Hi Michael, Yes, I suspected so, these two functions came to my mind too. I am just not too sure about the behaviour of symDifference. But anyway, the main problem is how to deal with the attributes. By applying this to pure geometries, I am still faced with the issue of attaching the attributes of the original geometries to the results. And second, how to generalise for n-FeatureCollections? I was prety sure that this is not going to be a major problem, but once I started looking into it, it seems more complicated then expected.
Cheers, Martin -- Martin Tomko, PhD. Senior Project Manager, Information Infrastructure Design, AURIN Level 5, Architecture Building University of Melbourne VIC 3010 AUSTRALIA T: +61 3 9035 3298 E: [email protected] <mailto:[email protected]> W: www.aurin.org.au <www.aurin.org.au> On 22/11/11 9:53 PM, "Michael Bedward" <[email protected]> wrote: >Hi Martin, > >In terms of JTS operations, this looks like a combination of union and >symDifference. It may be possible to compute both that in one pass >since, looking at the JTS OverlayOp code, the bulk of the processing >is the same but I don't know for sure. Best to pick Martin Davis' >brain on the JTS list I think :) > >Michael > >On 21 November 2011 22:00, Martin Tomko <[email protected]> wrote: >> Hi, >> I am looking for a solution to the following problem (that, I am sure, >>will >> heavily relate on JTS, but I could not come with an easy solution by >>reading >> the docs) : >> I am looking for a function that will mimic my understanding of the >>UNION >> operator in ArcGIS- >> >>http://webhelp.esri.com/arcgisdesktop/9.2/index.cfm?TopicName=How%20Union >>%20%28Analysis%29%20works [first >> figure, right] (do not have the option to test this), as opposed to the >> typical union behaviour from JTS (geometry with a footprint covering all >> argument geometries). So the result is a collection of "shards", small >> geometries. >> I do, however, do not want to end up with overlapping geometries with >> duplicated arguments. As a result, I want a featureCollection with a >>schema >> with all the attributes from the argument featureCOllections. >> Imagine two features with geometries A and B, and attributes X and Y >> f1(A,X) and f2(B,Y)(for instance, see the old JTS Technical >>Specifications >> guide, Figure 10), that overlap. >> More formally: as a result of mymethod(f1,f2), it returns a >> featureCollection (f3,f4,f5), such that f3 = (A-B,X,Y=null), f4=(A >> interesection B, X,Y), f5=(B-A, X=null, Y). >> Now, by preference, this should be able to take as input N>2 >> featureCollections. I can come with all of this, but am looking for the >>best >> way to implement the geometry cracking. >> Anyone has a hint how to approach this? >> Thanks, >> Martin >> >>------------------------------------------------------------------------- >>----- >> All the data continuously generated in your IT infrastructure >> contains a definitive record of customers, application performance, >> security threats, fraudulent activity, and more. Splunk takes this >> data and makes sense of it. IT sense. And common sense. >> http://p.sf.net/sfu/splunk-novd2d >> _______________________________________________ >> Geotools-gt2-users mailing list >> [email protected] >> https://lists.sourceforge.net/lists/listinfo/geotools-gt2-users >> >> > ------------------------------------------------------------------------------ All the data continuously generated in your IT infrastructure contains a definitive record of customers, application performance, security threats, fraudulent activity, and more. Splunk takes this data and makes sense of it. IT sense. And common sense. http://p.sf.net/sfu/splunk-novd2d _______________________________________________ Geotools-gt2-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/geotools-gt2-users
