Hi, this doesn't have much to do with tripGrid, since the object to plot is just a SpatialGridDataFrame.
I don't use PBSmapping, so I haven't looked at that - perhaps there is an add = TRUE option to plotMap (?), so perhaps you could do this: image(x2009.final) plotMap(..., add = TRUE) Your main issue may be that you are using the Pacific view (0, 360) longitudes rather than (-180,180). I don't know how/if plotMap deals with that, Otherwise, I would use a different data set and just use the sp plot functions. image(x2009.final) library(maptools) data(wrld_simpl) plot(elide(wrld_simpl, shift = c(360, 0)), add = TRUE) You need to "elide" it to shift it 360 in longitude since your range is c(292,303.5) The same will work with other polygon data in longlat read with rgdal::readOGR or maptools::readShapePoly. To actually crop wrld_simpl you can use "[" with matches on the data attributes, or use rgeos::gIntersection. You also could modify your input data to be in the range -180,180, or use a map projection before using the trip* functions. I know there's a lot of options listed above, but it really does depend on which aspects matter to you. HTH On Tue, Mar 11, 2014 at 10:09 AM, Trevor Davies <davies.tre...@gmail.com> wrote: > Hello, > > Sorry for the lack of a complete example but this is more of a class type > question. > > I have a map of the coast that I generated through PBSmapping: > > xlims <- c(292,303.5) > ylims <- c(41.5,49.5) > plotMap(worldLLhigh, xlim=xlims, ylim=ylims, col=grey(0.1),bg=grey(0.9), > xlab="", ylab="", las=1, tck=-0.015, axes=F) > > I want to add an intensity grid from an object that I created through the > excellent 'trip' package (results in an sp class object > (SpatialGridDataFrame)) and this is where I'm having difficulty. I know > maptools allows you to change formats from sp to PBSmapping but I can't > seem to identify how to do it for a SpatialGridDataFrame. > > I get the SpatialGridDataFrame object via: > > x2009.grid <- makeGridTopology(data2009.sp, cells.dim = c(cell.x1, > cell.y1), xlim=xlims, ylim=ylims,buffer = 0, cellsize = NULL,adjust2longlat > = FALSE) > x2009.final <- tripGrid(data2009.sp, grid = x2009.grid, method = > "pixellate") > > For most of these maps I usually just add the grid layer using the image > function but what I currently have worked out is quite messy and I think > prone to error for other applications. > > Of course, I can plot the SpatialGridDataFrame object > via: spplot(x2009.final) which would be great but I can't figure out how to > add my coastline via the PBSmapping plotMap call. > > Could someone please suggest a more direct approach? > Thank you. > > [[alternative HTML version deleted]] > > ______________________________________________ > 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. -- Michael Sumner Hobart, Australia e-mail: mdsum...@gmail.com ______________________________________________ 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.
