Hi Roger, Many thanks for Rgshhs. I am very glad to have this additional source of coastlines.
A few comments. I am impressed with axis label handling when using the "plot" command on the spatial polygons imported by Rghhs. I like the suffix given to each number, e.g. "300°E". How do you do this? Setting some kind of "unit" attribute to the longitudes and latitudes? I don't know how to do this, otherwise I'd implement it in the maps I produce with PBSmapping. Second surprise: I reimported the same area but using the option "shift=TRUE" to get longitudes West. I'm used to these numbers being negative, and indeed they still are here as I must select negative longitudes to define xlim. But when issuing the plot command, they are labelled properly, i.e. -70 becomes "70°W". In PBSmapping I must turn automatic xaxis labelling off and relabel myself. I may switch to your classes and methods yet! However in my first test, I got the lakes to be coloured "azure2" but not the ocean, which was white: NWA.i <- Rgshhs("gshhs_i.b", shift=TRUE, xlim = c(280,340), ylim = c (35,75), verbose = TRUE) plot(NWA.i$SP, xlim=c(-70, -55), ylim=c(45, 51), col="khaki", pbg="lightblue", axes=T) So I read the html doc on sp and discovered pbg was the color of "holes", which lakes are but not the ocean, which is just the absence of polygons. So I added a bg color to the above plot command, which should have taken care of that, but it did not. Do you know why? Another question: the help on Rgshhs says we can import only land, for instance, instead of the 4 hierarchic types in gshhs files, by adding "level=1". But if I import everything, can I decide later to make a plot with land only? Or to create a layer with only lakes (no coastline)? I consulted the help for sp as well as the documentation for sp but could not figure out how to do this. When I print the list created by Rgshhs or even just the SP part of it, I see that SP is made of "slots", one of which contains the level. This information is also available in the spatialdata part. But I don't know how to select just the polygons with "level==2". Cheers, Denis Le 05-10-22 à 06:00, [EMAIL PROTECTED] a écrit : > Send R-sig-Geo mailing list submissions to > r-sig-geo@stat.math.ethz.ch > > To subscribe or unsubscribe via the World Wide Web, visit > https://stat.ethz.ch/mailman/listinfo/r-sig-geo > or, via email, send a message with subject or body 'help' to > [EMAIL PROTECTED] > > You can reach the person managing the list at > [EMAIL PROTECTED] > > When replying, please edit your Subject line so it is more specific > than "Re: Contents of R-sig-Geo digest..." > > > Today's Topics: > > 1. New sp add-on packages on sourceforge repository (Roger Bivand) > > > ---------------------------------------------------------------------- > > Message: 1 > Date: Fri, 21 Oct 2005 15:10:43 +0200 (CEST) > From: Roger Bivand <[EMAIL PROTECTED]> > Subject: [R-sig-Geo] New sp add-on packages on sourceforge repository > To: r-sig-geo@stat.math.ethz.ch > Message-ID: <[EMAIL PROTECTED]> > Content-Type: TEXT/PLAIN; charset=US-ASCII > > I have released two new sp add-on packages on the r-spatial > repository. > > Rgshhs converts GSHHS shorelines (as closed polygons) to sp class > SpatialPolygons, which can then be written out as shapefiles for the > chosen region. It's now very slow for full resolution, because > clipping > the largest land polygons takes a lot of time, but hopefully people > don't > do that every time they need data. It is provided with the coarse > dataset, > but works with the full and the others. It leaves the longitude > coordinates in the -20 to 360 range like the data source. Details > of the > Global Self-consistent, Hierarchical, High-resolution Shoreline > Database > are avialable from: > > http://www.soest.hawaii.edu/wessel/gshhs/gshhs.html > > where the low, intermediate, high, and full resolution data may be > downloaded from. I'd be grateful for ideas for making it faster, > and am > looking at providing indices of which level polygons are included in > next-level polygons preprocessed in the package rather than > computing them > each time for chosen polygons. > > A second package is spspatstat, providing interfaces between some sp > classes and the well-supported point pattern analysis package > spatstat. > The spatstat ppp and owin classes are matched with sp equivalents. > > To get a feel for where sp is going, (and after installing sp and > spatstat from CRAN with their dependencies, and the new packages from > http://r-spatial.sourceforge.net/R), try: > > library(Rgshhs) > library(spspatstat) > gshhs.c.b <- system.file("share/gshhs_c.b", package = "Rgshhs") > NZx <- c(160, 180) > NZy <- c(-50, -30) > NZ <- Rgshhs(gshhs.c.b, xlim = NZx, ylim = NZy) > plot(runifpoint(500, as(NZ$SP, "owin"))) > > Hoping for feedback, > > Roger > > -- > 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 > > > End of R-sig-Geo Digest, Vol 26, Issue 12 > ***************************************** > _______________________________________________ R-sig-Geo mailing list R-sig-Geo@stat.math.ethz.ch https://stat.ethz.ch/mailman/listinfo/r-sig-geo