Hello again, I have found further depths of confusion concerning delaunay triangulations to explore.
Here is the code I'm using to create the confusing results: bm <- getbm(x) # a data.frame with 2 columns and 800 rows, values are integers ranging from 1 to 82 del <- deldir(bm) # creating an object of type deldir with the 800 coordinates from bm tri <- triang.list(del) # creating a list of length n, holding the n triangles created by the delaunay triangulation with deldir(bm) as data.frames geodel <- delaunayn(bm) # creating a matrix with 3 columns and m rows for the m triangles created by the delaunay triangulation using delaunayn(bm) from geometry-package now, the following is what I would expect: n and m should be the same, since both triangulations should give me the same number of triangles, right? but this is what I get: nrow(geodel) = 1584 length(tri) = 1186 This confuses me and I have the feeling I have left out some very important parameter either in delaunayn() or deldir() to create the different results. There is however more confusion to come, this time in the result of triang.list(del): Every element in that list is a data.frame holding information on one triangle. It has 3 columns and 3 rows with column headers 'ptNum', 'x' and 'y'. Now I would expect, that 'ptNum' would give me the index at which I can find the coordinates 'x' and 'y' as a row in my original data.frame of coordinates, bm. And for example bm[1,] gives me the same 'x' and 'y' that are listed in data.frame tri[1] as 'ptNum' = 1. But for some other points this does not work and for example the 'x' and 'y' of 'ptNum' = 129 do not match bm[129, ]. Have I totally misunderstood the meaning of 'ptNum' in this case or does my mistake lie somewhere else? Once again please excuse my slightly chaotic description of my problems and my faulty english and thanks for any help you can give! Raphael On 5/21/14, Rolf Turner <r.tur...@auckland.ac.nz> wrote: > On 21/05/14 23:34, Raphael Päbst wrote: >> I believe you are right. A night of sleep has done wonders for my >> understanding of the problem. > > Oh sleep it is a gentle thing > Beloved from pole to pole! > >> Thank you for your patience and help! > > Patience? Moi? This must be some new use of the word "patience" with > which I am not familiar! :-) > > Glad your tessellations are working out. > > cheers, > > Rolf > > ______________________________________________ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.
