RDF ordering is pretty ugly. I don't know of anyone using it. There are two possible uses of ordering:
1. To specify the order of different properties. For example, height before length 2. To specify the order of different values for the same property In some situations it will be possible to resolve use case 2 into use case 1 by creating different properties. In Michel's example it would mean creating Line1, Line2, etc. properties and, possibly, for convenience, making them all subproperty of Line. More than one design patterns are possible for the use case 1. If the order of the properties is always the same irrespective of how they are used, you can just specify it as annotation on the property by creating a special annotation property - could be "order" with a numerical value range similar to the composite:indedx http://composing-the-semantic-web.blogspot.com/2007/07/composite-design-patt ern-in-rdfowl.htmlor sequence reference pointing to the next item. If the order is contextual (for example, for a rectangle height goes before length, for a trapezoid, length goes before height), the more complex modeling patterns are needed. One of them is actually implemented in TBC and you can examine it. Form customization in TBC captures the order of the properties in the form. You can take a look at .tbc files to understand how it is done. Irene Polikoff -----Original Message----- From: [email protected] [mailto:[email protected]] On Behalf Of Arthur Keen Sent: Thursday, March 12, 2009 9:44 AM To: [email protected] Subject: [tbc-users] Re: 'Order' in OWL? I have the same issue with keeping topological entities ordered, more specifically keeping points on a contour ordered. The Jena tutorial describes RDF containers including "SEQ is an ordered collection". ...but I am not sure how to do this in TopBraid or even if this is the right way to do it in OWL. http://jena.sourceforge.net/tutorial/RDF_API/#ch-Containers Containers RDF defines a special kind of resources for representing collections of things. These resources are called containers. The members of a container can be either literals or resources. There are three kinds of container: * a BAG is an unordered collection * an ALT is an unordered collection intended to represent alternatives * a SEQ is an ordered collection A container is represented by a resource. That resource will have an rdf:type property whose value should be one of rdf:Bag, rdf:Alt or rdf:Seq, or a subclass of one of these, depending on the type of the container. The first member of the container is the value of the container's rdf:_1 property; the second member of the container is the value of the container's rdf:_2 property and so on. The rdf:_nnn properties are known as the ordinal properties. On Mar 12, 2009, at 4:30 AM, Michel Bohms wrote: > > Dear All, > > I am currently experimenting with the use of SPIN/Sparql when mapping > one ontology to another. > > The source ontology is typically a semantic one (say a Wall class with > height, width and length properties). > The target ontology is typically a less-semantic cad-like explicit > shape representation one (a BoundaryREPresentation (BREP), with > points, lines, faces etc.). > > The target ontology is based on existing schema/data structures like > coming from ISO STEP or IAI, initiatives often not yet OWL but other > languages like EXPRESS. > > In such other languages it is typically possible to model 'order' like > a Face has 4 ordered Lines: Line1, Line2, Line3, Line4, which when > connected in that order give the boundary of the face. > > Now comes my issue: how would I model this 'order' in an OWL-version > of such model? How can I put an order to my taget individuals in my > object properties? In the past I have heard reasons for OWL not > supporting order, being not really a semantic aspect. > > All ideas welcome, thx, Michel Bohms > > --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "TopBraid Composer Users" group. To post to this group, send email to [email protected] To unsubscribe from this group, send email to [email protected] For more options, visit this group at http://groups.google.com/group/topbraid-composer-users?hl=en -~----------~----~----~----~------~----~------~--~---
