- From: Antoine Isaac <aisaac@few.vu.nl>
- Date: Sun, 26 May 2013 16:39:59 +0200
- To: <public-openannotation@w3.org>
Hi, This actually relates to recommendations I had made a long time ago for simplifying the conventions. Not all had been followed then, but of course I'm happy that someone's giving a try at it again :-) So: +1 for not having any graphical distinction between the object vs. datatype properties +1 for the UML stuff. In fact I believe that it's not really needed to have a different form of arrow for the rdf:type one. There's already the label... Antoine > > Straight vs Curved: Agreed. It doesn't make a significant difference most of the time, and the resource vs literal is sufficient to easily visually distinguish. > > Open Arrows: Right, it's not class related but not instantiation. I'm happy to remove the UML comment. (And as a non substantive change, will do so now) > > Rob > > > > > On Fri, May 24, 2013 at 3:26 PM, Bob Morris <morris.bob@gmail.com <mailto:morris.bob@gmail.com>> wrote: > > OK, I understand that the graphical conventions [1] in the Feb 2013 > spec are purely informative, and about the doc, not the model. But I > have come to decide that in publications it would be helpful to stay > as close to the graphics of the spec doc as feasible. In attempting to > do so, I have---so far-- one minor whine and one whimper. > > Whine: I see no powerful reason to distinguish object predicates' > arrows from datatype predicates' arrows by whether they are straight > or curved. That distinction should be guided by the layout > constraints in the diagram. For both cases, it is easy to find > oneself forced into graphical ugliness by sticking to the convention. > Among the consequences are wasteful extra white space needed when > straight arrows are "required" and silly trivial curves when curved > ones are "required". By "required" I only mean, "attempting to follow > the documentation conventions." Besides all that, the two types are > already distinguished by the shape of their targets---ellipses for > objects, lozenges for literals. So it would be nice if the > documentation were simply silent on the matter of curves or straight > arrows. It wouldn't even require changing the pictures. > > Whimper: It's a stretch to say "Class instantiation (rdf:type) is > depicted as a straight black line with white arrow head, following > UML." Most (all?) UML systems produce diagrams in which the > equivalent of rdf:type is denoted with ":" in the label of a box > depicting the object and its properties. There are no arrows for this > particular UML association between instances and classes. Other > associations between any UML objects are denoted with solid lines, > and, if those associations are directional, with open arrowheads. > Open arrows are generally (always?) reserved for the "generalizes" > association, useful in specifying a class hierarchy. I like the > triangular headed arrow convention for rdf:type, because it's an easy > to find graphical signpost that let's you ignore the predicate name > when it doesn't matter. But crediting it to UML makes me more, not > less, confused, especially in the face of other UML reserved words, > like "association" that are also used differently in UML. I would > remove "following UML" from [1]. > > Bob Morris > > [1] http://www.openannotation.org/spec/core/index.html#Examples > -- > Robert A. Morris > > Emeritus Professor of Computer Science > UMASS-Boston > 100 Morrissey Blvd > Boston, MA 02125-3390 > > IT Staff > Filtered Push Project > Harvard University Herbaria > Harvard University > > email: morris.bob@gmail.com <mailto:morris.bob@gmail.com> > web: http://efg.cs.umb.edu/ > web: http://wiki.filteredpush.org > http://www.cs.umb.edu/~ram > === > The content of this communication is made entirely on my > own behalf and in no way should be deemed to express > official positions of The University of Massachusetts at Boston or > Harvard University. > >
Received on Sunday, 26 May 2013 14:40:36 UTC