[Nepomuk] Second try: classes and properties for describing excerpts (parts of text, parts of images)

[Jörg Ehrichs]

Hi Sebastian,

I like to jump in on this draft.

I want to describe an excerpt of a book

Either a chapter  or a small portion of the text to annotate it.

> That aside I also think that we should not try to describe where in some
> document our bookmark points to but we should rather properly define the
> excerpt that we want to remember 
Thats what okular is currently doing and is at least easy to implement.

> Thus, we need to describe part of a nie:InformationElement.
> Part of a nfo:PlainTextDocument for example is a piece of text which
> starts at a certain character offset and has a certain length.

And this is what would be great to get the exact data where and what a chapter 
or short portion of a text is.

If I combine it with your draft for the image excerpt I get:

nfo:firstCharacter a rdf:Property ;
  rdfs:domain nfo:TextExcerpt ;
  rdfs:range xsd:integer .  

nfo:lastCharacter a rdf:Property ;
  rdfs:domain nfo:TextExcerpt ;
  rdfs:range xsd:integer .

Which works until someone change the document.
Assuming the xsd:integer is the number of chars before the text starts.

Is there any way describe this without copying the text section into nepomuk 
and still get the proper content even if parts of the document before the 
excerpt changes? 

Otherwise this will most likely make only sense for pdf documents, or rather 
non changeable documents (still fine for my nbib stuff)

At the moment I would stick to okulars way and attach the page number to the 
chapter.

Regards
Joerg