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
Geodetic Model is used to describe data that has been georeferenced to a datum, which is a well defined ellipsoidal/spherical representation of the Earth. There are many different standard datums. Knowing which datum the data is encoded in is extremely useful for processing/manipulating the data using GIS software. Sub-elements under Geodetic Model are summarized below:
- Horizontal Datum Name: The name of the model used to correspond coordinates provided in the data to the surface of the Earth. Also referred to as a Geodetic Datum. The Geodetic Datum is a more localized/ specialized version of a simple Ellipsoid (see below). It is recommended that EPSG Datum names be used.
- Ellipsoid Name: An elliptical or spherical shape representing the Earth. An Ellipsoid's shape can be defined by a major axis (longer axis) and a minor axis (shorter axis). There are standard names for different Ellipsoids - it is recommended that EPSG Ellipsoid names be used.
- Semi Major Axis: The radius of the major axis of the Ellipsoid. The length and units of the Semi Major Axis should be defined by the Ellipsoid standard.
- Denominator Of Flattening Ratio: The ratio of the Ellipsoid's major axis to the difference between the major and the minor axis. Also referred to as the Inverse Flattening ratio. The smaller the ratio, the 'flatter' or more oval-like the Ellipsoid's shape will be.
(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.
- Datum Name: The identification given to the level surface taken as the surface of reference from which measurements are compared.
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"
Element Specification
Providing the Spatial Representation Information element is optional (Cardinality: 0..1)
Model | Element | Type | Constraints | Required? | Cardinality | Notes |
---|---|---|---|---|---|---|
UMM-C | SpatialRepresentationInfo/SpatialCoverageType | String | 1 - 80 characters | Yes | 1 | |
UMM-C | SpatialRepresentationInfo/VerticalCoordinateSystem/AltitudeSystemDefinition/DatumName | String | 1 - 80 characters | No | 0..1 | |
UMM-C | SpatialRepresentationInfo/VerticalCoordinateSystem/AltitudeSystemDefinition/DistanceUnits | Enumeration | HectoPascals Kilometers Millibars | No | 0..1 | |
UMM-C | SpatialRepresentationInfo/VerticalCoordinateSystem/AltitudeSystemDefinition/EncodingMethod | No | 0..1 | |||
UMM-C | SpatialRepresentationInfo/VerticalCoordinateSystem/AltitudeSystemDefinition/Resolutions | Array | No | 0..* | ||
UMM-C | SpatialRepresentationInfo/VerticalCoordinateSystem/DepthSystemDefinition/DatumName | String | 1 - 80 characters | No | 0..1 | |
UMM-C | SpatialRepresentationInfo/VerticalCoordinateSystem/DepthSystemDefinition/DistanceUnits | Enumeration | Fathoms Feet HectoPascals Meters Millibars | No | 0..1 | |
UMM-C | SpatialRepresentationInfo/VerticalCoordinateSystem/DepthSystemDefinition/EncodingMethod | No | 0..1 | |||
UMM-C | SpatialRepresentationInfo/VerticalCoordinateSystem/DepthSystemDefinition/Resolutions | Array | No | 0..* | ||
UMM-C | SpatialRepresentationInfo/HorizontalCoordinateSystem/GeodeticModel/HorizontalDatumName | String | 1 - 80 characters | No | 0..1 | |
UMM-C | SpatialRepresentationInfo/HorizontalCoordinateSystem/GeodeticModel/EllipsoidName | String | 1 - 255 characters | No | 0..1 | |
UMM-C | SpatialRepresentationInfo/HorizontalCoordinateSystem/GeodeticModel/SemiMajorAxis | Number | No | 0..1 | ||
UMM-C | SpatialRepresentationInfo/HorizontalCoordinateSystem/GeodeticModel/DenominatorOfFlatteningRatio | Number | No | 0..1 | ||
UMM-C | SpatialRepresentationInfo/HorizontalCoordinateSystem/GeographicCoordinateSystem/GeographicCoordinateUnits | Enumeration | Decimal Degrees Kilometers Meters | No | 0..1 | |
UMM-C | SpatialRepresentationInfo/HorizontalCoordinateSystem/GeographicCoordinateSystem/LatitudeResolution | Number | No | 0..1 | ||
UMM-C | SpatialRepresentationInfo/HorizontalCoordinateSystem/GeographicCoordinateSystem/LongitudeResolution | Number | No | 0..1 | ||
UMM-C | SpatialRepresentationInfo/HorizontalCoordinateSystem/LocalCoordinateSystem/GeoReferenceInformation | String | 1 - 2048 characters | No | 0..1 | |
UMM-C | SpatialRepresentationInfo/HorizontalCoordinateSystem/LocalCoordinateSystem/Description | String | 1 - 2048 characters | No | 0..1 |
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
UMM Version 1.9.0 | Translation Direction | UMM Version 1.10.0 |
---|---|---|
Future Mappings
History
UMM Versioning
Version | Date | What Changed |
---|---|---|
1.12.0 | 01/22/2019 | No changes were made for Spatial Representation Information during the transition from version 1.11.0 to 1.12.0. |
1.11.0 | 11/28/2018 | No changes were made for Spatial Representation Information during the transition from version 1.10.0 to 1.11.0. |
1.10.0 | 05/02/2018 | During the transition from version 1.9.0 to 1.10.0, the sub element 'GeographicCoordinateUnits' was added and enumerated, the sub element 'EncodingMethod' was removed from both 'AltitudeSystemDefinitionType' and 'DepthSystemDefinitionType', and 'VerticalSystemDefinitionType' was replaced with both 'AltitudeSystemDefinitionType' and 'DepthSystemDefinitionType.' Free text strings were also changed to enumeration for the following sub elements within 'AltitudeSystemDefinitionType' and 'DepthSystemDefinitionType': 'AltitudeDistanceUnitsEnum' and 'DepthSystemDefinitionType.' |
1.9.0 |
ARC Documentation
Version | Date | What Changed | Author |
---|---|---|---|
1.0 | 11/16/18 | Recommendations/priority matrix transferred from internal ARC documentation to wiki space |