Side Looking Airborne Radar (SLAR) Mosaics Data Dictionary

Acquisition Date

• Field Definition:  The acquisition date refers to the year, month, and day the data were acquired.

               Values:
               Format: YYYY/MM/DD
               YYYY = Year
               MM = Month
               DD = Day
 

Acquisition Facility

• Field Definition:  The company or facility that acquired the imagery.
   

Coordinates - Decimal Degrees

• Field Definition:  The latitude and longitude are provided in decimal degrees for the following fields:

                 Values:      
                 Scene Center Latitude and Longitude
                 Northeast (NE) Corner Latitude and Longitude
                 Northwest (NW) Corner Latitude and Longitude
                 Southeast (SE) Corner Latitude and Longitude
                 Southwest (SW) Corner Latitude and Longitude

                 Latitude Format Decimal Degrees: -90.000 through 90.000
                 Longitude Format Decimal Degrees: -180.000 through 180.000

                 Number of decimal places will vary by dataset – check collection in EE.
 

Coordinates - Degrees, Minutes, Seconds

• Field Definition:  The latitude and longitude are provided in degrees, minutes, and seconds for the following fields:

                 Values:
                 Scene Center Latitude and Longitude
                 Northeast (NE) Corner Latitude and Longitude
                 Northwest (NW) Corner Latitude and Longitude
                 Southeast (SE) Corner Latitude and Longitude
                 Southwest (SW) Corner Latitude and Longitude

                Longitude Format:
                DDDMMSS.SSH
                DDD = Degree(s) with a range of 0 through 180
                MM = Minute(s) with a range of 0 through 59
                SS.SS = Second(s) with a range of 0 through 59.99
                H = Hemisphere with E for east and W for west

                Latitude Format:
                DDMMSS.SSH
                DD = Degree(s) with a range of 0 through 90
                MM = Minutes(s) with a range of 0 through 59
                SS.SS = Second(s) with a range of 0 through 59.99
                H = Hemisphere with N for north and S for south
 

Depression Angle

• Field Definition:  This field identifies the depression angle (degrees) of the radar signal.
   

Entity ID

• Field Definition:  This field is used to identify data by assigning a unique series of letters and numbers to an image.

               Format:
               DDAPPPPPPFFFFFF
               Where DD = Data set Designator = SI
               A = Agency, where 1 = USGS
               PPPPPP = Project Code
               FFFFF - File Number

              Example:
              SI1REPA00820898
 

Frequency

• Field Definition:  This field identifies the frequency (gigahertz) or wavelength (centimeters) used by the signal.

              Values:
              X = 2.40 - 3.75 cm wavelength; 8 - 12.5 GHz frequency
              L = 15 - 30 cm wavelength; 1 - 2 GHz frequency
 

Look Direction

• Field Definition:  Since the microwaves travel at the speed of light in air, the timing of each portion of the returned signal establishes its image position in the range or look direction (perpendicular to the flightline).

              Values:
              N = North
              S = South
              E = East
              W = West
 

Map Name

• Field Definition:  The name of the corresponding 1:250,000-scale map for the scene.
   

Mosaic Scale

• Field Definition:  The scale of the mosaic is the ratio of a distance on the map to the corresponding distance on the ground.

              Example:
              250 = 1:250,000-scale map
 

Project

• Field Definition:  The project assigned to this mosaic.
   

Range

• Field Definition:  The range (or cross track) is a measure of the “line-of-sight’ distance from the radar to the target.

               Example:
               Near
               Mix
               Far
 

Sensor

• Field Definition:  The sensor used to acquire the data such as Real Aperture or Synthetic Aperture.

               Values:
               S26 = Real Aperture
               S27 = Synthetic Aperture

Signal

• Field Definition:  The polarization of the radar signal such as HH = horizontally transmitted and horizontally returned.