| Name | Type | Use | Default | Fixed | annotation |
| id | ID | optional | | | |
| updatable | boolean | optional | | | | documentation | | Specifies if the value of a data component can be updated externally (i.e. is variable) |
|
| optional | boolean | optional | false | | | documentation | | Specifies that data for this component can be omitted in the datastream |
|
| definition | anyURI | optional | | | | documentation | | Reference to semantic information defining the precise nature of the component |
|
| referenceFrame | anyURI | optional | | | | documentation | | Frame of reference (usually temporal or spatial) with respect to which the value of the component is expressed. A reference frame anchors a value to a real world datum. |
|
| axisID | string | optional | | | | documentation | | Specifies the reference axis (refer to gml:axisID). The reference frame URI should also be specified unless it is inherited from parent Vector |
|
| referenceTime | dateTime | optional | | | | documentation | | Specifies the origin of the temporal reference frame as an ISO8601 date (used to specify time after an epoch that is to say in a custom frame) |
|
| localFrame | anyURI | optional | | | | documentation | | Temporal frame of reference whose origin is located by the value of this component |
|