Section 2 - Classification of Metafiles

The CGM*PIP specification establishes the requirements for the communication or interchange of graphical picture data in digital format for use by applications in the petroleum E&P application community. The CGM Profile defined by this specification addresses three interchange components: the metafile, the generator, and the interpreter.

Metafiles conforming to this profile shall identify and classify themselves within each of three categories:

1. level of functionality;

2. colour capability;

3. utilization of the CGM extensions defined in this profile.

   2.1 Level of functionality

   There are four levels of functionality classification for metafiles. These levels are:

   PIP/I		PIP/III
   PIP/II		PIP/IV

   A metafile may be a conforming PIP/I metafile, a conforming PIP/II metafile, a conforming PIP/III metafile, or a conforming PIP/IV metafile. Throughout this document, when PIP is used alone without a modifier, then it applies to all of PIP/I, PIP/II, PIP/III, and PIP/IV.

   Volume 1 of this CGM*PIP specification addresses the specific requirements for PIP/I and PIP/II. This volume addresses the specific requirements for PIP/III and PIP/IV.

   2.2 Colour classification

   There are three levels of colour classification for metafiles. These levels are:

   • monochrome (black & white, or other bi-level);

   • grayscale;

   • full colour.

   A metafile may be a conforming monochrome metafile, or a conforming grayscale metafile, or a conforming full colour metafile. The requirements given in Volume 1, section 4.2.4 through section 4.2.7, of this specification define the meaning and restrictions of each of these three colour classification levels for PIP metafiles.

   2.3 Utilization of extensions

   There are two levels of metafile classification related to extensions:

   • basic: the metafile contains only standard functions of CGM plus the ESCAPEs defined in Volume 1, section 4.3.9 of this profile; none of the ESCAPEs and GDPs defining application community extensions are included.

   • extended: the metafile possibly contains the extended functions, ESCAPE and GDP elements, defined in this profile.

   According to this classification category, a PIP metafile may be a conforming basic PIP metafile or a conforming extended PIP metafile.

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