I'm hoping that folks out there with expertise in working with the party package can help me out here. My team is trying to convert party tree output into a text file format that can be read by our image processing software. We are running into difficulties because the way the two different programs identify their nodes is different. R numbers it's nodes 1, 2, 3, 4, 5, 6 etc. down the "yes" answers in the tree until a terminal node is reached, at which point it backs up to the parent of that terminal node, gives its "no" child the next number available, follows any additional yes children down from there until it hits a terminal node, and repeats necessary. Our image processing system uses a coordinate system that labels each node according to its location in the tree (e.g. row 4, column 43). For instance, the first split in the tree is at location (1,1), the two daughter nodes are (2,1) and (2,2), and their daughters are (3,1), (3,2), (3,3), (3,4), etc. etc. on down the tree. It assigns these location coordinates referencing all possible node locations. In other words, if node (2,1) in the above scenario happened to be a terminal node, the daughters of node 2,2 would still be labeled (3,3) and (3,4), even though nodes (3,1) and (3,2) would not actually exist. They are still, from a labeling/ID perspective, retained, as it were, as phantom place holders. Given that the plot function in the party package is able to produce output that shows these column and row relationships in graphical format, it seems to me that there ought to be a way to extract this positional information from the package, but I haven't found a way to do it yet. The plot.tree info in the manual says it creates "an (invisible) list with components x and y giving the coordinates of the tree nodes," and I'm wondering if it's talking about "tree coordinates," as used by our image processor, or if it's refering to the x and y position on the printed plot. Either way, I don't know how to access those x/y numbers. At any rate, I'm pretty stumped. It seems to me that since the positional relationships are produced in the plots, there ought to be a way to get at them, programmatically. Any suggestions out there? -- View this message in context: http://r.789695.n4.nabble.com/party-tree-coordinates-tp4648047.html Sent from the R help mailing list archive at Nabble.com.
party tree coordinates
2 messages · aelmore, Achim Zeileis
On Wed, 31 Oct 2012, aelmore wrote:
I'm hoping that folks out there with expertise in working with the party package can help me out here. My team is trying to convert party tree output into a text file format that can be read by our image processing software. We are running into difficulties because the way the two different programs identify their nodes is different. R numbers it's nodes 1, 2, 3, 4, 5, 6 etc. down the "yes" answers in the tree until a terminal node is reached, at which point it backs up to the parent of that terminal node, gives its "no" child the next number available, follows any additional yes children down from there until it hits a terminal node, and repeats necessary.
And that's essentially also how the visualization works. A suitably sized grid is set up first and then grid viewports are recursively created and traversed.
Our image processing system uses a coordinate system that labels each node according to its location in the tree (e.g. row 4, column 43). For instance, the first split in the tree is at location (1,1), the two daughter nodes are (2,1) and (2,2), and their daughters are (3,1), (3,2), (3,3), (3,4), etc. etc. on down the tree. It assigns these location coordinates referencing all possible node locations. In other words, if node (2,1) in the above scenario happened to be a terminal node, the daughters of node 2,2 would still be labeled (3,3) and (3,4), even though nodes (3,1) and (3,2) would not actually exist. They are still, from a labeling/ID perspective, retained, as it were, as phantom place holders. Given that the plot function in the party package is able to produce output that shows these column and row relationships in graphical format, it seems to me that there ought to be a way to extract this positional information from the package, but I haven't found a way to do it yet.
I think we haven't got anything in the package that delivers this out of the box. (Also note that the tree is often sparser than all binary splits that could occur.)
The plot.tree info in the manual says it creates "an (invisible) list with components x and y giving the coordinates of the tree nodes," and I'm wondering if it's talking about "tree coordinates," as used by our image processor, or if it's refering to the x and y position on the printed plot. Either way, I don't know how to access those x/y numbers.
That's not from the "party" package anyways. plot.tree is from the "tree" package whose code bases are not related.
At any rate, I'm pretty stumped. It seems to me that since the positional relationships are produced in the plots, there ought to be a way to get at them, programmatically. Any suggestions out there?
I would suggest that you take a loot at the "partykit" package. It contains a reimplementation of ctree() based on acleaner design of the recursive tree structure. It also offers more functions for user interaction. It comes with a vignette that is still somewhat rough but should give you a good idea how things work. hth, Z