Spatial Extent

Element Description

The Spatial Extent element describes the geographic extent or coverage of data provided in a file or in a data collection.  

Best Practices

In the CMR, spatial extent of data may be specified as a horizontal spatial domain, a vertical spatial domain, or an orbital spatial domain. The type of spatial domain being described in the metadata is identified via the 'Spatial Coverage Type' element. There are five different options for 'Spatial Coverage Type' in CMR. These include:

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

Certain metadata elements are associated with each of the Spatial Coverage Types. These are summarized below:

Horizontal 

Horizontal spatial extent is the area of the surface of the Earth which is covered by data. For horizontal spatial extent, the coverage must be specified as either Cartesian or Geodetic via the Coordinate System element:

SpatialExtent/HorizontalSpatialDomain/Geometry/CoordinateSystem:

Choice of:

• CARTESIAN: 
• GEODETIC: 

Furthermore, there are four different ways to express the horizontal spatial coverage. Only one of these options may be selected (i.e. you can't provide both a bounding rectangle and a point). However - each one of these options may be repeated as many times as necessary (i.e. multiple bounding rectangles may be provided) :

(1) Point

• Point location as expressed in latitude and longitude coordinates. Multiple points may be provided if necessary.

(2) Bounding Rectangle

• A rectangle as expressed with 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 whose shape/edges is defined by latitude/ longitude point pairs. The more points are provided, the more detailed the polygon will be. Exclusive zones within the polygon may also be identified (e.g. a small polygon within a larger polygon is specified as not being included in the spatial extent of the data set). 

(4) Line

• A width-less line expressed as latitude/ longitude point pairs. Multiple points/ line vertices may be provided to express a complex line.   

Vertical

Vertical spatial extent can be used to describe data with a vertical component. The type of vertical spatial extent being described must be selected from a controlled list of options via the Type element:

SpatialExtent/VerticalSpatialDomain/Type:

Choice of:

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

Once a Type is selected, it is required to provide an accompanying value in the SpatialExtent/VerticalSpatialDomain/Value field. For example, the Type selected could be "Maximum Altitude" and the corresponding Value could be "50 KM".

Orbital 

When data is systematically collected via a satellite, it may provide useful to describe the orbital characteristics of the satellite platform. The Orbital spatial coverage type includes the following sub-elements, most of which are required if providing orbital information:

Swath Width: R

Period: R

Inclination Angle: R

Number of Orbits: R

Start Circular Latitude:    

Examples:

Value needed for translations:

The following value is needed by the CMR to translate older non UMM compliant records to and from the UMM and other supported specifications where non required elements are considered required but no valid is given.  This is needed partly because the CMR still allows a non UMM compliant record to be ingested with warnings.

NOT PROVIDED - It is necessary for this value to exist so that the CMR can translate older non UMM compliant records into the latest UMM specification where CollectionProgress is required. This value should not be used by metadata providers.

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