 4. |
supportedCRS |
Reference to CRS in which GetCoverage operation response may be expressed. |
URI |
supportedFormat |
Identifier of format in which GetCoverage operation response can be encoded. |
String |
otherSource |
Reference to another source of contents metadata |
|
The coverageSummary is composed of the following elements:
Table 4 The main content of the coverageSummary .
Element Name | O/M | Description | Whether it can be inherited |
(Description) |
Mandatory |
Description of a coverage. |
Optional |
metadata |
Optional |
More metadata about this coverage. |
Optional |
wgs84BoundingBox |
Optional |
Minimum bounding rectangle surrounding coverage, using WGS 84 CRS with decimal degrees and longitude before latitude |
Inherited when not provided. |
supportedCRS |
Optional |
CRS in which GetCoverage operation response may be expressed. |
Mandatory |
supportedFormat |
Optional |
Format in which GetCoverage operation response may be encoded. |
Mandatory |
Identifier |
Optional |
Unambiguous identifier of this coverage, unique for this WCS server |
Optional |
CoverageSummary |
Optional |
Brief metadata describing one subsidiary coverage available from this server |
Optional |
The server will return XML document as following if performs GetCapabilities request of the data-world/wcs112 service in the Request example.