Information Technology Reference
In-Depth Information
There will be a great deal more said about Semantics in
Chap. 8
, making links to
the Designated Community.
As pointed out in Sect.
7.1
, Representation Information can simply be a hand-
written note or a text document which provides, in sufficient human-readable detail,
enough information for someone to write special software to access the informa-
tion - for example by rendering the image or extracting the numbers a digital object
contains. Providing Representation Information in this way, as has been pointed
out, makes automated use rather difficult at present (at least until there are comput-
ers which can understand the written word as well as a human can). Therefore we
focus in these sections on more formal methods of description.
To define what we might call “good” RepInfo is somewhat difficult to quantify
and depends on many factors, three of which are:
•
what does a piece of RepInfo allow someone to do with the data - what is it used
for? Alternatively, what does one expect people to do with the data, and what
information about the data will enable them to do it?
•
how long into the future does one expect the data and RepInfo to be used?
•
who is supposed to be using the RepInfo and data, and what is their expected
background knowledge?
Of course one is not expected to foresee the future. Instead
one defines the Designated Community and then one sees what
Representation Information is needed now. As time goes by, more
Representation Information will be needed.
However there are good reasons for going a little further, namely
to collect as much Representation Information as possible (within
reason):
•
having machine processable Representation Information facilitates interoperabil-
ity
•
the longer one waits to collect Representation Information the more difficult it
may be, because the experts who used to know the details may have retired
•
it may be of use to other repositories which have a different definition of its
Designated Community.
For example, in Sect.
7.3
, we talk about Structure RepInfo. In doing so we try to
provide an abstract description of what should be contained within it.
In most cases some of the information highlighted in Sect.
7.3.1
can be omitted.
If you assume, for example, that current and future users of it know that the data
uses IEEE floating point values, then there is no need to include that information. It
is really up to you do decide if the RepInfo is adequate for your users now and in
the future.
The detailed definitions of RepInfo given here also provide the reader the
knowledge required to evaluate existing RepInfo. For example, if there is exist-
ing document on Structure RepInfo for some data, then does it contain the types of
information described in Sect.
7.3.1
? If not, then the reader may have to consider
whether or not the existing Structure RepInfo is adequate for current and future use.
