On Fri, 24 Nov 2006, Lorenzo Isella wrote: > Dear All, > I would like to automate the analysis and plotting of data taken from a grid. > Typically I deal with 2 spatial coordinates and a scalar f(x,y), but > the spatial grid is not evenly spaced at all and usually given in this > form: > x y f(x,y) > 0.0 0.048979383 2.7659438106975056 > 0.0 0.044986665 2.603891585041688 > 0.0023807306 0.04787451 2.715949356768243 > 0.0 0.040993948 2.469223979694342 > 0.0023807306 0.043881793 2.5625191444824265 > 0.004761461 0.046769638 2.6629703119429022 > 0.0 0.03700123 2.361940994655468 > 0.0023807306 0.039889075 2.436480700580665 > 0.004761461 0.04277692 2.517958884562618 > 0.0071421918 0.045664765 2.606844303834078 > 0.0 0.060880877 3.470808435449538 > 0.0 0.05691371 3.1907723461238686 > 0.0020467786 0.059650626 3.3672237912200016 > 0.0 0.05294655 2.9558174712065237 > 0.0020467786 0.055683464 3.1075221272152054 > 0.004093557 0.05842038 3.268965886866726 > 0.0020467786 0.051716298 2.8929170062920653 > 0.004093557 0.054453213 3.029154848759894 > 0.006140336 0.057190128 3.1754081073235088 > 0.0 0.02473231 2.138648866573983 > 0.0 0.020556964 2.092324627395541 > > I tried the image plot and lattice but unsuccessfully. Now I am > reading about the sp package ( > http://cran.r-project.org/src/contrib/Descriptions/sp.html ), but I > mainly would like a piece of advice about what tools to use and how to > read and plot these data (I suppose it must be common e.g. in > geography to deal with this kind of problems).
Your data are not on a 2D grid, there are (here) 7 unique x values, but 21 unique y values of 21. You can treat the data as a SpatialPointsDataFrame (see note in R News in 2005), but if you want to display them on an actual grid, you will have to interpolate. For more ideas, perhaps try the R-sig-geo mailing list. > Kind Regards > > Lorenzo > > ______________________________________________ > R-help@stat.math.ethz.ch 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. > -- Roger Bivand Economic Geography Section, Department of Economics, Norwegian School of Economics and Business Administration, Helleveien 30, N-5045 Bergen, Norway. voice: +47 55 95 93 55; fax +47 55 95 95 43 e-mail: [EMAIL PROTECTED] ______________________________________________ R-help@stat.math.ethz.ch 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.
