Hi Jeff, I realize that documentation is poor for the graph module, so I would be happy to answer any questions you have. My answers inline.
On Fri, July 28, 2006 4:19 pm, Hyink, Jeffrey \(LCDR\) wrote: > Justin, > > > I appreciate the quick reply. I'll give that a shot asap. I can't find > too much documentation on your module, so maybe you could help with a few > other quick questions...or steer me towards some info. > > 1. When using the LineStringGraphGenerator, will it make nodes in the > graph for every point in the linestring to accomodate intersections with > other roads? Or is an "edge" the entire crooked series of points? I can > see advantages to either implementation. > The latter. To build a graph noded at all intersections you would need to build the graph from the individual line segments. This of course will result in a graph with lots of nodes. You could however "fuse" the graph after (basically removing any degree 2 nodes). There is a utility class called GraphFuser which does just this. > 2. I am looking to "weight" the edges with travel times based on length > of the edge and speed category (a feature attribute). Do you have any > suggestions on how to tease the road or edge length out of a feature, or > do I need to crack open the geometry and do some coordinate math? > So you need to build your graph from features, and not just the underlying geometry. I thought there was a FeatureLineStringGraphGenerator around, but i guess not. It would be pretty trivial to write, it could be a subclass of LineStringGraphGenerator. > 3. I can't see how you are weighting your edges in order to run > Djikstra. I see the Edge class and some of the Djikstra implementation, > but haven't got it figured out yet... How are you creating weighted > d[i,j] edges? There is a "well hidden" interface called EdgeWeighter, it is defined as an inner interface defintion of the DijkstraIterator class. When you create a DijkstraShortestPathFinder you pass one of these types of objects in. > > Thanks much for any help you can provide. Would be glad to repay the > favor somehow if I can get my code up and cooking! > No problem, I am happy to help. And I would definitly be willing to take you up on your offer. Perhaps if the graph module works out for you could contribute a tutorial of some sort. That would be great. > -Jeff > > > > -----Original Message----- > From: Justin Deoliveira [mailto:[EMAIL PROTECTED] > Sent: Fri 7/28/2006 12:51 PM > To: Hyink, Jeffrey (LCDR) > Cc: [email protected] > Subject: Re: [Geotools-gt2-users] Graph module and .src code > > > Hi Jeffrey, > > > You will need to use a LineStringGraphGenerator instead of > BasicLineGraphGenerator. Also, when you call add you will need to pass in > teh geometry of the feature, add( f.getDefaultGeometry() ); > > I thought there was an implementation which worked directly against > features but I dont seem to see it in the repository. > > -Justin > > > On Fri, July 28, 2006 11:24 am, Hyink, Jeffrey (LCDR) wrote: > >> Hello all, >> >> >> >> >> >> I'm about knee deep into developing a program using the GT2 2.2 >> library. I've parsed my way through a couple of the examples and gotten >> enough of the code working to the point that I'm getting dangerous. >> >> >> >> Anyhow, I'm trying to take a set of city roads from a shapefile and use >> the Graph Builder module to turn them into a network(nodes, arcs). >> I'm >> getting a runtime error from the following code in the add() statement. >> >> ... >> >> >> >> BasicLineGraphGenerator lgg = new BasicLineGraphGenerator(); >> >> >> >> FeatureCollection collection = null; >> >> >> >> try { >> >> collection = fsShape.collection(); >> >> } catch (IOException e) { >> >> >> >> // TODO Auto-generated catch block >> >> >> >> e.printStackTrace(); >> >> } >> >> >> >> FeatureIterator iterator = collection.features(); >> >> >> >> while (iterator.hasNext()){ >> >> Feature f = iterator.next(); >> >> >> >> lgg.add(f); >> >> } >> >> >> >> >> >> Where fsShape is a working instance of FeatureResults with about a >> hundred roads in it. >> >> >> >> I'm not sure if one of the elements is a problem adding to the graph or >> if the whole structure is bogus, which leads to second question: >> >> >> >> I downloaded the 2.2RC3src in an attempt to troubleshoot, unzipped it, >> mvn install'd it, got a good build, and it doesn't appear to contain the >> source code...? Just the full set of .jar files with no source >> attached? >> >> >> >> I'm a maven novice, so maybe I'm gooning something up there. Any help >> or anyone with experience in the graph module who could lend some >> tips/source code would be appreciated. >> >> >> >> Thanks, >> >> >> >> Jeff >> >> >> >> >> >> (sorry if this shows up as a dupe. I mistakenly sent from another >> account last night...) >> >> >> >> >> ----------------------------------------------------------------------- >> -- >> Take Surveys. Earn Cash. Influence the Future of IT >> Join SourceForge.net's Techsay panel and you'll get the chance to share >> your opinions on IT & business topics through brief surveys -- and earn >> cash >> http://www.techsay.com/default.php?page=join.php&p=sourceforge&CID=DEVD >> EV >> >> >> >> !DSPAM:1004,44ca2c56144449771116852! >> _______________________________________________ >> Geotools-gt2-users mailing list >> [email protected] >> https://lists.sourceforge.net/lists/listinfo/geotools-gt2-users >> >> >> >> >> !DSPAM:1004,44ca2c56144449771116852! >> >> >> > > > > > !DSPAM:1004,44ca7192172052207481331! > > ------------------------------------------------------------------------- Take Surveys. Earn Cash. Influence the Future of IT Join SourceForge.net's Techsay panel and you'll get the chance to share your opinions on IT & business topics through brief surveys -- and earn cash http://www.techsay.com/default.php?page=join.php&p=sourceforge&CID=DEVDEV _______________________________________________ Geotools-gt2-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/geotools-gt2-users
