[GRASS5] adding metadata in GRASS 5.7

Glynn Clements glynn.clements at virgin.net
Fri Sep 3 05:54:31 EDT 2004

Bernhard Reiter wrote:

> > [...]
> > >It does not have to be so detailed, but a lot of the information provided
> > >in this file is essential when this data are to be combined with data
> > >from other sources.
> > >I am sure that for many users it is important to be able to edit
> > >the metadata, especially if one wants to add some comments about
> > >the processing that was done to the file within GRASS. So at
> > >least to keep the capabilities for handling metadata as in 5.3 is
> > >needed.
> > 
> > Why not use the ISO standards for metadata in Grass ?  BTW, it
> > seems that XML is becomming a good choice for structuring this
> > kind od data.
> I am an XML skeptic, because of the hype.
> (XML only solves the character set encoding problem, it does not
> help you with the contents and its sematics.)

It also helps solve structuring issues, e.g. how to delimit sections
and subsections.

> Also I am a meta data standards skeptic because 
> you cannot really enforce a number of fields to be filled all the time.
> But the ability to store annotations (which are meta data in a way)
> is very important. 
> Thus having a place where free text for annotations
> could be saved would be an important advantages.

By using a standardised encapsulation mechanism such as XML, you can
ensure that specific types of information can be identified, without
limiting the type of data which can be stored.

E.g. you can specify that a particular tag is used to delimit
sections, so that an application can add a new section, containing
whatever data it wants, without interfering with existing sections. 

You can define additional tags for common fields such as date, author
etc, a general purpose tag for "human-readable text" which has no
specific interpretation, a tag for unspecified types of potentially
machine-readable data (e.g. <data type="...">blah blah</data>).

Even the most basic schema would be an improvement over the current
history file, which consists of 8 specific fields, each consisting of
a single line of up to 80 characters, plus up to 50 additional
80-character lines with no internal structure.

Glynn Clements <glynn.clements at virgin.net>

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