Nomenclature

The UDF has a standard set of terminology associated with it to describe various features both in its design and its usage. Prior to reading any of the UDF documentation it is worthwile to familiarize yourself with the few terms below as they are used throughout.

MakeRc

The make configuration file through which users can customize the compile and link options used on their system when building either core libraries or applications. The custimization may allow for greater speed and efficiency through the use of compile flags which target the local cpu as well as generic compiler optimization.

Lineage

PMEIV

Each measurement within the UDF is identified by its lineage. This is a 5 field ID often termed the measurement PMEIV (PROJECT, MISSION, EXPERIMENT, INSTRUMENT, VIRTUAL INSTRUMENT). In reverse order this consists of: the acronym of the UDF definition in which the measurement is contained, the UDF acronym for the instrument from which the measurement was obtained, the UDF acronym for the experiment containg the defined instrument, the UDF acronym for the mission (satellite) on which the experiment is being flown, and the UDF acronym for the project of which the mission is a part.

Plot Interface Definition File (PIDF)

One of the four files in the UDF file system. This file is the primary interface between external programs and the UDF. It contains a variety of information including which measurements are available under a UDF definition, what units their data can be returned in and the algorithms pass to the generic conversion routine to achive those units.

Sensor

A measurement stored under the UDF format is called a sensor. A sensor can hold 1, 2 or 3 dimensional data. A 1-D sensor is denoted as a scalar sensor, a 2-D as an array sensor, and a 3-D as a matrix sensor.

Sensor Set

A block of measurements within a UDF data record in the UDF data file.

Virtual Instrument

This the UDF acronym assigned to a UDF definition. The term virtual instrument is used to indicate that the measurements contained within the definition may be only a subset of the total data stream associated with the instrument from which the measurements are obtained.

UDF Data File

One of the four files in the UDF file system. This file holds the measurement data defined under a UDF definition.

UDF Header File

One of the four files in the UDF file system. This file holds the dynamic roadmap used when parsing the UDF data file as well slowly or non-varying data such as the year and day of year associated with the measurements.

Virtual Instrument Definition File (VIDF)

One of the four files in the UDF file system. This files holds the the description of a UDF definition including what meaasurements are included in the descriptions and all calibration parametes which are associated with those measurements.