Martin Desruisseaux wrote: > Citing ISO 19107: > > "TransfiniteSet<T> – a possibly infinite set; restricted only to values. > For example, the integers and the real numbers are transfinite sets. > This is actually the usual definition of set in mathematics, but > programming languages restrict the term set to mean finite set." > > Same applies to Map I guess: in mathematic, Map should have been a possibly > infinite map without iterator() or size() methods, and the current > java.util.Map > should have been a subclass of mathematic Map called "FiniteMap". > > This lead me to believe that a mathematic Map object (or TransfiniteMap) > would > have been an appropriate superclass for Coverage, but java.util.Map is not. I > would prefer a MapAdapter class or a "Coverage.mapView(...)" method, where > the > 'mapView(...)' arguments are the envelope and the interval to use for > iterating > over the domain. Then we get a finite map, consistent with java.util.Map > contract. > Thanks Martin this makes a great deal more sense to me; indeed it also lends to my understanding of how a coverage can be defined by an operation. For what is a function by a from parameters to values such as you describe. >> The special case of a discrete coverage is just a collection of homogeneous >> records (not themselves features) which are indexed by geospatial location. >> A discrete coverage is very much like a database table. A discrete >> coverage _can_ provide values for size(), can generate the Sets and >> Collections listed above, and can therefore fully implement the Map >> interface. >> > Right. It would be correct to set "DiscreteCoverage extends Coverage, Map" > (which is allowed for interfaces), but I would avoid "Coverage extends Map". > > However, I may wish to try to implements ISO 19123 as it stand before to add > Map > in the inheritence (i.e. we may want to see how MapAdapter of > Coverage.mapView(...) work in practice, if we implement them). > Lets implemented it as it Stands, and use our knowledge of Java to make the result approachable to the programming community at large.
Question to refine the problem: - Am I to understand then that the "values" for this Map is always Records? - We can always play the statistics game to ask for a "representative sample" in order to produce a normal Java Map out of a Coverage. PS. Cory when you are working with your aggregation functions it may do well to break out this idea of a "representative sample" as a FeatureSouce operation. Cheers, Jody ------------------------------------------------------------------------- Using Tomcat but need to do more? Need to support web services, security? Get stuff done quickly with pre-integrated technology to make your job easier Download IBM WebSphere Application Server v.1.0.1 based on Apache Geronimo http://sel.as-us.falkag.net/sel?cmd=lnk&kid=120709&bid=263057&dat=121642 _______________________________________________ Geotools-devel mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/geotools-devel
