Spatial Extent

Element Description

The Spatial Extent element describes the geographic coverage of the data. For data collections, the spatial extent describes the area of the Earth that the collection covers. For specific files or granules, the spatial extent describes the area covered by that individual file. 

The Spatial Extent element may also be used to describe vertical coverage of the data and orbital parameters where appropriate. 

Best Practices

In the CMR, there is the option to describe the horizontal, vertical, and orbital spatial coverage of a dataset. The type of spatial coverage being described in the metadata is identified via the 'Spatial Coverage Type' metadata element. There are five different controlled vocabulary options for 'Spatial Coverage Type' in UMM-Common. These include:

• Horizontal
• Vertical
• Orbital
• Horizontal and Vertical
• Orbital and Vertical  

Each spatial extent type requires different information. The information needed for each type is summarized below: 

Horizontal 

Horizontal spatial extent refers to data covering the surface of the Earth. For horizontal spatial extent, a coordinate system must be specified with the choice of either a Cartesian or Geodetic coordinate system:

SpatialExtent/HorizontalSpatialDomain/Geometry/CoordinateSystem:

Choice of:

• CARTESIAN   
• GEODETIC

Please see the Coordinate Systems section of the CMR Data Partner User Guide for instructions on how to assign the appropriate coordinate system.

Furthermore, there are four different options for describing horizontal spatial coverage. Only one of these options may be selected, however, the selected option may be repeated as many times as necessary (e.g. you can't provide a bounding rectangle and a point, but you can provide multiple bounding rectangles). The four options are:

(1) Point

• • A point location defined by a latitude and longitude coordinate. Multiple points may be provided if necessary.

(2) Bounding Rectangle

• • A rectangle defined by a north latitude coordinate, south latitude coordinate, east longitude coordinate, and west longitude coordinate. The north bounding latitude may not exceed 90 degrees, the south bounding coordinate may not be less that -90 degrees, the west bounding coordinate may not be smaller than -180 degrees, and the east bounding coordinate may not exceed 180 degrees. 

(3) GPolygon

• • A polygon defined by latitude/ longitude point pairs. The more points are provided, the more detailed the polygon will be. Exclusion zones within the polygon can also be identified. Please see the CMR Data Partner User Guide for more details. 

(4) Line

• • A width-less line defined by latitude/ longitude point pairs. Multiple points may be provided to express a complex line. Please see the CMR Data Partner User Guide for more details.    

Vertical

Vertical spatial domain can be used to describe the coverage of data with a vertical component. The type of vertical coverage being described in the metadata is identified via the 'Vertical Spatial Domain/ Type' metadata element. There are five different controlled vocabulary options for 'Vertical Spatial Domain/ Type' in UMM-Common. These include:

SpatialExtent/VerticalSpatialDomain/Type:

Choice of:

• Atmosphere Layer
• Maximum Altitude
• Minimum Altitude
• Maximum Depth
• Minimum Depth

Once a Type is selected, an accompanying value in the SpatialExtent/VerticalSpatialDomain/Value field must also be provided. For example, if "Maximum Altitude" was selected as the Type, the corresponding Value could be "50 KM".

Orbital 

When data is collected via a satellite, the Orbit Parameters metadata elements may be used to describe the spatial coverage. Please see the CMR Data Partner User Guide for additional details on how Orbit Parameters are used by the backtrack search algorithm for conducting spatial searches. Orbit Parameters includes the following sub-elements:

Swath Width: The width of the strip of the Earth's surface from which geospatial data are collected by a satellite, in kilometers. Only a number should be provided since the unit of kilometers is implied. If providing orbit parameters, Swath Width is required.  

Period: The time it takes a satellite to complete one complete orbit around the Earth, in decimal minutes. Only a number should be provided since the unit of decimal minutes is implied. If providing orbit parameters, Period is required.  

Inclination Angle: The angle between the equatorial plane of the Earth and the orbital plane of a satellite, in degrees. Only a number should be provided since the unit of degrees is implied. If providing orbit parameters, Inclination Angle is required.

Number of Orbits: "Indicates the number of orbits." 

Start Circular Latitude: "The latitude start of the orbit relative to the equator. This is used by the backtrack search algorithm to treat the orbit as if it starts from the specified latitude. This is optional and will default to 0 if not specified."   

Furthermore, the Granule Spatial Representation element is a required element. This element identifies how the spatial extent is expressed in the granule metadata associated with a collection. The spatial representation used in the collection metadata can be different than what is used in the granule metadata. Granule Spatial Representation is a controlled vocabulary field in the UMM-Common schema and includes the following options: 

• CARTESIAN
• GEODETIC
• ORBIT
• NO_SPATIAL

The granule spatial representation selected at the collection level must be utilized by the granules. Please see the Collection & Granule Spatial Relationships section of the CMR Data Partner User Guide for additional details.

The spatial extent of the granules should always fall within the spatial extent specified in the collection level metadata (and vice versa). It is the responsibility of the metadata author to ensure that collection-granule spatial relationships are compatible.   

Examples:

Choice of one of the following for Horizontal Spatial Domain/ Geometry:

(1) Point

If Point is selected, the cardinality is 1..*

(2) Bounding Rectangle

If BoundingRectangle is selected, the cardinality is 1..*

(3) GPolygon

If GPolygon is selected, the cardinality is 1..*

(4) Line 

If Line is selected, the cardinality is 1..*

Vertical Spatial Domain:

Providing a Vertical Spatial Domain is optional (Cardinality 0..*)

Orbit Parameters:

Providing Orbit Parameters is optional (Cardinality 0..*)

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

<mri:MD_DataIdentification>
  <mri:citation>
    ...
    <mri:status>
      <mri:MD_ProgressCode codeList="{codeListLocation}#MD_ProgressCode"
        codeListValue="onGoing">onGoing</mri:MD_ProgressCode>
    </mri:status>
    ...
  </mri:citation>
</mri:MD_DataIdentification>

"CollectionProgress" : "ACTIVE",

History

UMM Versioning

ARC Documentation