thanks for the prompt reply
the method spTransform() worked
I now have an attribute file of class SpatiaPointsDataFrame with EM38
readings. I also have a separate shape file of class
SpatialPolygonsDataFrame which I imported form an ESRI shape file using the
readOGR() method of rgdal. I would like to superpose the two files in a
plot but so far have not been successful in lining them up satisfactorily.
I am not sure if the misalignement is due to my misguided plotting method
p1 <- spplot(x, c("var")) #attribute data
p2 <- spplot (x2) # shapefile
print(p1, split = c(1,1,1,1), more = TRUE)
print(p2, split = c(1,1,1,1), more = FALSE)
or due to the fact that the projections of the two files differ. I am not
sure how to extract projection information from the shape file.
any hints would be appreciated
Karl
|---------+----------------------------------->
| | Roger.Bivand at nhh.no |
| | Sent by: |
| | r-sig-geo-bounces at stat.m|
| | ath.ethz.ch |
| | |
| | |
| | 25/05/2006 15:41 |
| | Please respond to |
| | Roger.Bivand |
| | |
|---------+----------------------------------->
>------------------------------------------------------------------------------------------------------------------------------|
| |
| To: mdsumner at utas.edu.au |
| cc: r-sig-geo at stat.math.ethz.ch |
| Subject: Re: [R-sig-Geo] problems loading spproj library for transform() |
>------------------------------------------------------------------------------------------------------------------------------|
On Thu, 25 May 2006, Michael Sumner wrote:
Hello I have the same problem, I've been meaning to explore further before posting, but since spproj is not on CRAN I don't think I've missed something obvious. This seems to be related to rgdal 0.4-4:
In rgdal, try running example("spTransform-methods") - if it works, use
spTransform() instead of transform().
Sorry for the muddle.
Roger
## using data from ?project example
library(rgdal)
## project works OK
data(state)
res <- project(cbind(state.center$x, state.center$y), "+proj=lcc
+lat_1=48 +lat_2=33 +lon_0=-100")
res1 <- project(res, "+proj=lcc +lat_1=48 +lat_2=33 +lon_0=-100",
inv=TRUE)
## but transform does not
res <- SpatialPoints(res, CRS("+proj=lcc +lat_1=48 +lat_2=33 +lon_0
=-100"))
sessionInfo() #Version 2.3.0 (2006-04-24) #i386-pc-mingw32 #attached base packages: #[1] "methods" "stats" "graphics" "grDevices" "utils"
"datasets"
#[7] "base"
#other attached packages:
# rgdal pixmap abind sp
# "0.4-4" "0.4-4" "1.1-0" "0.8-14"
transform(res, CRS("+proj=longlat"))
#Loading required package: spproj
#Error in transform(res, CRS("+proj=longlat")) :
# for using (coordinate) transform on objects deriving from
Spatial, library spproj is required
#In addition: Warning message:
#there is no package called 'spproj' in: library(package, lib.loc =
lib.loc, character.only = TRUE, logical = TRUE,
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-- 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: Roger.Bivand at nhh.no _______________________________________________ R-sig-Geo mailing list R-sig-Geo at stat.math.ethz.ch https://stat.ethz.ch/mailman/listinfo/r-sig-geo