Spatial Information

Element Description

Note: this wiki page is a draft/ work in progress

The Spatial Information element stores the reference frame or system from which horizontal and vertical spatial domains are measured. The horizontal reference frame includes a Geodetic Model, Geographic Coordinates, and Local Coordinates. The Vertical reference frame includes altitudes (elevations) and depths.

Best Practices

Providing Spatial Information is optional, but encouraged. This element can be used to provide horizontal and/or vertical coordinate system information. 

If coordinate system information is provided, then the Spatial Coverage Type field is required. This field is used to specify whether horizontal coordinate system information, vertical coordinate system information, or both will be provided. This field is not currently controlled but there are plans to change it to a controlled vocabulary field in the future:

• Spatial Coverage Type: Denotes whether the spatial coverage of the collection is horizontal, vertical, or horizontal and vertical. While this field is not yet controlled, recommend providing one of the following values for consistency: HORIZONTAL, VERTICAL, HORIZONTAL_VERTICAL
  
  

Horizontal Spatial Information

The following sub-elements can be used to describe Horizontal Coordinate Systems.

There are 3 categories of Horizontal Coordinate Systems including:

(1) Geodetic Model

Sub-elements under Geodetic Model are summarized below:

• • • Horizontal Datum Name: The identification given to the reference system used for defining the coordinates of points.
    • Ellipsoid Name: Identification given to established representation of the Earth's shape. 
    • Semi Major Axis: Radius of the equatorial axis of the ellipsoid.
      
    • Denominator Of Flattening Ratio: The ratio of the Earth's major axis to the difference between the major and the minor.

(2) Geographic Coordinate System

Sub-elements under Geographic Coordinate System are summarized below:

• • • Geographic Coordinate Units: Units of measure used for the geodetic latitude and longitude resolution values (e.g., decimal degrees).
    • Latitude Resolution: The minimum difference between two adjacent latitude values in the Geographic Coordinate System,  expressed in Geographic Coordinate Units of measure, expressed as a two-digit decimal number, e.g., 0.01.
    • Longitude Resolution: The minimum difference between two adjacent longitude values in the Geographic Coordinate System, expressed in Geographic Coordinate Units of measure, expressed as a two-digit decimal number, e.g., 0.01.

(3) Local Coordinate System

Sub-elements under Local Coordinate System are summarized below:

• • • Geo Reference Information: The information provided to register the local system to the Earth (e.g. control points, satellite ephemeral data, and inertial navigation data).
    • Description: A description of the Local Coordinate System and geo-reference information.
      
      

Vertical Spatial Information

The following sub-elements can be used to describe Vertical Coordinate Systems.

There are 2 categories of Vertical Coordinate Systems including:

(1) Altitude System Definition 

Altitude System Definition can be used to describe data with a vertical component that is above-ground. Sub-elements under Altitude System Definition are summarized below:

• • • Datum Name: The identification given to the level surface taken as the surface of reference from which measurements are compared.
    • Distance Units: The units in which altitude measurements are recorded.
    • Encoding Method: 
    • Resolutions: The minimum distance possible between two adjacent values, expressed in distance units of measure for the collection.
      

(2) Depth System Definition

Depth System Definition can be used to describe data with a vertical component that is above-ground. Sub-elements under Altitude System Definition are summarized below:

• • • Datum Name: The identification given to the level surface taken as the surface of reference from which measurements are compared.
      
    • Distance Units: The units in which measurements are recorded.
    • Encoding Method:
    • Resolutions: The minimum distance possible between two adjacent values, expressed in distance units of measure for the collection.

          Examples:

           SpatialCoverageType: "Horizontal"

           VerticalCoordinateSystem/AltitudeSystemDefinition/DatumName: North American Vertical Datum of 1988

           VerticalCoordinateSystem/AltitudeSystemDefinition/DistanceUnits: "Kilometers"

           VerticalCoordinateSystem/AltitudeSystemDefinition/EncodingMethod: "Implicit coordinate"

           HorizontalCoordinateSystem/LocalCoordinateSystem/GeoReferenceInformation: "Control Points"

           VerticalCoordinateSystem/DepthSystemDefinition/DistanceUnits: "HectoPascals"

Metadata Validation and QA/QC

All metadata entering the CMR goes through the below process to ensure metadata quality requirements are met. All records undergo CMR validation before entering the system. The process of QA/QC is slightly different for NASA and non-NASA data providers. Non-NASA providers include interagency and international data providers and are referred to as the International Directory Network (IDN).

Please see the expandable sections below for flowchart details.

Dialect Mappings

UMM Migration

Future Mappings

N/A

N/A

History

UMM Versioning

ARC Documentation