The gml:RectifiedGridCoverage is a discrete point coverage based on a rectified grid. It is similar to the grid coverage except that the points of the grid are geometrically referenced. The rectified grid coverage has a domain that is a gml:RectifiedGrid geometry.
The attribute gml:id supports provision of a handle for the XML element representing a GML Object. Its use is mandatory for all GML objects. It is of XML type ID, so is constrained to be unique in the XML document within which it occurs.
Source
<element name="RectifiedGridCoverage" type="gml:DiscreteCoverageType" substitutionGroup="gml:AbstractDiscreteCoverage"><annotation><documentation>The gml:RectifiedGridCoverage is a discrete point coverage based on a rectified grid. It is similar to the grid coverage except that the points of the grid are geometrically referenced. The rectified grid coverage has a domain that is a gml:RectifiedGrid geometry.</documentation></annotation></element>