verticalDatum new object

[stansmith907]

Schema rules for verticalDatum: "the reference frame or system from which vertical distances (altitudes or depths) are measured."

Rules:

• optional

Definitions:

• datumIdentifier: {identifier} "the identification given to the surface taken as the surface of reference from which altitudes or depths are measured."
• datumName: (string) "the identification given to the surface taken as the surface of reference from which altitudes or depths are measured."
• encodingMethod: {string} "the means used to encode the altitudes."
• isDepthSystem: {Boolean} "true if depth system, false if altitude system."
• verticalResolution: {real} "the minimum distance possible between two adjacent altitude or depth values, expressed in units of measure."
• unitOfMeasure: {string} "units of measure for altitude or depth measurements."

Rules:

• datumIdentifier required (conditional)
• datumName required (conditional)
• encodingMethod required (conditional)
• isDepthSystem required (conditional)
• verticalResolution required (conditional)
• unitOfMeasure required (conditional)
  Note: FGDC does not handle datumIdentifier and thus requires all the remaining elements. ISO can only handle the identifier for the datum. So, condition is either identifier or all the other elements.

mdJson:

{
   "spatialReferenceSystem": [
      {
         "referenceSystemType": "MD_ReferenceSystemTypeCode",
         "referenceSystemIdentifier": {},
         "referenceSystemParameterSet": {
            "projection": {},
            "ellipsoid": {},
            "verticalDatum": {
               "datumIdentifier": {},
               "datumName": "",
               "encodingMethod": "",
               "isDepthSystem": false,
               "verticalResolution": 9.9,
               "unitOfMeasure": ""
            }
         }
      }
   ]
}

FGDC mapping:
Altitude and depth datum are assigned to different elements in FGDC, combined in mdJson with an isDepthSystem element to distinguish between the two (default = false).

<metadata>
  <spref>
    <horizsys></horizsys>
    <vertdef>
      <altsys>
        <altdatum></altdatum>
        <altres></altres>
        <altunits></altunits>
        <altenc></altenc>
      </altsys>
      <depthsys>
        <depthdn></depthdn>
        <depthres></depthres>
        <depthdu></depthdu>
        <depthem></depthem>
      </depthsys>
    </vertdef>
  </spref>
</metadata>

ISO 19115-2 mapping:
These elements map to ISO 19115-2 only as MD_CRS.datum.identifier.

	<gmd:referenceSystemInfo>
		<gmd:MD_CRS>
			<gmd:datum>
				<gmd:RS_Identifier>
					<gmd:code>
						<gco:CharacterString></gco:CharacterString>
					</gmd:code>
				</gmd:RS_Identifier>
			</gmd:datum>
		</gmd:MD_CRS>
	</gmd:referenceSystemInfo>

ISO 19115-3 mapping:
Does not map to ISO 19115-1/3. This information was removed to ISO 19111 ( I do not have documentation at this time ).

[jlblcc]

Do we have access to ISO 19111 docs?

[stansmith907]

Per our discussion datumName was dropped. This changed requirements to ...

• datumIdentifier required
• datumIdentifier and all other element required for FGDC