merge(Table1, Table2, by = intersect(c("XCOORD", "YCOORD"), c("XCOORD", "YCOORD")), all = TRUE)
It might not handle the amount of data you have, but, if your tables are normal dataframes, it would do the job with a smaller dataset. It doesn't work with Spatial*DataFrames (yet?). Mikkel --- Roger Bivand <[EMAIL PROTECTED]> wrote: > On Fri, 8 Sep 2006, Michael Sumner wrote: > > > Hello, I can think of a couple of simple-minded > approaches that would > > take some time - either relying on direct > string-matching for the unique > > coordinates, or by some contrived overlay. > > > > However, there's probably far better approaches - > a couple of questions: > > > > Can you predefine the set of all unique > coordinates without reading all > > the tables from file? > > - if so you might simplify the identification of > each individual > > coordinate, for matching the records > > > > Are the coordinates (intended to be) on a regular > grid? (This seems > > unlikely, although it is nearly true given your X > coordinates). > > The key question is what the data are. To me they > look like a global > regular grid with some slippage in the print() - the > underlying diff() of > the unique x's and y's is almost certainly regular. > I'm not sure why they > are in text files either (model output?). But some > bits of the grid may be > missing, the question being whether this is regular. > If as an earlier > response indicated different data sets have > different grid cells > missing, then we need the overall grid to start > with, then grab the row > and column indices (and/or grid index), and attach > these to the data rows. > > If the solution needs to be robust, and have a > longer term utility, I > would go for using MySQL, Terralib, and aRT. The > data representation is > that of the Terralib Cell object, so the question > would be how to upload > to the database from the text files. > > aRT is at: > > http://www.est.ufpr.br/aRT/ > > By the way, 1M by 100 by 8 bytes is pushing 32-bit R > - but handing off a > lot of the data storage to a database relieves this > greatly. > > Roger > > > > > Cheers, Mike. > > > > > > isidora k wrote: > > > Hi everyone! > > > I have 100 tables of the form: > > > XCOORD,YCOORD,OBSERVATION > > > 27.47500,42.52641,177 > > > 27.48788,42.52641,177 > > > 27.50075,42.52641,179 > > > 27.51362,42.52641,178 > > > 27.52650,42.52641,180 > > > 27.53937,42.52641,178 > > > 27.55225,42.52641,181 > > > 27.56512,42.52641,177 > > > 27.57800,42.52641,181 > > > 27.59087,42.52641,181 > > > 27.60375,42.52641,180 > > > 27.61662,42.52641,181 > > > ..., ..., ... > > > with approximately 1000000 observations for > each. All > > > these tables have the same xcoord and ycoord and > I > > > would like to get a table of the form > > > XCOORD,YCOORD,OBSERVATION1,OBSERVATION2,... > > > 27.47500,42.52641,177,233,... > > > 27.48788,42.52641,177,345,... > > > 27.50075,42.52641,179,233,... > > > 27.51362,42.52641,178,123,... > > > 27.52650,42.52641,180,178,... > > > 27.53937,42.52641,178,...,... > > > 27.55225,42.52641,181,... > > > 27.56512,42.52641,177,... > > > 27.57800,42.52641,181,... > > > 27.59087,42.52641,181,... > > > 27.60375,42.52641,180,... > > > 27.61662,42.52641,181,... > > > In other words I would like to merge all the > tables > > > taking into account the common row names of > their > > > xcoords AND ycoords. > > > Not all tables have the same number of > observations > > > which means that not all pairs of x and y coords > > > match. > > > Is there a way to do this in R? > > > I would be grateful for any advice. > > > Many thanks > > > Isidora > > > > > > _______________________________________________ > > > R-sig-Geo mailing list > > > R-sig-Geo@stat.math.ethz.ch > > > https://stat.ethz.ch/mailman/listinfo/r-sig-geo > > > > > > > > > > > > > _______________________________________________ > > R-sig-Geo mailing list > > R-sig-Geo@stat.math.ethz.ch > > https://stat.ethz.ch/mailman/listinfo/r-sig-geo > > > > -- > 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-sig-Geo mailing list > R-sig-Geo@stat.math.ethz.ch > https://stat.ethz.ch/mailman/listinfo/r-sig-geo > _______________________________________________ R-sig-Geo mailing list R-sig-Geo@stat.math.ethz.ch https://stat.ethz.ch/mailman/listinfo/r-sig-geo