On Wed, Dec 18, 2013 at 2:52 PM, Simon Delay-Fortier <simon.delay-fort...@mail.mcgill.ca> wrote: > Hi everyone, > > I am a very new user of r (doing most of my previous stuff in vba). I am now > mandated to draw a 3-d surface of a mine pit hole. I have all the location > points (around 5000 points) of the pit in a CSV file under 3 column X, Y & Z. > However, going from page to page on the web, I could not figure out how to > code the figure. Something I noted is that most of the time X and Y have to > be in ascending order but the data I have are not (since they are finite > points of the pit, if X gets in ascending order, Y and Z are not). Also with > the data, sometimes 2 rows fallowing each ohter have the same X and Y value > with a different Z. That would be nice if things could be modeled with rgl > function in order to have a rotating pit, but I would be glad to only have a > 3d surface to start!
How "3d" is your surface here? Because there's "3d" and there's what's known as "2.5d" A 3d surface could be something like the surface of a sphere, or a cave, or an overhanging cliff, whereas a 2.5d surface is a single-valued function of x and y. If you have a true 3d surface then that's beyond me and involves working out surface normals and all sorts of other clever stuff which I don't know about. If its really 2.5d then yes, you do need to compute the values of your surface on a grid in order to display it using rgl's surface3d function. You can do this with some 2d interpolation code, such as kriging or inverse distance weighting, using assorted packages such as automap (which makes it easy but beware) or gstat. Since this seems to be a real-world geography problem, you might haul over to the r-sig-geo mailing list and as there where the spatial guys hang out. Barry ______________________________________________ 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.
