Scaling the scale bar
Alex, thanks for the reproducible example -- please try:
bb = bbox(States)
Scale <- list("SpatialPolygonsRescale",
layout.scale.bar(),
offset = c(bb[1,1] + 20000, bb[2,1] + 20000),
scale = 100000,
fill = c("white", "black"))
l4 = list("sp.text", c(bb[1,1] + 20000, bb[2,1] + 10000), "0")
l5 = list("sp.text", c(bb[1,1] + 120000, bb[2,1] + 10000), "100 km")
spplot(States, "GEN", sp.layout = list(Scale, l4, l5))
For the next time, send a clean script (without the > and + in it), and
remember that as path separator "\\" only works on some operating
systems, "/" on all (I believe).
On 02/27/2014 12:18 PM, Alexander Sommer wrote:
Dear list members, I have got the feeling, that I missed something substantial about /layout.scale.bar/. For example (not a pretty one, but might clarify my point)
URL <- "http://www.geodatenzentrum.de/auftrag1/archiv/vektor/vg250_ebenen/2012/vg250_2012-01-01.utm32s.shape.ebenen.zip" td <- tempdir() setwd(td) temp <- tempfile(fileext = ".zip") download.file(URL, temp) unzip(temp) dir_temp <- paste(tempdir(),
+ "\\vg250_0101.utm32s.shape.ebenen", + "\\vg250_ebenen", + sep = "")
require(rgdal) States <- readOGR(dsn = dir_temp,
+ layer = "vg250_bld", + encoding = "UTF8")
Scale <- list("SpatialPolygonsRescale",
+ layout.scale.bar(),
+ offset = c(mean(States at bbox[1, ]), mean(States at bbox[2, ])),
+ scale = 0.1 * mean(States at bbox),
+ fill = c("white", "black"))
spplot(States, "GEN", sp.layout = Scale)
draws a map of Germany?s States. Now, I would like to change the scale bar, so that it shows a distance of 100 kilometers. How can I assure that the length of the scale bar on the map corresponds with 100 kilometers in reality? (It might be too obvious or some other reason I do not get it. It feels already like the dumbest question to myself. So, my apologies in advance.) Cheers, Alex
Edzer Pebesma Institute for Geoinformatics (ifgi), University of M?nster Heisenbergstra?e 2, 48149 M?nster, Germany. Phone: +49 251 83 33081 http://ifgi.uni-muenster.de GPG key ID 0xAC227795 -------------- next part -------------- A non-text attachment was scrubbed... Name: signature.asc Type: application/pgp-signature Size: 490 bytes Desc: OpenPGP digital signature URL: <https://stat.ethz.ch/pipermail/r-sig-geo/attachments/20140227/93c6f064/attachment.bin>