Web Map Service Implementation Specification

This annex contains the WMS Capabilities Document Type Definition corresponding to this version of the specification. The DTD may also be found on-line at http://www.digitalearth.gov/wmt/xml/capabilities_1_1_1.dtd. Comments in the DTD are informative; in case of conflict with the main body of this specification the main body takes precedence.

<!ELEMENT WMT_MS_Capabilities (Service, Capability) >

<!ATTLIST WMT_MS_Capabilities
	  version CDATA #FIXED "1.1.1"
	  updateSequence CDATA #IMPLIED>

<!-- Elements used in multiple places. -->

<!-- The Name is typically for machine-to-machine communication. -->
<!ELEMENT Name (#PCDATA) >

<!-- The Title is for informative display to a human. -->
<!ELEMENT Title (#PCDATA) >

<!-- The abstract is a longer narrative description of an object. -->
<!ELEMENT Abstract (#PCDATA) > 

<!-- An OnlineResource is typically an HTTP URL.  The URL is placed in the
xlink:href attribute.  The xmlns:xlink attribute is a required XML namespace
declaration. -->
<!ELEMENT OnlineResource EMPTY>
<!ATTLIST OnlineResource
          xmlns:xlink CDATA #FIXED "http://www.w3.org/1999/xlink"
          xlink:type CDATA #FIXED "simple"
          xlink:href CDATA #REQUIRED >

<!-- A container for listing an available format's MIME type. -->
<!ELEMENT Format (#PCDATA) >


<!-- General service metadata. -->

<!ELEMENT Service (Name, Title, Abstract?, KeywordList?, OnlineResource,
                   ContactInformation?, Fees?, AccessConstraints?) >

<!-- List of keywords or keyword phrases to help catalog searching. -->
<!ELEMENT KeywordList (Keyword*) >

<!-- A single keyword or phrase. -->
<!ELEMENT Keyword (#PCDATA) >

<!-- Information about a contact person for the service. -->
<!ELEMENT ContactInformation  (ContactPersonPrimary?, ContactPosition?,
                               ContactAddress?, ContactVoiceTelephone?,
                               ContactFacsimileTelephone?,
                               ContactElectronicMailAddress?) >

<!--The primary contact person.-->
<!ELEMENT ContactPersonPrimary  (ContactPerson, ContactOrganization) >

<!--The person to contact.-->
<!ELEMENT ContactPerson  (#PCDATA) >

<!--The organization supplying the service.-->
<!ELEMENT ContactOrganization  (#PCDATA) >

<!--The position title for the contact person.-->
<!ELEMENT ContactPosition  (#PCDATA) >

<!--The address for the contact supplying the service.-->
<!ELEMENT ContactAddress  (AddressType,Address,City,StateOrProvince,PostCode,
               Country) >

<!--The type of address.-->
<!ELEMENT AddressType  (#PCDATA) >

<!--The street address.-->
<!ELEMENT Address  (#PCDATA) >

<!--The address city.-->
<!ELEMENT City  (#PCDATA) >

<!--The state or province.-->
<!ELEMENT StateOrProvince  (#PCDATA) >

<!--The zip or postal code.-->
<!ELEMENT PostCode  (#PCDATA) >

<!--The address country.-->
<!ELEMENT Country  (#PCDATA) >

<!--Contact telephone number.-->
<!ELEMENT ContactVoiceTelephone  (#PCDATA) >

<!--The contact fax number.-->
<!ELEMENT ContactFacsimileTelephone  (#PCDATA) >

<!--The e-mail address for the contact.-->
<!ELEMENT ContactElectronicMailAddress  (#PCDATA) >


<!-- Elements indicating what fees or access constraints are imposed. -->
<!ELEMENT Fees (#PCDATA)>
<!ELEMENT AccessConstraints (#PCDATA)>


<!-- A Capability lists available request types, how exceptions
may be reported, and whether any vendor-specific capabilities are defined.  It
also includes an optional list of map layers available from this server. -->
<!ELEMENT Capability 
          (Request, Exception, VendorSpecificCapabilities?,
	   UserDefinedSymbolization?, Layer?) >

<!-- Available WMS Operations are listed in a Request element. -->
<!ELEMENT Request (GetCapabilities, GetMap, GetFeatureInfo?,
                   DescribeLayer?, GetLegendGraphic?, GetStyles?, PutStyles?) >

<!-- For each operation offered by the server, list the available output
formats and the online resource. -->
<!ELEMENT GetCapabilities (Format+, DCPType+)>
<!ELEMENT GetMap (Format+, DCPType+)>
<!ELEMENT GetFeatureInfo (Format+, DCPType+)>
<!-- The following optional operations only apply to SLD-enabled WMS -->
<!ELEMENT DescribeLayer (Format+, DCPType+)>
<!ELEMENT GetLegendGraphic (Format+, DCPType+)>
<!ELEMENT GetStyles (Format+, DCPType+)>
<!ELEMENT PutStyles (Format+, DCPType+)>

<!-- Available Distributed Computing Platforms (DCPs) are
listed here.  At present, only HTTP is defined. -->
<!ELEMENT DCPType (HTTP) >

<!-- Available HTTP request methods.  One or both may be supported. -->
<!ELEMENT HTTP (Get | Post)+ >

<!-- URL prefix for each HTTP request method. -->
<!ELEMENT Get (OnlineResource) >
<!ELEMENT Post (OnlineResource) >

<!-- An Exception element indicates which error-reporting formats are supported. -->
<!ELEMENT Exception (Format+)>

<!-- Optional user-defined symbolization (used only by SLD-enabled WMSes). -->
<!ELEMENT UserDefinedSymbolization EMPTY >
<!ATTLIST UserDefinedSymbolization
          SupportSLD (0 | 1) "0"
          UserLayer (0 | 1) "0"
          UserStyle (0 | 1) "0"
          RemoteWFS (0 | 1) "0" >

<!-- Nested list of zero or more map Layers offered by this server. -->
<!ELEMENT Layer ( Name?, Title, Abstract?, KeywordList?, SRS*,
                  LatLonBoundingBox?, BoundingBox*, Dimension*, Extent*,
                  Attribution?, AuthorityURL*, Identifier*, MetadataURL*, DataURL*,
                  FeatureListURL*, Style*, ScaleHint?, Layer* ) >

<!-- Optional attributes-->
<!ATTLIST Layer queryable (0 | 1) "0"
                cascaded CDATA #IMPLIED
                opaque (0 | 1) "0"
                noSubsets (0 | 1) "0"
                fixedWidth CDATA #IMPLIED
                fixedHeight CDATA #IMPLIED >
          
<!-- Identifier for a single Spatial Reference Systems (SRS). -->
<!ELEMENT SRS (#PCDATA) >

<!-- The LatLonBoundingBox attributes indicate the edges of the enclosing
rectangle in latitude/longitude decimal degrees (as in SRS EPSG:4326 [WGS1984
lat/lon]). -->
<!ELEMENT LatLonBoundingBox EMPTY>
<!ATTLIST LatLonBoundingBox 
          minx CDATA #REQUIRED
          miny CDATA #REQUIRED
          maxx CDATA #REQUIRED
          maxy CDATA #REQUIRED>

<!-- The BoundingBox attributes indicate the edges of the bounding box
in units of the specified spatial reference system. -->
<!ELEMENT BoundingBox EMPTY>
<!ATTLIST BoundingBox 
          SRS CDATA #REQUIRED
          minx CDATA #REQUIRED
          miny CDATA #REQUIRED
          maxx CDATA #REQUIRED
          maxy CDATA #REQUIRED
          resx CDATA #IMPLIED
          resy CDATA #IMPLIED>

<!-- The Dimension element declares the _existence_ of a dimension. -->
<!ELEMENT Dimension EMPTY >
<!ATTLIST Dimension
          name CDATA #REQUIRED
          units CDATA #REQUIRED
          unitSymbol CDATA #IMPLIED>

<!-- The Extent element indicates what _values_ along a dimension are valid. -->
<!ELEMENT Extent (#PCDATA) >
<!ATTLIST Extent
          name CDATA #REQUIRED
          default CDATA #IMPLIED
          nearestValue (0 | 1) "0">

<!-- Attribution indicates the provider of a Layer or collection of Layers.
The provider's URL, descriptive title string, and/or logo image URL may be
supplied.  Client applications may choose to display one or more of these
items.  A format element indicates the MIME type of the logo image located at
LogoURL.  The logo image's width and height assist client applications in
laying out space to display the logo. -->
<!ELEMENT Attribution ( Title?, OnlineResource?, LogoURL? )>
<!ELEMENT LogoURL (Format, OnlineResource) >
<!ATTLIST LogoURL
          width NMTOKEN #REQUIRED
          height NMTOKEN #REQUIRED>

<!-- A Map Server may use zero or more MetadataURL elements to offer detailed,
standardized metadata about the data underneath a particular layer. The type
attribute indicates the standard to which the metadata complies.  Two types
are defined at present: 'TC211' = ISO TC211 19115; 'FGDC' = FGDC CSDGM.  The
format element indicates how the metadata is structured. -->
<!ELEMENT MetadataURL (Format, OnlineResource) >
<!ATTLIST MetadataURL
          type ( TC211 | FGDC ) #REQUIRED>

<!-- A Map Server may use zero or more Identifier elements to list ID numbers
or labels defined by a particular Authority.  For example, the Global Change
Master Directory (gcmd.gsfc.nasa.gov) defines a DIF_ID label for every
dataset.  The authority name and explanatory URL are defined in a separate
AuthorityURL element, which may be defined once and inherited by subsidiary
layers.  Identifiers themselves are not inherited. -->

<!ELEMENT AuthorityURL (OnlineResource) >
<!ATTLIST AuthorityURL
          name NMTOKEN #REQUIRED >
<!ELEMENT Identifier (#PCDATA) >
<!ATTLIST Identifier
          authority CDATA #REQUIRED >

<!-- A Map Server may use DataURL to offer more information about the data
underneath a particular layer. While the semantics are not well-defined, as
long as the results of an HTTP GET request against the DataURL are properly
MIME-typed, Viewer Clients and Cascading Map Servers can make use of this. -->
<!ELEMENT DataURL (Format, OnlineResource) >

<!-- A Map Server may use FeatureListURL to point to a list of the features
represented in a Layer. -->
<!ELEMENT FeatureListURL (Format, OnlineResource) >

<!-- A Style element lists the name by which a style is requested and a
human-readable title for pick lists, optionally (and ideally) provides a
human-readable description, and optionally gives a style URL. -->
<!ELEMENT Style ( Name, Title, Abstract?,
                  LegendURL*, StyleSheetURL?, StyleURL? ) >

<!-- A Map Server may use zero or more LegendURL elements to provide an
image(s) of a legend relevant to each Style of a Layer.  The Format element
indicates the MIME type of the legend. Width and height attributes are
provided to assist client applications in laying out space to display the
legend. -->
<!ELEMENT LegendURL (Format, OnlineResource) >
<!ATTLIST LegendURL
          width NMTOKEN #REQUIRED
          height NMTOKEN #REQUIRED>

<!-- StyleSheeetURL provides symbology information foreach Style of a Layer. -->
<!ELEMENT StyleSheetURL (Format, OnlineResource) >

<!-- A Map Server may use StyleURL to offer more information about the data or
symbology underlying a particular Style. While the semantics are not
well-defined, as long as the results of an HTTP GET request against the
StyleURL are properly MIME-typed, Viewer Clients and Cascading Map Servers can
make use of this. A possible use could be to allow a Map Server to provide
legend information. -->
<!ELEMENT StyleURL (Format, OnlineResource) >

<!-- Minimum and maximum scale hints for which it is appropriate to
display this layer. -->
<!ELEMENT ScaleHint EMPTY>
<!ATTLIST ScaleHint
          min CDATA #REQUIRED
          max CDATA #REQUIRED>

As an aid to understanding and a guide for implementation, this Annex contains example XML which is valid according to the DTD in Annex A.1, WMS Capabilities DTD. Implementers should consult the main body of the specification document and the DTD to ensure compliance rather than editing this XML without full understanding, as the examples herein apply only to a limited range of cases. This is a copy of <http://www.digitalearth.gov/wmt/xml/capabilities_1_1_1.xml>.

<?xml version='1.0' encoding="UTF-8" standalone="no" ?>
<!-- The DTD (Document Type Definition) given here must correspond to the version number declared in the WMT_MS_Capabilities element below. -->
<!DOCTYPE WMT_MS_Capabilities SYSTEM
 "http://www.digitalearth.gov/wmt/xml/capabilities_1_1_1.dtd"
 [
 <!-- Vendor-specific elements are defined here if needed. -->
 <!-- If not needed, just leave this EMPTY declaration.  Do not
  delete the declaration entirely. -->
 <!ELEMENT VendorSpecificCapabilities EMPTY>
 ]>  <!-- end of DOCTYPE declaration -->

<!-- Note: this XML is just an EXAMPLE that attempts to show all
required and optional elements for illustration.  Consult the Web Map
Service 1.1.0 specification and the DTD for guidance on what to actually
include and what to leave out. -->

<!-- The version number listed in the WMT_MS_Capabilities element here must
correspond to the DTD declared above.  See the WMT specification document for
how to respond when a client requests a version number not implemented by the
server. -->
<WMT_MS_Capabilities version="1.1.1" updateSequence="0">
<!-- Service Metadata -->
<Service>
  <!-- The WMT-defined name for this type of service -->
  <Name>OGC:WMS</Name>
  <!-- Human-readable title for pick lists -->
  <Title>Acme Corp. Map Server</Title>
  <!-- Narrative description providing additional information -->
  <Abstract>WMT Map Server maintained by Acme Corporation.  Contact: webmaster@wmt.acme.com.  High-quality maps showing roadrunner nests and possible ambush locations.</Abstract>
  <KeywordList>
    <Keyword>bird</Keyword>
    <Keyword>roadrunner</Keyword>
    <Keyword>ambush</Keyword>
  </KeywordList>
  <!-- Top-level web address of service or service provider.  See also OnlineResource
  elements under <DCPType>. -->
  <OnlineResource xmlns:xlink="http://www.w3.org/1999/xlink" xlink:type="simple"
   xlink:href="http://hostname/" />
  <!-- Contact information -->
  <ContactInformation>
    <ContactPersonPrimary>
      <ContactPerson>Jeff deLaBeaujardiere</ContactPerson>
      <ContactOrganization>NASA</ContactOrganization>
    </ContactPersonPrimary>
    <ContactPosition>Computer Scientist</ContactPosition>
    <ContactAddress>
      <AddressType>postal</AddressType>
      <Address>NASA Goddard Space Flight Center, Code 933</Address>
      <City>Greenbelt</City>
      <StateOrProvince>MD</StateOrProvince>
      <PostCode>20771</PostCode>
      <Country>USA</Country>
    </ContactAddress>
    <ContactVoiceTelephone>+1 301 286-1569</ContactVoiceTelephone>
    <ContactFacsimileTelephone>+1 301 286-1777</ContactFacsimileTelephone>
    <ContactElectronicMailAddress>delabeau@iniki.gsfc.nasa.gov</ContactElectronicMailAddress>
  </ContactInformation>
  <!-- Fees or access constraints imposed. -->
  <Fees>none</Fees>
  <AccessConstraints>none</AccessConstraints>
</Service>
<Capability>
  <Request>
    <GetCapabilities>
      <Format>application/vnd.ogc.wms_xml</Format>
      <DCPType>
        <HTTP>
          <Get>
            <!-- The URL here for invoking GetCapabilities using HTTP GET
            is only a prefix to which a query string is appended. -->
            <OnlineResource xmlns:xlink="http://www.w3.org/1999/xlink"
             xlink:type="simple"
             xlink:href="http://hostname:port/path" />
          </Get>
          <Post>
            <!-- The URL here for invoking GetCapabilities using HTTP POST
            includes the complete address to which a query would be sent in
            XML format.  This is here for future expansion; no POST encoding
	    has yet been defined. -->
            <OnlineResource xmlns:xlink="http://www.w3.org/1999/xlink"
             xlink:type="simple"
             xlink:href="http://hostname:port/path" />
          </Post>
        </HTTP>
      </DCPType>
    </GetCapabilities>
    <GetMap>
      <Format>image/gif</Format>
      <Format>image/png</Format>
      <Format>image/jpeg</Format>
      <DCPType>
        <HTTP>
          <Get>
            <!-- The URL here for invoking GetCapabilities using HTTP GET
            is only a prefix to which a query string is appended. -->
            <OnlineResource xmlns:xlink="http://www.w3.org/1999/xlink"
             xlink:type="simple"
             xlink:href="http://hostname:port/path" />
          </Get>
        </HTTP>
      </DCPType>
    </GetMap>
    <GetFeatureInfo>
      <Format>application/vnd.ogc.gml</Format>
      <Format>text/plain</Format>
      <Format>text/html</Format>
      <DCPType>
        <HTTP>
          <Get>
            <OnlineResource xmlns:xlink="http://www.w3.org/1999/xlink"
             xlink:type="simple"
             xlink:href="http://hostname:port/path" />
          </Get>
        </HTTP>
      </DCPType>
    </GetFeatureInfo>
    <DescribeLayer><!--optional; used only by SLD-enabled WMS-->
      <Format>application/vnd.ogc.gml</Format>
      <DCPType>
        <HTTP>
          <Get>
            <OnlineResource xmlns:xlink="http://www.w3.org/1999/xlink"
             xlink:type="simple"
             xlink:href="http://hostname:port/path" />
          </Get>
        </HTTP>
      </DCPType>
    </DescribeLayer>
  </Request>
  <Exception>
    <Format>application/vnd.ogc.se_xml</Format>
    <Format>application/vnd.ogc.se_inimage</Format>
    <Format>application/vnd.ogc.se_blank</Format>
  </Exception>
  <!-- Any text or markup is allowed here, as required to describe
       vendor-specific capabilities.  Please define elements and attributes
       in the DOCTYPE declaration at the start of the document. -->
  <!-- This example is empty because no VSPs were defined in preamble -->
  <VendorSpecificCapabilities />
  <!-- Place-holder for Styled Layer Descriptor (SLD)-enabled WMSes.
       This element is absent for a basic WMS. -->
  <UserDefinedSymbolization SupportSLD="1" UserLayer="1" UserStyle="1"
	RemoteWFS="1" />
  <Layer>
    <Title>Acme Corp. Map Server</Title>
    <SRS>EPSG:4326</SRS> <!-- all layers are available in at least this SRS -->
    <AuthorityURL name="DIF_ID">
      <OnlineResource xmlns:xlink="http://www.w3.org/1999/xlink" xlink:type="simple"
       xlink:href="http://gcmd.gsfc.nasa.gov/difguide/whatisadif.html" />
    </AuthorityURL>
    <Layer>
      <!-- This parent layer has a Name and can therefore be requested from a Map Server, yielding a map of all subsidiary layers. -->
      <Name>ROADS_RIVERS</Name> 
      <Title>Roads and Rivers</Title>
      <!-- See the spec to learn how some characteristics are inherited by
           subsidiary layers. -->
      <SRS>EPSG:26986</SRS> <!-- An additional SRS for this layer --> 
      <LatLonBoundingBox minx="-71.63" miny="41.75" maxx="-70.78" maxy="42.90"/>
      <!-- The optional resx and resy attributes below indicate the X and Y spatial
           resolution in the units of that SRS. -->
      <!-- The EPSG:4326 BoundingBox duplicates some of the info in LatLonBoundingBox
           and is therefore optional, but using it here allows the additional
           resolution attributes. -->
      <BoundingBox SRS="EPSG:4326"
       minx="-71.63" miny="41.75" maxx="-70.78" maxy="42.90" resx="0.01" resy="0.01"/>
      <BoundingBox SRS="EPSG:26986"
       minx="189000" miny="834000" maxx="285000" maxy="962000" resx="1" resy="1" />
      <!-- Optional Title, URL and logo image of data provider. -->
      <Attribution>
        <Title>State College University</Title>
        <OnlineResource xmlns:xlink="http://www.w3.org/1999/xlink" xlink:type="simple"
         xlink:href="http://www.university.edu/" />
        <LogoURL width="100" height="100">
          <Format>image/gif</Format>
          <OnlineResource xmlns:xlink="http://www.w3.org/1999/xlink"
           xlink:type="simple"
           xlink:href="http://www.university.edu/icons/logo.gif" />
        </LogoURL>
      </Attribution>
      <!-- Identifier whose meaning is defined in an AuthorityURL element -->
      <Identifier authority="DIF_ID">123456</Identifier>
      <FeatureListURL>
        <Format>application/vnd.ogc.se_xml"</Format>
        <OnlineResource xmlns:xlink="http://www.w3.org/1999/xlink" xlink:type="simple"
         xlink:href="http://www.university.edu/data/roads_rivers.gml" />
      </FeatureListURL>
      <Style>
        <Name>USGS</Name>
        <Title>USGS Topo Map Style</Title>
        <Abstract>Features are shown in a style like that used in USGS topographic maps.</Abstract>
        <!-- A picture of a legend for a Layer in this Style -->
        <LegendURL width="72" height="72">
          <Format>image/gif</Format>
          <OnlineResource xmlns:xlink="http://www.w3.org/1999/xlink"
           xlink:type="simple"
           xlink:href="http://www.university.edu/legends/usgs.gif" />
        </LegendURL>
        <!-- An XSL stylesheet describing how GML feature data will rendered to create
             a map of this layer. -->
        <StyleSheetURL>
          <Format>text/xsl</Format>
          <OnlineResource xmlns:xlink="http://www.w3.org/1999/xlink"
           xlink:type="simple"
           xlink:href="http://www.university.edu/stylesheets/usgs.xsl" />
        </StyleSheetURL>
      </Style>
      <ScaleHint min="4000" max="35000"></ScaleHint>
      <Layer queryable="1">
	<Name>ROADS_1M</Name> 
	<Title>Roads at 1:1M scale</Title>
	<Abstract>Roads at a scale of 1 to 1 million.</Abstract>
	<KeywordList>
          <Keyword>road</Keyword>
          <Keyword>transportation</Keyword>
          <Keyword>atlas</Keyword>
	</KeywordList>
	<Identifier authority="DIF_ID">123456</Identifier>
        <!-- Metadata specific to this particular layer.  The same FGDC metadata is offered in two formats. -->
	<MetadataURL type="FGDC">
          <Format>text/plain</Format>
          <OnlineResource xmlns:xlink="http://www.w3.org/1999/xlink"
           xlink:type="simple"
           xlink:href="http://www.university.edu/metadata/roads.txt" />
        </MetadataURL>
	<MetadataURL type="FGDC">
           <Format>text/xml</Format>
           <OnlineResource xmlns:xlink="http://www.w3.org/1999/xlink"
            xlink:type="simple"
            xlink:href="http://www.university.edu/metadata/roads.xml" />
        </MetadataURL>
        <!-- In addition to the Style specified in the parent Layer, this Layer is available in this style. -->
	<Style>
	  <Name>ATLAS</Name>
	  <Title>Road atlas style</Title>
	  <Abstract>Roads are shown in a style like that used in a commercial road atlas.</Abstract>
        <LegendURL width="72" height="72">
          <Format>image/gif</Format>
          <OnlineResource xmlns:xlink="http://www.w3.org/1999/xlink"
           xlink:type="simple"
           xlink:href="http://www.university.edu/legends/atlas.gif" />
        </LegendURL>
	</Style>
      </Layer>
      <Layer queryable="1">
	<Name>RIVERS_1M</Name>
	<Title>Rivers at 1:1M scale</Title>
	<Abstract>Rivers at a scale of 1 to 1 million.</Abstract>
	<KeywordList>
          <Keyword>river</Keyword>
          <Keyword>canal</Keyword>
          <Keyword>waterway</Keyword>
	</KeywordList>
      </Layer>
    </Layer>
    <Layer queryable="1">
      <Title>Weather Forecast Data</Title>
      <SRS>EPSG:4326</SRS> <!-- harmless repetition of common SRS -->
      <LatLonBoundingBox minx="-180" miny="-90" maxx="180" maxy="90" />
      <!-- These weather data are available daily from 1999-01-01 through
           2000-08-22. -->
      <Dimension name="time" units="ISO8601" />
      <Extent name="time" default="2000-08-22">1999-01-01/2000-08-22/P1D</Extent>
      <Layer>
	<Name>Clouds</Name> 
	<Title>Forecast cloud cover</Title>
      </Layer>
      <Layer>
	<Name>Temperature</Name> 
	<Title>Forecast temperature</Title>
      </Layer>
      <Layer>
	<Name>Pressure</Name> 
	<Title>Forecast barometric pressure</Title>
        <!-- Pressure is available at several elevations.
         EPSG:5030 is WGS 84 ellipsoid, units in metres.
         Pressure is also available at several times.
         NOTE: first list all Dimension elements, then all Extent elements. -->
         <Dimension name="time" units="ISO8601" />
         <Dimension name="elevation" units="EPSG:5030" />
         <Extent name="time" default="2000-08-22">1999-01-01/2000-08-22/P1D</Extent>
         <Extent name="elevation" default="0" nearestValue="1">0,1000,3000,5000,10000</Extent>
      </Layer>
    </Layer>
    <!-- Example of a layer which is a static map of fixed
         size which the server cannot subset or make transparent -->
    <Layer opaque="1" noSubsets="1" fixedWidth="512" fixedHeight="256">
      <Name>ozone_image</Name>
      <Title>Global ozone distribution (1992)</Title>
      <LatLonBoundingBox minx="-180" miny="-90" maxx="180" maxy="90" />
      <Extent name="time" default="1992">1992</Extent>
    </Layer>
    <!-- Example of a layer which originated from another WMS and has been
         "cascaded" by this WMS. -->
    <Layer cascaded="1">
      <Name>population</Name>
      <Title>World population, annual</Title>
      <LatLonBoundingBox minx="-180" miny="-90" maxx="180" maxy="90" />
      <Extent name="time" default="2000">1990/2000/P1Y</Extent>
    </Layer>
  </Layer>
</Capability>
</WMT_MS_Capabilities>

This annex contains the Service Exception Document Type Definition corresponding to this version of the specification. The DTD may also be found on-line at http://www.digitalearth.gov/wmt/xml/exception_1_1_1.dtd. This section also summarizes the defined exception codes and their meanings.

<!ELEMENT ServiceExceptionReport (ServiceException*)>
<!ATTLIST ServiceExceptionReport version CDATA #FIXED "1.1.1">

<!ELEMENT ServiceException (#PCDATA)>
<!ATTLIST ServiceException code CDATA #IMPLIED>

As an aid to understanding and a guide for implementation, this Annex contains example XML which is valid according to the DTD in Annex A.3, Service Exception DTD. Implementers should consult the main body of the specification document and the DTD to ensure compliance rather than editing this XML without full understanding. This is a copy of http://www.digitalearth.gov/wmt/xml/exception_1_1_0.xml.

<?xml version='1.0' encoding="UTF-8" standalone="no" ?>
<!DOCTYPE ServiceExceptionReport SYSTEM
 "http://www.digitalearth.gov/wmt/xml/exception_1_1_0.dtd">
<ServiceExceptionReport version="1.1.0">
  <ServiceException>
    Plain text message about an error.
  </ServiceException>
  <ServiceException code="InvalidUpdateSequence">
    Another message, this time with a SE code supplied.
  </ServiceException>
  <ServiceException>
    <![CDATA[
    Error in module <foo.c>, line 42

    A message that includes angle brackets in text
    must be enclosed in a Character Data Section
    as in this example.  All XML-like markup is
    ignored except for this sequence of three
    closing characters:
    ]]>
  </ServiceException>
  <ServiceException>
    <![CDATA[
      <Module>foo.c</Module>
      <Error>An error occurred</Error>
      <Explanation>Similarly, actual XML
	can be enclosed in a CDATA section.
	A generic parser will ignore that XML,
	but application-specific software may choose
	to process it.</Explanation>
    ]]>
  </ServiceException>
</ServiceExceptionReport>

This annex specifies the encoding of moments and periods in time. These allow OGC Web Services to support temporal data descriptions and requests. This specification is based on [ISO 8601:1988(E)]; it extends ISO 8601 in the following ways:

This Annex specifies the formats for a moment in time, including years in the current era ("AD") and years before the current era or on geologic timescales, the format for a period of time, and the format for incomplete data fragments.

An extension to [ISO 8601:1988(E)] is used to indicate the time resolution of the available data. The [ISO 8601:1988(E)] format for representing a period of time is used to represent the resolution: Designator P (for Period), number of years Y, months M, days D, time designator T, number of hours H, minutes M, seconds S. Unneeded elements may be omitted.

P1Y

P1M10D

PT2H

PT1.5S

As shown in Table C.1, a list of several times is expressed by separating valid time values with a comma (","). A temporal range, on the other hand, is expressed using an extension to [ISO 8601:1988(E)]. The syntax start/end/period indicates the start time of the data, the ending time, and the time resolution or refresh rate. Data which are refreshed at regular intervals but not archived are represented using time/time/period, where both time values are the same (that of the latest data) and the period indicates the refresh rate.

In some contexts, date information may be incomplete. For example, a GeoParser service that scans text documents for references to locations or times may encounter partial references such as "Tuesday" or "August 30." To allow this time specification to handle such fragments, we include the "truncated representation" allowed by ISO 8601:1988(E), and we add 7 terms to represent days of the week.

This annex describes support for multi-dimensional data in the service metadata and operation request parameters of OGC Web Services. "Dimensions" in this Annex refers to Time, Elevation, and sample dimensions.

The optional element <Dimension> is used in Capabilities XML to declare that one or more dimensional parameters are relevant to the information holdings of that server. The Dimension element does not provide valid values for a Dimension; that is the role of the Extent element described below. A Dimension element includes a required name, a required measurement units specifier, and an optional unitSymbol.

The following is a DTD fragment expression for the Dimension element (from the full DTD in Annex A.1, WMS Capabilities DTD):

<!Element Dimension EMPTY>
<!ATTLIST Dimension
name         ID      #REQUIRED
units        CDATA   #REQUIRED
unitSymbol   CDATA   #IMPLIED>

<Dimension name="wavelength" units="Angstrom" unitSymbol="Ao" />
<Dimension name="temperature" units="Kelvin" unitSymbol="K" />
<Dimension name="pressure_scale_height" units="millibar" unitSymbol="mbar" />
<Dimension name="altitude" units="kilometer" unitSymbol="km" />

Dimension elements shall comply with the following rules:

All Dimensions in a Capabilities XML response are server-defined, with two exceptions. The dimensions named time and elevation are privileged special cases, predefined as follows:

<Dimension name="time" units="ISO8601" />
<Dimension name="elevation" units="EPSG:vertical_datum" />

The units "ISO8601" refers to the Time representation specified in Annex B, Formatting Dates and Times. The units "EPSG:vertical_datum" refers to elevation units and a reference used by one of the European Petroleum Survey Group [ref. 13] vertical datums (use the actual datum number in place of the string "vertical_datum").

Although predefined, a server shall include Time and/or Elevation declarations if it provides extents for those dimensions.

If a server opts to specify elevation or time values in reference systems other than those listed above, it shall use other dimension names instead of "elevation" and "time" (e.g., "altitude" and "date" ).

Dimension declarations are inherited by enclosed Layers, as specified in Section 7.1.4.6, Layer Attributes. A dimension shall not be re-declared using the same name (case-insensitively) with conflicting information.

Having declared the existence of a Dimension, the Capabilities XML response uses corresponding Extent elements to specify the bounds of a geodata object along zero or more independent single dimensions.

Format of Extent element:

<Extent name="dimension_name"
  default="default_value"
multipleValues="0|1" nearestValue="0|1">
extent_value</Extent>

Extent values:

The extent_value string declares what value(s) along the Dimension axis are appropriate for this specific geospatial data object. The extent_value has the syntax shown in Table C.1.

Extent attributes:

Several attributes are defined for the Extent element. Only name is required.

Extent declarations are inherited by enclosed Layers, as specified in Section 7.1.4.6, Layer Attributes. A extent that is re-specified in an enclosed layer using the same name (case-insensitively) replaces the extent that had been inherited.

A resolution value of zero (as in min/max/0) means that the data are effectively at infinitely-fine resolution for the purposes of making requests on the service instance. For instance, an instrument which continuously monitors randomly-occurring data may have no explicitly defined temporal resolution.

<Layer>
  <!-- Declare dimensions in use. Declarations are inherited by enclosed Layers. -->
  <Dimension name="time" units="ISO8601" />
  <Dimension name="temperature" units="Kelvin" unitSymbol="K" />
  <Dimension name="elevation" units="EPSG:5030" />
  ...
  <Layer>  ...
  <!-- Specify extent of Layer. Extents are inherited by enclosed Layers. -->
  <Extent name="time" default="2000-10-17">1996-01-01/2000-10-17/P1D</Extent>
  <Extent name="elevation" default="0">0/10000/100</Extent>
  <Extent name="temperature" default="300">230,300,400</Extent>
  </Layer>
  ...
</Layer>

Requests against multi-dimensional data objects described with <Dimension> and <Extent> require additional parameters to formulate a complete query. This following section specifies how Clients should include dimensional parameters in those operations which support such parameters.

ELEVATION=value
				
            

TIME=value
				
            

VERSION=x.y.z WIDTH=600
REQUEST=map   HEIGHT=300
LAYERS=ozone  TIME=2000-08-03
SRS=EPSG:4326 ELEVATION=1000
BBOX=-180,-90,180,90  FORMAT=image/gif

VERSION=x.y.z WIDTH=600
REQUEST=map   HEIGHT=300
LAYERS=ozone  TIME=2000-07-01/2000-07-31/P1D
SRS=EPSG:4326 ELEVATION=1000
BBOX=-180,-90,180,90  FORMAT=video/mpeg

VERSION=x.y.z    SKIPX=10
REQUEST=coverage SKIPY=10
LAYERS=layer     TIME=2000-07-01/2000-07-31/P1D
SRS=srs_identifier  ELEVATION=0/10000/1000
BBOX=minx,miny,maxx,maxy  FORMAT=application/x-hdf

PROJCS["WGS 84 / Auto UTM",
    GEOGCS["WGS 84",
        DATUM["WGS_1984",
        SPHEROID["WGS_1984", 6378137, 298.257223563]],
        PRIMEM["Greenwich", 0],
        UNIT["Decimal_Degree", 0.0174532925199433]],
    PROJECTION["Transverse_Mercator"],
    PARAMETER["Central_Meridian", ${central_meridian}],
    PARAMETER["Latitude_of_Origin", 0],
    PARAMETER["False_Easting", 500000],
    PARAMETER["False_Northing", ${false_northing}],
    PARAMETER["Scale_Factor", 0.9996],
    UNIT["Meter", 1]]

where

central_meridian = -183.0 + ${zone} * 6.0
zone = min( floor( (${lon0} + 180.0) / 6.0 ) + 1, 60 )
false_northing = (${lat0} >= 0.0) ? 0.0 : 10000000.0

PROJCS["WGS 84 / Auto Tr. Mercator",
    GEOGCS["WGS 84",
        DATUM["WGS_1984",
        SPHEROID["WGS_1984", 6378137, 298.257223563]],
        PRIMEM["Greenwich", 0],
        UNIT["Decimal_Degree", 0.0174532925199433]],
    PROJECTION["Transverse_Mercator"],
    PARAMETER["Central_Meridian", ${central_meridian}],
    PARAMETER["Latitude_of_Origin", 0],
    PARAMETER["False_Easting", 500000],
    PARAMETER["False_Northing", ${false_northing}],
    PARAMETER["Scale_Factor", 0.9996],
    UNIT["Meter", 1]]

where

central_meridian = ${lon0}
false_northing = (${lat0} >= 0.0) ? 0.0 : 10000000.0

PROJCS["WGS 84 / Auto Orthographic",
    GEOGCS["WGS 84",
        DATUM["WGS_1984",
        SPHEROID["WGS_1984", 6378137, 298.257223563]],
        PRIMEM["Greenwich", 0],
        UNIT["Decimal_Degree", 0.0174532925199433]],
    PROJECTION["Orthographic"],
    PARAMETER["Central_Meridian", ${central_meridian}],
    PARAMETER["Latitude_of_Origin", ${latitude_of_origin}],
    UNIT["Meter", 1]]

where

central_meridian = ${lon0}
latitude_of_origin = ${lat0}

PROJCS["WGS 84 / Auto Equirectangular",
    GEOGCS["WGS 84",
        DATUM["WGS_1984",
        SPHEROID["WGS_1984", 6378137, 298.257223563]],
        PRIMEM["Greenwich", 0],
        UNIT["Decimal_Degree", 0.0174532925199433]],
    PROJECTION["Equirectangular"],
    PARAMETER["Central_Meridian", ${central_meridian}],
    PARAMETER["Latitude_of_Origin", 0],
    PARAMETER["Standard_Parallel_1", ${standard_parallel}],
    UNIT["Meter", 1]]

where

central_meridian = ${lon0}
standard_parallel = ${lat0}

A Unified Modeling Language (UML) representation of web mapping that is independent of the HTTP Distributed Computing Platform treated in this implementation specification will be produced. The UML will be published either within this document or a separate Part 0. The needed material is expected to emerge in part from UML work undertaken by the OGC Documentation Subcommittee. As part of that work, and following on technical advances by the OGC Web Services testbed, Figure 1 (OGC Web Services Architecture diagram) of the present document will be revised.

The specification will be expanded with a Part 2 to support operation requests using HTTP POST.

The Capabilities XML Document Type Definition (DTD) will be replaced by an XML Schema document that more precisely dictates the format of the Capabilities XML.

The Capabilities XML will be revised, replacing some ad hoc constructs with a unified treatment of layer identification that includes metadata about the nature of the map information, its source, appropriate scales for display, and any cascading, caching, transformation or value-adding processes that may have occurred.

Annex B, Formatting Dates and Times of the present document introduces several extensions to ISO 8601:1988(E) to allow years before 0001 and to express the periodicity of data over a certain interval. The revised standard ISO 8601:2000 eliminates the need for those extensions. Annex B, Formatting Dates and Times will be revised to take account of these changes in ISO 8601.