What's in a Profile?

CGM files come in four main varieties CGM v1 through to CGM v4 with each of them introducing a new feature.
I am not a graphics Guru but I got involved in this very useful format a few years ago when the standard was increased from CGM v2 to CGM v3. The jump to CGM v3 introduced the functionality of Bezier Curves. Because the viewer could not handle this ‘new’ feature some some graphics were displayed with bits missing. The jump from v3 to the current v4 introduced HotSpots.
Straightforward? You would think so!
Like a number of other standards, CGM graphics need to be tailored to give make them comply with S1000D Business Rules.Some may remember than an earlier post was about Business rules.
Illustration Sizes
Within the S1000D Specification it clearly gives information about the dimensions of 'Board' for sizes of illustration e.g. Full page, Half page, Fold Out etc (see Chapter 3.9.2 Table 1). I have seen illustrations which do not comply with this requirement. This resulted in a group of graphics with all sorts of sizes giving inconsistent display behaviour.
Profile
The specification also indicates which profile should be used. Up to and including Issue 2 Change 1 the specification mandated the use of the ATA profile. The profile is stated as being “ATA CGM profile (GREXCHANGE V2.6 or higher) as defined in ATA iSpec 2200, Chap 5-2-4 – Graphics Exchange”.
The reason that I have mentioned this is because I have encountered some illustrations that have not been exported from Graphic packages using the correct profile attached. The inevitable result of this is that some graphic viewers are not handling the illustrations very well because they do not recognize some of the profile items. A common reason for this change is that the Graphics Package has been upgraded to the latest version and I presume that the previous default settings have lost.
How can you tell how the file has been exported correctly? A quick, but not infallible, test is to open the graphic file in a text editor and view the first part which is more or less in plain text. There should be a mention of a profile in the header area.
Of course, the very latest issue of the S1000D Specification has changed the profile. We wait with interest the outcome of the first publications created to the latest change.