Spatial Coverage


Definition

Spatial coverage specifies the geographic and vertical coverage of the data.

  • <Spatial_Coverage_Type> denotes whether the collection's spatial coverage requires horizontal, vertical, or both in the spatial domain and coordinate system definitions.
  • <Granule_Spatial_Representation> denotes the spatial representation of any granules.
  • <Zone_Identifier> denotes the appropriate numeric or alpha code used to identify the various zones in the grid coordinate system.
  • <Geometry> describes the Coordinate_System and geometric bounds of the data.
    • <Coordinate_System> specifies the coordinate system used when producing the data.
    • <Bounding_Rectangle> defines the coordinates of a bounding box and is composed of <Westernmost_Longitude>, <Easternmost_Longitude>, <Northernmost_Latitude>, <Southernmost_Latitude>, and <Center_Point>.
      • Altitude and Depth are included as part of <Bounding_Rectangle>
      • <Minimum_Altitude> is the lower limit of data coverage.
      • <Maximum_Altitude> is the higher limit of data coverage.
      • <Altitude_Unit> the unit of measure for altitude values.
      • <Minimum_Depth> is the upper-most depth of data coverage.
      • <Maximum_Depth> is the lowest depth of data coverage.
      • <Depth_Unit> is the unit of measure for depth values.
    • <Point> specifies the coordinates of data collected at a single point and is composed of <Point_Longitude> and <Point_Latitude>
    • <Line> specifies the coordinates of data collected along a line or transect and consists of two <Point> values and an optional <CenterPoint>.
    • <Polgyon> specifies the coordinates of data contained within a polygon and is composed of a minimum of three <Boundary> points, one or more <Exclusion_Zone>, and a <Center_Point>
  • <Orbit_Parameters> contains fields to describe the orbit of the satellite producing the data, including <Swath_Width>, <Period>, <Inclination_Angle>, <Number_of_Orbits> and <Start_Circular_Latitude>.
  • <Vertical_Spatial_Info> contains the domain value and type for the granule's vertical spatial domain.
    • <Type> describes the type of the area of vertical space covered by the locality
    • <Value> describes the extent of the area of vertical space covered by the granule.
  • <Spatial_Info> is a composite field that stores the reference frame or system from which altitudes (elevations) are measured.
 
Syntax
<Spatial_Coverage>    
   <Spatial_Coverage_Type>A spatial coverage type enumeration</Spatial_Coverage_Type>    
   <Granule_Spatial_Representation>A granule spatial representation enumeration</Granule_Spatial_Representation>    
   <Zone_Identifier>Text</Zone_Identifier>    
   <Geometry>      
      <Coordinate_System>A coordinate system enumeration</Coordinate_System>     
      ...choice of...      
      (1) <Bounding_Rectangle>            
             <Southernmost_Latitude>A decimal degree value between -90.0 and 90.0</Southernmost_Latitude>            
             <Northernmost_Latitude>A decimal degree value between -90.0 and 90.0</Northernmost_Latitude>            
             <Westernmost_Longitude>A decimal degree value between -180.0 and 180.0</Westernmost_Longitude>            
             <Easternmost_Longitude>A decimal degree value between -180.0 and 180.0</Easternmost_Longitude>  
             <Minimum_Altitude>Text</Minimum_Altitude>    
             <Maximum_Altitude>Text</Maximum_Altitude>    
             <Altitude_Unit>Text</Altitude_Unit>    
             <Minimum_Depth>Text</Minimum_Depth>    
             <Maximum_Depth>Text</Maximum_Depth>    
             <Depth_Unit>Text</Depth_Unit>   
             </Bounding_Rectangle>      
       (2) <Point>            
              <Point_Longitude>A decimal degree value between -180.0 and 180.0</Point_Longitude>            
              <Point_Latitude>A decimal degree value between -90.0 and 90.0</Point_Latitude>          
           </Point>      
       (3) <Line>            
           <Point>              
              <Point_Longitude>A decimal degree value between -180.0 and 180.0</Point_Longitude>              
              <Point_Latitude>A decimal degree value between -90.0 and 90.0</Point_Latitude>            
           </Point>            
           <Point>              
              <Point_Longitude>A decimal degree value between -180.0 and 180.0</Point_Longitude>              
              <Point_Latitude>A decimal degree value between -90.0 and 90.0</Point_Latitude>          
           </Point>            
           <Center_Point>              
              <Point_Longitude>A decimal degree value between -180.0 and 180.0</Point_Longitude>              
              <Point_Latitude>A decimal degree value between -90.0 and 90.0</Point_Latitude>            
           </Center_Point>          
           </Line>      
           (4) <Polygon>            
                  <Boundary>              
                     <Point>                
                        <Point_Longitude>A decimal degree value between -180.0 and 180.0</Point_Longitude>                
                        <Point_Latitude>A decimal degree value between -90.0 and 90.0</Point_Latitude>             
                     </Point>            
                   </Boundary>            
                   <Boundary>              
                      <Point>                
                         <Point_Longitude>A decimal degree value between -180.0 and 180.0</Point_Longitude>                
                         <Point_Latitude>A decimal degree value between -90.0 and 90.0</Point_Latitude>              
                      </Point>            
                   </Boundary>            
                   <Boundary>              
                      <Point>                
                         <Point_Longitude>A decimal degree value between -180.0 and 180.0</Point_Longitude>                
                         <Point_Latitude>A decimal degree value between -90.0 and 90.0</Point_Latitude>              
                      </Point>            
                   </Boundary            
                   <Exclusion_Zone>              
                      <Boundary>               
                         <Point>                  
                            <Point_Longitude>A decimal degree value between -180.0 and 180.0</Point_Longitude>                  
                            <Point_Latitude>A decimal degree value between -90.0 and 90.0</Point_Latitude>                
                         </Point>              
                      </Boundary>              
                      <Boundary>                
                         <Point>                  
                            <Point_Longitude>A decimal degree value between -180.0 and 180.0</Point_Longitude>                  
                            <Point_Latitude>A decimal degree value between -90.0 and 90.0</Point_Latitude>                
                         </Point>
                       </Boundary>              
                       <Boundary>                
                          <Point>                  
                             <Point_Longitude>A decimal degree value between -180.0 and 180.0</Point_Longitude>                  
                             <Point_Latitude>A decimal degree value between -90.0 and 90.0</Point_Latitude>                
                          </Point>              
                        </Boundary            
                     </Exclusion_Zone>          
                  </Polygon>    
              <Geometry>    
              <Orbit_Parameters>      
                 <Swath_Width>A decimal value</Swath_Width>      
                 <Period>A decimal value</Period>      
                 <Inclination_Angle>A decimal value</Inclination_Angle>      
                 <Number_of_Orbits>A decimal value</Number_of_Orbits>      
                 <Start_Circular_Latitude>A decimal value</Start_Circular_Latitude>    
              </Orbit_Parameters>    
              <Vertical_Spatial_Info>      
                 <Type>Text</Type>      
                 <Value>Text</Value>    
              </Vertical_Spatial_Info>    
              <Minimum_Altitude>Text</Minimum_Altitude>    
              <Maximum_Altitude>Text</Maximum_Altitude>    
              <Altitude_Unit>Text</Altitude_Unit>    
              <Minimum_Depth>Text</Minimum_Depth>    
              <Maximum_Depth>Text</Maximum_Depth>    
              <Depth_Unit>Text</Depth_Unit>    
              <Spatial_Info>      
                 <Spatial_Coverage_Type>Text</Spatial_Coverage_Type>      
                 <Horizontal_Coordinate_System>        
                    <Geodetic_Model>         
                       <Horizontal_DatumName>Text</Horizontal_DatumName>          
                       <Ellipsoid_Name>Text</Ellipsoid_Name>          
                       <Semi_Major_Axis>A decimal value</Semi_Major_Axis>          
                       <Denominator_Of_Flattening_Ratio>A decimal value</Denominator_Of_Flattening_Ratio>        
                    </Geodetic_Model>        
                    <Geographic_Coordinate_System>          
                       <GeographicCoordinateUnits>Text</GeographicCoordinateUnits>          
                       <LatitudeResolution>A decimal value</LatitudeResolution>          
                       <LongitudeResolution>A decimal value</LongitudeResolution>        
                    </Geographic_Coordinate_System>        
                    <Local_Coordinate_System>          
                       <Description>Text</Description>          
                       <GeoReferenceInformation>Text</GeoReferenceInformation>        
                    </Location_Coordinate_System>      
                 </Horizontal_Coordinate_System>      
                 <TwoD_Coordinate_System>        
                    <TwoD_Coordinate_System_Name>Text</TwoD_Coordinate_System_Name>        
                    <Coordinate1>          
                       <Minimum_Value>A decimal value</Minimum_Value>          
                       <Maximum_Value>A decimal value</Maximum_Value>        
                    </Coordinate1>        
                    <Coordinate2>          
                       <Minimum_Value>A decimal value</Minimum_Value>          
                       <Maximum_Value>A decimal value</Maximum_Value>        
                    </Coordinate2>      
                  </TwoD_Coordiante_System>   
             </Spatial_Info> 
</Spatial_Coverage> 

 

 
Usage

Spatial_Coverage is required and may be repeated; all subfields may only be used once except <Vertical_Spatial_Info>.

  • <Spatial_Coverage_Type> is optional and must be one of the following enumerations: Horizontal, HorizontalVertical, Orbit, Vertical, or Horizon&Vert.
  • <Granule_Spatial_Representation> is required and must be one of the following enumerations: CARTESIAN, GEODETIC, ORBIT, or NO_SPATIAL
  • <Zone_Identifier> is optional.
  • One of <Bounding_Rectangle>, <Point>, <Line>, or <Polygon> is required under Geometry.
    • If <Bounding_Rectangle> is selected, all four latitude/longitude values are required; <Center_Point> is optional.
    • If <Point> is selected, both <Point_Longitude> and <Point_Latitude> are required.
    • If <Line> is selected, at least two <Point> values are required; <Center_Point> is optional.
    • If <Polygon> is selected, at least three <Point> values are required; <Exclusion_Zone> and <Center_Point> are optional.
    • All latitude values should be in decimal degrees between -90.0 and 90.0
    • All longitude values should be in decimal degrees between -180.0 and 180.0
  • <Coordinate_System> must be one of the following enumerations: CARTESIAN or GEODETIC.
  • <Orbit_Parameters> is optional but if used, the following subfields are required and not repeatable: <Swath_Width>, <Period>,

<Start_Circular_Latitude> is optional.

  • <Vertical_Spatial_Info> is optional and repeatable; if used, both subfields are required.
  • <Spatial_Info> is optional
    • <Spatial_Coverage_Type> is required if <Spatial_Info> is used
    • <Horizontal_Coordinate_System> and subfields are optional and not repeatable, with a choice of <Geographic_Coordinate_System> or <Local_Coordinate_System>
    • <TwoD_Coordinate_System> is optional and repeatable;

 

Example

<Spatial_Coverage>
   <Granule_Spatial_Representation>CARTESIAN</Granule_Spatial_Representation>
   <Geometry>
       <Coordinate_System>CARTESIAN</Coordinate_System>
       <Bounding_Rectangle>
             <Southernmost_Latitude>40.0</Southernmost_Latitude>
             <Northernmost_Latitude>85.0</Northernmost_Latitude>
             <Westernmost_Longitude>110.0</Westernmost_Longitude>
             <Easternmost_Longitude>-130.0</Easternmost_Longitude>
       </Bounding_Rectangle>
   </Geometry>
</Spatial_Coverage>

 

This document should be cited as:
Directory Interchange Format (DIF) Writer's Guide, 2018.
Global Change Master Directory.
National Aeronautics and Space Administration.
[https://gcmd.gsfc.nasa.gov/add/difguide/].