Hi All, I'm trying to generate a graph layout where I already have the positions of the nodes, but essentially I want Rgraphviz to figure out how the edges should appear. I guess the first question would be does Rgraphviz support the position attribute? Here is what I have tried so far to see if using the 'pos' attribute even works: # get the graph set.seed(123) V <- letters[1:5] M <- 1:3 g1 <- randomGraph(V, M, .2) # and here is the default z <- agopen(g1, "foo") plot(z) # now try to modify the positions nodeNames <- nodes(g1) nNodes <- length(nodeNames) nodePos <- vector("character", nNodes) names(nodePos) <- nodeNames nodePos[1:nNodes] <- c(".15,.15",".25,.25",".35,.35",".45,.45",".55,.55") # note I have tried the above with "x,y!", and have also tried using tens and hundreds values nodeAttrs <- list(pos=nodePos) # using "dot" as the layout engine, the '!' above is supposed to keep it from changing the node position, see: http://www.graphviz.org/pub/scm/graphviz2/doc/info/attrs.html#a:pos z <- agopen(g1,name="foo",nodeAttrs=nodeAttrs) plot(z) # try using Pin in Neato nodePin <- character(nNodes) names(nodePin) <- nodeNames nodePin[1:nNodes] <- "TRUE" nodeAttrs <- list(pos=nodePos, pin=nodePin) z <- agopen(g1,name="foo",nodeAttrs=nodeAttrs,layoutType="neato") plot(z) I also checked the slot AgNodes to verify if it was just getting changed when calling plot, but the positions are not what I would expect if the nodes were laid out in a straight line. Any suggestions? Is at all what I am trying to do even possible? Thanks in advance. -Robert Robert M. Flight, Ph.D. Bioinformatics and Biomedical Computing Laboratory University of Louisville Louisville, KY PH 502-852-0467 EM robert.flight at louisville.edu EM rflight79 at gmail.com Williams and Holland's Law: ? ? ?? If enough data is collected, anything may be proven by statistical methods.