The following seven VIDF fields provide the sizes of the variable fields in the VIDF. The instances fields are used by the UDF kernel to establish array sizes.
This is a scalar field which provides the number of quality definitions that are listed in the VIDF Data Quality Descriptions field. This is also the maximum value attained by the UDF Header Record quality flag plus one.
Quality flags are returned in each UDF Header Record. They are one byte in length and there is one for each sensor returned in the sensor set for which the header record is valid. There is then a maximum of 256 available quality designations which can be spread over the sensors. Most quality definitions are used for all sensors, however some may be sensor specific. A minimum of one quality flag must be defined in the VIDF. It is possible that not all definitions between quality value 0 and the maximum defined quality value will be used.
NOTE: The VIDF contains one definition per possible quality value from 0 up to the maximum defined value EVEN if the value is NOT used.The field begins with the line format id b followed by an integer specifying the number of quality definitions. An optional comment field may follow.
Sample NUMBER OF QUALITY DEFINITIONS field:b 2 /* Num Quality Definitions */
This is a scalar field containing the number of ancillary data sets defined in this UDF. It is used to determine the array size of the various VIDF fields which deal with ancillary data sets. There can be a maximum of 256 ancillary data sets defined within a UDF definition.
The field begins with the line format id b followed by an integer specifying the number of ancillary data sets. An optional comment field may follow.
Sample NUMBER OF ANCILLARY DATA SETS field:b 8 /* Number Ancillary Sets */
This is a scalar field holding the number of blocks of table definitions which exist in the VIDF. There can be a maximum of 256 defined table blocks.
The field begins with the line format id b followed by an integer specifying the number of VIDF tables. An optional comment field may follow.
Sample NUMBER OF VIDF TABLE DEFINITIONS field:b 14 /* Number of Tables */
This is a scalar field containing the number of blocks of constant definitions which exist in the VIDF. There can be a maximum of 256 defined constant blocks.
The field begins with the line format id b followed by an integer specifying the number of VIDF constants. An optional comment field may follow.
Sample NUMBER OF VIDF CONSTANT DEFINITIONS field:b 14 /* Number of Constants */
This is a scalar field specifying the number of status bytes used in the UDF header records. There can be a maximum of 256 status bytes defined. The value is established when the UDF data set is created and each header record contains the same number of status bytes. The value of this field is used to determine the array size of several VIDF fields which deal with UDF status byte information.
The field begins with the line format id b followed by an integer specifying the number of status bytes. An optional comment field may follow.
Sample NUMBER OF STATUS BYTES field:b 0 /* Number of Status Bytes */
A scalar field indicating whether the pitch angle block is defined in the VIDF. If magnetic field data exists in UDF format for this mission, then the UDF kernal software can make use of it to provide pitch angles for any UDF data for which the measurement normals have been defined in the VIDF constant block. The normal is specfied as a set of three constant definitions, one for each of the vector normal components.
The field begins with the line format id b followed by an integer specifying pitch angle defined flag. This is 0 if the pitch angle block is not defined or a 1 if it is defined. An optional comment field may follow.
Sample PITCH ANGLE DEFINED field:b 0 /* Pitch Angle Defined (No) */
This is an scalar field containing the total number of sensors (measurements) defined in the UDF. It is used to determine the array size of several VIDF fields which deal with UDF sensor specifications. The number of sensors must be greater than 0 since by definition each UDF definition must be based on at least one measurement. The maximum number of UDF sensors is 32767.
Only a subset of the defined measurements may be returned in any given UDF sensor set and it is possible that for a given instrument mode some measurements may never be returned within a given UDF file. The VIDF, however, must hold the definition of any measuements which may be returned under this UDF definition.
The field begins with the line format id b followed by an integer specifying the number of sensors. An optional comment field may follow.
Sample NUMBER OF SENSORS field:s 27 /* Number of Sensors */