Dap:Attribute Extension Example 5

From OPeNDAP Documentation

1 Example 5

Where we take the "mingling" too far and it breaks. We attempt to multiply wrap the value of a dap:Attribute with a wcs:Title element:

               <Attribute name="standard_name" type="String">
                   <value><ows:Title>surface_eastward_sea_water_velocity</ows:Title></value>
               </Attribute>

And this breaks our ability to easily use automation to extract the (in this example DAP2) content

1.1 Source XML

<?xml version="1.0" encoding="UTF-8"?> 
<Dataset name="200803061600_HFRadar_USEGC_6km_rtv_SIO.nc"
        xmlns="http://xml.opendap.org/ns/DAP2"
        xmlns:wcs="http://www.opengis.net/wcs/1.1"
        xmlns:ows="http://www.opengis.net/ows/1.1"
        xmlns:owcs="http://www.opengis.net/wcs/1.1/ows"
        xmlns:gml="http://www.opengis.net/gml/3.2"
        xmlns:xlink="http://www.w3.org/1999/xlink"
       >

   <wcs:CoverageDescription>
       <ows:Title>Near-Real Time Surface Ocean Velocity</ows:Title>
       <ows:Abstract>CoverageDescription generated by OPeNDAP WCS UseCase 2.0</ows:Abstract>
       <wcs:Identifier>coverage/200803061600_HFRadar_USEGC_6km_rtv_SIO.nc</wcs:Identifier>
       <wcs:Domain>
           <wcs:SpatialDomain>
               <ows:BoundingBox crs="urn:ogc:def:crs:EPSG::4326">
                   <ows:LowerCorner>-97.8839 21.736</ows:LowerCorner>
                   <ows:UpperCorner>-57.2312 46.4944</ows:UpperCorner>
               </ows:BoundingBox>
           </wcs:SpatialDomain>
           <wcs:TemporalDomain>
               <gml:timePosition>2008-03-27T16:00:00.000Z</gml:timePosition>
           </wcs:TemporalDomain>
       </wcs:Domain>
       <wcs:Range>

           <Attribute name="NC_GLOBAL" type="Container">
               <Attribute name="Conventions" type="String">
                   <value>CF-1.1</value>
               </Attribute>
               <Attribute name="title" type="String">
                   <value>Near-Real Time Surface Ocean Velocity</value>
               </Attribute>
               <Attribute name="institution" type="String">
                   <value>Scripps Institution of Oceanography</value>
               </Attribute>
               <Attribute name="source" type="String">
                   <value>Surface Ocean HF-Radar</value>
               </Attribute>
               <Attribute name="history" type="String">
                   <value>12-Mar-2008 22:26:19: NetCDF file created</value>
               </Attribute>
           </Attribute>

           <Grid name="u">
               <wcs:Field>
                   <ows:Abstract>Eastward component of a 2D sea surface velocity vector.</ows:Abstract>
                   <wcs:Identifier>u</wcs:Identifier>
                   <wcs:Definition>
                       <ows:AnyValue/>
                   </wcs:Definition>
                   <wcs:NullValue>-32768</wcs:NullValue>
                   <owcs:InterpolationMethods>
                       <owcs:DefaultMethod>nearest</owcs:DefaultMethod>
                   </owcs:InterpolationMethods>
               </wcs:Field>
               <Attribute name="standard_name" type="String">
                   <value><ows:Title>surface_eastward_sea_water_velocity</ows:Title></value>
               </Attribute>
               <Attribute name="units" type="String">
                   <value>m s-1</value>
               </Attribute>
               <Attribute name="_FillValue" type="Int16">
                   <value>-32768</value>
               </Attribute>
               <Attribute name="scale_factor" type="Float32">
                   <value>0.009999999776</value>
               </Attribute>
               <Attribute name="ancillary_variables" type="String">
                   <value>DOPx</value>
               </Attribute>
               <Array name="u">
                   <Int16/>
                   <dimension name="time" size="1"/>
                   <dimension name="lat" size="460"/>
                   <dimension name="lon" size="701"/>
               </Array>
               <Map name="time">
                   <Int32/>
                   <dimension name="time" size="1"/>
               </Map>
               <Map name="lat">
                   <Float32/>
                   <dimension name="lat" size="460"/>
               </Map>
               <Map name="lon">
                   <Float32/>
                   <dimension name="lon" size="701"/>
               </Map>
           </Grid>

           <dataBLOB href=""/>
       </wcs:Range>

       <wcs:SupportedCRS>urn:ogc:def:crs:EPSG::4326</wcs:SupportedCRS>
       <wcs:SupportedFormat>netcdf-cf1.0</wcs:SupportedFormat>
       <wcs:SupportedFormat>dap2.0</wcs:SupportedFormat>
   </wcs:CoverageDescription>

</Dataset>

1.2 Namespace Blocking Transform

Returns all elements NOT in the DAP2 namespace. Or in other words, discard elements in the DAP2 namespace:

<xsl:stylesheet version="1.0"
               xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
               xmlns:dap="http://xml.opendap.org/ns/DAP2" >
   <xsl:output method='xml' version='1.0' encoding='UTF-8' indent='yes'/>

   <xsl:strip-space elements="*" />

   <xsl:template match="*">
       <xsl:choose>
           <xsl:when test="namespace-uri()!='http://xml.opendap.org/ns/DAP2'">
               <xsl:copy >
                   <xsl:call-template name="textAndattributes" />
                   <xsl:apply-templates />
               </xsl:copy>
           </xsl:when>
           <xsl:otherwise>
               <xsl:apply-templates />
           </xsl:otherwise>
       </xsl:choose>
   </xsl:template>

   <xsl:template  match="@*|text()" />

   <xsl:template name="textAndattributes" ><xsl:copy-of select="text()|@*" /></xsl:template>

</xsl:stylesheet>

1.3 Result

Produces a correct wcs:CoverageDescrition element:
<?xml version="1.0" encoding="UTF-8"?>
<wcs:CoverageDescription xmlns="http://xml.opendap.org/ns/DAP2" xmlns:wcs="http://www.opengis.net/wcs/1.1"
                        xmlns:ows="http://www.opengis.net/ows/1.1"
                        xmlns:owcs="http://www.opengis.net/wcs/1.1/ows"
                        xmlns:gml="http://www.opengis.net/gml/3.2"
                        xmlns:xlink="http://www.w3.org/1999/xlink">
  <ows:Title>Near-Real Time Surface Ocean Velocity</ows:Title>
  <ows:Abstract>CoverageDescription generated by OPeNDAP WCS UseCase 2.0</ows:Abstract>
  <wcs:Identifier>coverage/200803061600_HFRadar_USEGC_6km_rtv_SIO.nc</wcs:Identifier>
  <wcs:Domain>
     <wcs:SpatialDomain>
        <ows:BoundingBox crs="urn:ogc:def:crs:EPSG::4326">
           <ows:LowerCorner>-97.8839 21.736</ows:LowerCorner>
           <ows:UpperCorner>-57.2312 46.4944</ows:UpperCorner>
        </ows:BoundingBox>
     </wcs:SpatialDomain>
     <wcs:TemporalDomain>
        <gml:timePosition>2008-03-27T16:00:00.000Z</gml:timePosition>
     </wcs:TemporalDomain>
  </wcs:Domain>
  <wcs:Range>
     <wcs:Field>
        <ows:Title>surface_eastward_sea_water_velocity</ows:Title>
        <ows:Abstract>Eastward component of a 2D sea surface velocity vector.</ows:Abstract>
        <wcs:Identifier>u</wcs:Identifier>
        <wcs:Definition>
           <ows:AnyValue/>
        </wcs:Definition>
        <wcs:NullValue>-32768</wcs:NullValue>
        <owcs:InterpolationMethods>
           <owcs:DefaultMethod>nearest</owcs:DefaultMethod>
        </owcs:InterpolationMethods>
     </wcs:Field>
  </wcs:Range>
  <wcs:SupportedCRS>urn:ogc:def:crs:EPSG::4326</wcs:SupportedCRS>
  <wcs:SupportedFormat>netcdf-cf1.0</wcs:SupportedFormat>
  <wcs:SupportedFormat>dap2.0</wcs:SupportedFormat>
</wcs:CoverageDescription>

1.4 Namespace Passing Transform

Returns all elements IN the DAP2 namespace:

<xsl:stylesheet version="1.0"
               xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
               xmlns:dap="http://xml.opendap.org/ns/DAP2" >
   <xsl:output method='xml' version='1.0' encoding='UTF-8' indent='yes'/>

   <xsl:strip-space elements="*" />
   
   <xsl:template match="*">
       <xsl:choose>
           <xsl:when test="namespace-uri()='http://xml.opendap.org/ns/DAP2'">
               <xsl:copy >
                   <xsl:call-template name="textAndattributes" />
                   <xsl:apply-templates />
               </xsl:copy>
           </xsl:when>
           <xsl:otherwise>
               <xsl:apply-templates />
           </xsl:otherwise>
       </xsl:choose>
   </xsl:template>

   <xsl:template  match="@*|text()" />

   <xsl:template name="textAndattributes" ><xsl:copy-of select="text()|@*" /></xsl:template>
 
</xsl:stylesheet>

1.5 Result

Fails to get the value of the dap:Attribute named standard_name whose value was encapsulated in an ows:Title element:

<?xml version="1.0" encoding="UTF-8"?>
<Dataset xmlns="http://xml.opendap.org/ns/DAP2" xmlns:wcs="http://www.opengis.net/wcs/1.1"
        xmlns:ows="http://www.opengis.net/ows/1.1"
        xmlns:owcs="http://www.opengis.net/wcs/1.1/ows"
        xmlns:gml="http://www.opengis.net/gml/3.2"
        xmlns:xlink="http://www.w3.org/1999/xlink"
        name="200803061600_HFRadar_USEGC_6km_rtv_SIO.nc">
  <Attribute name="NC_GLOBAL" type="Container">
     <Attribute name="Conventions" type="String">
        <value>CF-1.1</value>
     </Attribute>
     <Attribute name="title" type="String">
        <value>Near-Real Time Surface Ocean Velocity</value>
     </Attribute>
     <Attribute name="institution" type="String">
        <value>Scripps Institution of Oceanography</value>
     </Attribute>
     <Attribute name="source" type="String">
        <value>Surface Ocean HF-Radar</value>
     </Attribute>
     <Attribute name="history" type="String">
        <value>12-Mar-2008 22:26:19: NetCDF file created</value>
     </Attribute>
  </Attribute>
  <Grid name="u">
     <Attribute name="standard_name" type="String">
        <value/>
     </Attribute>
     <Attribute name="units" type="String">
        <value>m s-1</value>
     </Attribute>
     <Attribute name="_FillValue" type="Int16">
        <value>-32768</value>
     </Attribute>
     <Attribute name="scale_factor" type="Float32">
        <value>0.009999999776</value>
     </Attribute>
     <Attribute name="ancillary_variables" type="String">
        <value>DOPx</value>
     </Attribute>
     <Array name="u">
        <Int16/>
        <dimension name="time" size="1"/>
        <dimension name="lat" size="460"/>
        <dimension name="lon" size="701"/>
     </Array>
     <Map name="time">
        <Int32/>
        <dimension name="time" size="1"/>
     </Map>
     <Map name="lat">
        <Float32/>
        <dimension name="lat" size="460"/>
     </Map>
     <Map name="lon">
        <Float32/>
        <dimension name="lon" size="701"/>
     </Map>
  </Grid>
  <dataBLOB href=""/>
</Dataset>