defining horizontal and vertical coordinate reference systems (CRS)

[zdefne-usgs]

Horizontal (geospatial_bounds_crs)

The coordinate reference system (CRS) of the point coordinates in the geospatial_bounds attribute. This CRS may be 2-dimensional or 3-dimensional, but together with geospatial_bounds_vertical_crs, if that attribute is supplied, must match the dimensionality, order, and meaning of point coordinate values in the geospatial_bounds attribute. If geospatial_bounds_vertical_crs is also present then this attribute must only specify a 2D CRS. EPSG CRSs are strongly recommended. If this attribute is not specified, the CRS is assumed to be EPSG:4326. Examples: 'EPSG:4979' (the 3D WGS84 CRS), 'EPSG:4047'.

In ISO 19115-2: The MD_CRS from ISO 19111 is not included in ISO 19115

Vertical (geospatial_bounds_vertical_crs)

The vertical coordinate reference system (CRS) for the Z axis of the point coordinates in the geospatial_bounds attribute. This attribute cannot be used if the CRS in geospatial_bounds_crs is 3-dimensional; to use this attribute, geospatial_bounds_crs must exist and specify a 2D CRS. EPSG CRSs are strongly recommended. There is no default for this attribute when not specified. Examples: 'EPSG:5829' (instantaneous height above sea level), "EPSG:5831" (instantaneous depth below sea level), or 'EPSG:5703' (NAVD88 height).

In ISO 19115-2: /gmi:MI_Metadata/gmd:identificationInfo/gmd:MD_DataIdentification/gmd:extent/gmd:EX_Extent/gmd:verticalElement/gmd:EX_VerticalExtent/gmd:verticalCRS

[zdefne-usgs]

Horizontal coordinate system
Because we don't have "geospatial_bounds_vertical_crs" the CRS is assumed to be EPSG:4326 (?)

Vertical coordinate system

<gmd:extent>
  <gmd:EX_Extent id="boundingExtent">
    <gmd:geographicElement>
      <gmd:EX_GeographicBoundingBox id="boundingGeographicBoundingBox">
        <gmd:extentTypeCode>
          <gco:Boolean>1</gco:Boolean>
        </gmd:extentTypeCode>
        <gmd:westBoundLongitude>
          <gco:Decimal>-74.43636499745051</gco:Decimal>
        </gmd:westBoundLongitude>
        <gmd:eastBoundLongitude>
          <gco:Decimal>-74.0033391193193</gco:Decimal>
        </gmd:eastBoundLongitude>
        <gmd:southBoundLatitude>
          <gco:Decimal>39.44520325543955</gco:Decimal>
        </gmd:southBoundLatitude>
        <gmd:northBoundLatitude>
          <gco:Decimal>40.14055802120193</gco:Decimal>
        </gmd:northBoundLatitude>
      </gmd:EX_GeographicBoundingBox>
    </gmd:geographicElement>
    <gmd:temporalElement>
      <gmd:EX_TemporalExtent id="boundingTemporalExtent">
        <gmd:extent>
          <gml:TimePeriod gml:id="timePeriod_id">
            <gml:beginPosition>2012-03-01T00:30:00Z</gml:beginPosition>
            <gml:endPosition>2012-10-01T00:00:00Z</gml:endPosition>
          </gml:TimePeriod>
        </gmd:extent>
      </gmd:EX_TemporalExtent>
    </gmd:temporalElement>
    <gmd:verticalElement>
      <gmd:EX_VerticalExtent>
        <gmd:minimumValue>
          <gco:Real>-0</gco:Real>
        </gmd:minimumValue>
        <gmd:maximumValue>
          <gco:Real>-25</gco:Real>
        </gmd:maximumValue>
        <gmd:verticalCRS xlink:href="http://www.epsg-registry.org/export.htm?gml=urn:ogc:def:datum:EPSG::5103" xlink:title="North American Vertical Datum 1988" xlink:actuate="onRequest"/>
      </gmd:EX_VerticalExtent>
    </gmd:verticalElement>
  </gmd:EX_Extent>
</gmd:extent>

[zdefne-usgs]

Need more feed back on this...