DECODE Process

To access this process:

Data ribbon >> Data Tools >> Set Value >> Decode.
View the Find Command screen, select DECODE and click Run.
Enter "DECODE" into the Command Line and press <ENTER>.

See this process in the Command Table.

Process Overview

Decode a named field of the input file through a dictionary file, writing a new output file containing all the fields of the input file, plus the new decoded field, which is given the name supplied in symbolic field *TEXT.

A dictionary file is a database file containing two fields; CODE and TEXT. Each may be either an alphanumeric or a numeric field. There should be only one value of each CODE field; if there are multiple values, then only the first one will be taken. The dictionary file must be sorted on the CODE field. If it is not, use the SORT process prior to using the DECODE process. The maximum length of the CODE field (if alphanumeric) is 40 characters, and the maximum length of the TEXT field (if alphanumeric) is 80 characters. The CODE field should match in type and length the field to be decoded.

The dictionary CODE field is matched against the field specified as symbolic field *CODE. If the value matches, then the *TEXT field in the output file will contain the value from the TEXT dictionary field. If the *CODE field is not matched, the *TEXT field is set to the *CODE field, as closely as field lengths permit. If the fields are different types (i.e. not both numeric or alphanumeric), then the *TEXT field is set to absent data (if numeric field) or blank (if alpha field).

Typical uses of the DECODE process are to convert geological coding to a text string, or to convert from one language to another. The method is, however, very general, and may be used for example to decode one set of numbers from another; for example, to set slope angles as a function of a numeric rock type.

The dictionary file is first read into your application's virtual array, and is searched using a binary chop search. This is why it must be sorted on the CODE field.

Note: the default value of the *TEXT field in the output file is set to the default value of the TEXT field in the dictionary. This can be used to advantage, for example when setting up slope angles in an orebody model from a rocktype code using a dictionary. The default value of the TEXT field (representing the SLOPE angle) should be set to the required default SLOPE field value.

Input Files

Name	Description	I/O Status	Required	Type
IN	File to be decoded. This contains the field CODE (real name specified below) which is translated through the dictionary file DICT matching with the CODE field, and writing the equivalent TEXT field from the dictionary to the output file as field TEXT.	Input	Yes	Undefined
DICT	Dictionary file (fields CODE and TEXT). There should be only one occurrence of each CODE value. This file MUST be sorted on CODE.	Input	Yes	Dictionary

Output Files

Name	I/O Status	Required	Type	Description
OUT	Output	Yes	Undefined	Decoded file. An exact copy of the input file with the decoded field TEXT added.

Fields

Name	Description	Source	Required	Type	Default
CODE	Field to be translated in input file.	IN	Yes	Character	Undefined
TEXT	Field holding translated text, on output file.	OUT	Yes	Character	Undefined

Examples

!DECODE &IN(FILE1), &OUT(FILE2), &DICT(DICT), *CODE(ROCK), *TEXT(LITHOL)

The 4-character alphanumeric field rock in file1 is decoded through the dictionary file dict, with the translation going into field lithol in file file2. The dictionary file contains two alphanumeric fields; CODE, with a 4-character rocktype classification code, and TEXT with an English description, which is placed into field lithol in file2.

!DECODE &IN(MODEL), &OUT(MODEL1), &DICT(SLOPDICT), *CODE(ROCK), *TEXT(SLOPE)

The orebody model file model has a numeric rocktype field ROCK. This is decoded through the slope angle dictionary slopdict to give a new slope angle field SLOPE in the output model file model1. The dictionary would contain the CODE and TEXT fields; the CODE field gives the possible values of ROCK (sorted in order of ROCK) and the TEXT field gives the associated SLOPE angles required. The default value of the dictionary TEXT field will become the default SLOPE angle to be used by PITEVA where there are no cells.

Error and Warning Messages

Message	Description
Error: unable to open or read from...	Unable to access or read from the specified input file. Fatal; the process is exited without creating an output file.
Error: Error during reading Dictionary...	Empty input or dictionary file. Fatal; the process is exited without creating an output file. Fatal; the process is exited without creating an output file.
Error: TEXT field already exists in input file...	TEXT field already exists in the input file or CODE field name was not found in the input file. Fatal; the process is exited without creating an output file.
Warning: CODE value has already been specified. Additional references will be ignored	Code field already specified so duplicate references (following original) are ignored - non-fatal.
Error: missing mandatory field	A missing field, normally TEXT or CODE could not be found. Fatal; the process is exited without creating an output file.
Error: Failed to open input file	An input file could not be found at the specified location. Fatal; the process is exited without creating an output file.
Error: Error during file copy	An error occurred copying from the input to the output file. Fatal; the process is exited without creating an output file.
Error: CODE field in input and output files differ in type	The field definition for the CODE attribute in both input and output files is not identical (e.g. different type or implicit/explicit mismatch). Fatal; the process is exited without creating an output file.