SIGMET OBS AT nnnnZ ENTIRE FIR

In a volcanic ash SIGMET, the schema comments say that ENTIRE FIR should be represented such that "the geometry should be an xlink to the sampled feature for this SIGMET". However, doesn't allow an xref:hlink attribute. In the forecast I can see a possibility:

... This validates but is it correct? However, in the I don't see how to do anything similar because the also wraps the Level elements which still need to be included. How can we encode OBS AT 1210Z ENTIRE FIR? An example TAC from EUR Doc 014: > YUDD SIGMET 2 VALID 101200/101600 YUSO – YUDD SHANLON FIR/UIR VA CLD FCST AT 1200Z ENTIRE FIR FL250/370 STNR WKN= I'm posting here because I didn't get any replies on the group: https://groups.google.com/a/wmo.int/d/msg/cbs-tt-avxml/udbYFyTiza4/2_7W2mEfCAAJ

I have to say that iwxxm:geometry in SIGMET was designed to have xlink:href but due to some mistakes it was incorrectly defined in the schema as:

<element name="geometry" type="aixm:AirspaceVolumePropertyType">

which should instead be:

<element name="geometry" type="iwxxm:AirspaceVolumePropertyType">

We fixed this in IWXXM 3.0.0. In this version, the FIR/UIR/CTA is defined to be:

    <iwxxm:issuingAirTrafficServicesRegion>
        <aixm:Airspace gml:id="uuid.eb9d349c-242c-4193-981a-935ee2e547a2">
            <aixm:timeSlice>
                <aixm:AirspaceTimeSlice gml:id="uuid.23909d58-4be9-43a1-8eb8-2d1e3b64432e">
                    <gml:validTime/>
                    <aixm:interpretation>SNAPSHOT</aixm:interpretation>
                    <aixm:type>OTHER:FIR_UIR</aixm:type>
                    <aixm:designator>YUDD</aixm:designator>
                    <aixm:name>SHANLON FIR/UIR</aixm:name>
                    <!-- FIR boundary can be reported in an aixm:geometryComponent -->
                </aixm:AirspaceTimeSlice>
            </aixm:timeSlice>
        </aixm:Airspace>
    </iwxxm:issuingAirTrafficServicesRegion>

where the FIR/UIR/CTA boundary is defined as:

                    <aixm:geometryComponent>
                        <aixm:AirspaceGeometryComponent gml:id="...">
                            <aixm:theAirspaceVolume>
                                <aixm:AirspaceVolume gml:id="uuid.eb9d349c-242c-4193-981a-935ee2e547a2">
                                    ...
                                </aixm:AirspaceVolume>
                            </aixm:theAirspaceVolume>
                        </aixm:AirspaceGeometryComponent>
                    </aixm:geometryComponent>

You can then make reference by:

    `<iwxxm:geometry xlink:href="#uuid.eb9d349c-242c-4193-981a-935ee2e547a2"/>`

wmo-im / iwxxm

SIGMET OBS AT nnnnZ ENTIRE FIR #129