sp 0.9-71, which propagates through CRAN, solves this, as discussed
earlier in
http://r-sig-geo.2731867.n2.nabble.com/spplot-1-filling-background-polygon-without-overwriting-foreground-polygon-2-left-justifying-sp-layot-td5615087.html#a5615087
Best regards,
On 10/08/2010 04:18 PM, Lyndon Estes wrote:
> Greetings,
>
> I have two questions related to spplot:
>
> 1. I am trying to plot one SpatialPolygonsDataFrame over another, and
> fill the background polygon with grey. I can't seem to fill the
> background polygon without having it cover over my supposed foreground
> polygon, even if I specify "first = T" (which fails to draw the
> background polygon):
>
> # Code
>
> # Load shapefiles
> con1 <-
> url("http://sites.google.com/site/ldemisc/spplot-question/demo.mdshp.RData";)
> con2 <-
> url("http://sites.google.com/site/ldemisc/spplot-question/demo.sashp.RData";)
> load(con1); load(con2); close(con1); close(con2)
>
> # Set up plot background shape and additional text for map
>
> # Covers over md.shp
> #sa.lst = list("sp.polygons", sa.shp, fill = "grey", col = "black")
>
> # Covers over md.shp
> #sa.lst = list("sp.polygons", sa.shp, fill = "grey", first = F, col =
> "black")
>
> # sa.shp doesn't plot
> #sa.lst = list("sp.polygons", sa.shp, fill = "grey", first = T, col = "black")
>
> # Background polygon works like this, but without fill
> sa.lst = list("sp.polygons", sa.shp, col = "black")
>
> # Additional text - overall mean yield.
> text1 <- list("sp.text", c(360000, -3210000),
> paste("Overall mean yield =",
> round(mean(md....@data[-c(22,69), 4]), 0), "kg/ha"),
> col ="red", cex = 1)
>
> # Scale bar limits and title
> scmax <- round(max(md....@data[, 4]) / 50, 0) * 50
> scmin <- round(min(md....@data[, 4]) / 50, 0) * 50
> byval <- 25
> titlevec <- "Mean district maize yields (kg/ha) 1981-99: Cultivar PAN6528"
>
> # Spplot
> dev.new()
> spplot(md.shp[-c(22,69),], z = 4,
> sp.layout = list(sa.lst, text1),
> col.regions = topo.colors(500),
> at = seq(scmin, scmax, by = byval),
> main = titlevec)
>
> Any advice on how to correctly set "sa.lst" so that sa.shp fills
> underneath md.shp will be much appreciated. I haven't been able to
> find a ready answer in the help files, except for this:
>
> "The order of items in sp.layout matters; objects are drawn in the
> order they appear. Plot order and prevalence of sp.layout items: for
> points and lines, sp.layout items are drawn before the points (to
> allow for grids and polygons); for grids and polygons sp.layout is
> drawn afterwards (so the item will not be overdrawn by the grid and/or
> polygon). Although a matter of taste, transparency may help when
> combining things. "
>
> But, beyond what I have tried so far, I can't figure out how to write
> the code so that sa.shp is drawn first.
>
> The second question:
>
> 2. Is there an option to pass to:
>
> text1 <- list("sp.text", c(360000, -3210000),
> paste("Overall mean yield =",
> round(mean(md....@data[-c(22,69), 4]), 0), "kg/ha"),
> col ="red", cex = 1)
>
> so that the text is left-justified on the coordinates c(360000,
> -3210000)? At the moment it seems that the text is centered at this
> location.
>
> Thanks in advance for any help you can provide.
>
> Best, Lyndon
>
> _______________________________________________
> R-sig-Geo mailing list
> R-sig-Geo@stat.math.ethz.ch
> https://stat.ethz.ch/mailman/listinfo/r-sig-geo
--
Edzer Pebesma
Institute for Geoinformatics (ifgi), University of Münster
Weseler Straße 253, 48151 Münster, Germany. Phone: +49 251
8333081, Fax: +49 251 8339763 http://ifgi.uni-muenster.de
http://www.52north.org/geostatistics e.pebe...@wwu.de
_______________________________________________
R-sig-Geo mailing list
R-sig-Geo@stat.math.ethz.ch
https://stat.ethz.ch/mailman/listinfo/r-sig-geo
