Weather Observation Definition Format DTD
From:  http://zowie.metnet.navy.mil/~spawar/JMV-TNG/XML/OMF.dtd
Date:  1998-09-14

<!-- <!DOCTYPE OMF SYSTEM "OMF.dtd" [ -->
<!--  Weather Observation Definition Format DTD -->
<!--  This is the OMF XML DTD.  It can be referred to using the
formal public identifier 
        -//METNET//OMF 1.0//EN
      For description, see OMF.html

      $Id: OMF.dtd,v 3.1 1998/08/24 21:59:50 oleg Exp oleg $
--> 

<!--  Weather Observation Definition Format      -->

<!--  Basic attributes     -->

<!ENTITY % TStamp-type "NMTOKEN">
<!ENTITY % TRange-type "CDATA">
<!ENTITY % TStamp "TStamp %TStamp-type; #REQUIRED">
<!ENTITY % TRange "TRange %TRange-type; #REQUIRED">
<!ENTITY % LatLon "LatLon CDATA #REQUIRED">
<!ENTITY % LatLons "LatLons CDATA #REQUIRED">
<!ENTITY % BBox-REQD "BBox CDATA #REQUIRED">
<!ENTITY % BBox-OPT "BBox CDATA #IMPLIED">
<!ENTITY % BId "BId NMTOKEN #REQUIRED">
<!ENTITY % SName "SName CDATA #REQUIRED">
<!ENTITY % Elev "Elev NMTOKEN #IMPLIED">

<!--  Basic elements     -->

<!ELEMENT VALID (#PCDATA)>
<!ATTLIST VALID %TRange;>

<!--  A collection of weather observation reports     -->

<!ELEMENT Reports ( METAR | SPECI )*>
<!ATTLIST Reports %TStamp;>

<!--  Common report attributes     -->
<!ENTITY % ReportAttrs 
    "%TStamp; %LatLon; %BId; %SName; %Elev;
     Vis NMTOKEN  #IMPLIED
     Ceiling NMTOKEN  #IMPLIED
    ">

<!--  METAR and SPECI reports     -->

<!ELEMENT METAR (#PCDATA)>
<!ATTLIST METAR %ReportAttrs;>

<!ELEMENT SPECI (#PCDATA)>
<!ATTLIST SPECI %ReportAttrs;>

<!--  A collection of weather hazard advisories     -->

<!ELEMENT Advisories ( SIGMET | AIRMET | WW )* >
<!ATTLIST Advisories %TStamp;>

<!--  A SIGMET advisory   -->

<!ELEMENT SIGMET (VALID, AFFECTING?, EXTENT, BODY) >
<!ATTLIST SIGMET
        class (CONVECTIVE| HOTEL| INDIA| UNIFORM| VICTOR| WHISKEY) #REQUIRED
        id NMTOKEN #REQUIRED
        %TStamp;
        %BBox-OPT;
>

<!ELEMENT AFFECTING (#PCDATA)>

<!ELEMENT EXTENT (#PCDATA)>
<!ATTLIST EXTENT
	Shape (AREA| LINE| POINT) #REQUIRED
	%LatLons;
>

<!ELEMENT BODY (#PCDATA)>


<!--  A collection of weather forecasts     -->

<!ELEMENT Forecasts ( TAF )* >
<!ATTLIST Forecasts %TStamp;>

<!--  A Terminal Aerodrome Forecast   -->

<!ELEMENT TAF ( VALID, PERIOD+ ) >
<!ATTLIST TAF
	%TStamp; %LatLon; %BId; %SName;
>

<!ELEMENT PERIOD ( PREVAILING, VAR* )>
<!ATTLIST PERIOD
	%TRange;
	Title NMTOKEN #IMPLIED
>

<!ELEMENT PREVAILING (#PCDATA)>

<!ELEMENT VAR (#PCDATA)>
<!ATTLIST VAR
	%TRange;
	Title CDATA #REQUIRED
>


<!-- ]> -->