Thanks a lot for your precious help, it worked perfectly. Most probably, the first errors arose from importing a shapefile where I merged some counties using MapViewer - perhaps the newly created shapefile was a bit messy.
However, I now have the problem that I have to repeat the merging of 100 out of the 440 counties using R. But I'll better put the question in a new thread. Katharina -----Original Message----- From: Roger Bivand [mailto:[EMAIL PROTECTED] Sent: Mittwoch, 8. November 2006 18:05 To: Frosch, Katharina Cc: r-sig-geo@stat.math.ethz.ch Subject: Re: readOGR() - choice of layer in MIF/MID file? On Wed, 8 Nov 2006, Frosch, Katharina wrote: > Hello all, > > [this is the continuation of a thread originally posted to r-help] > > As recommended by Roger, I installed the rgdal package and went through > the description of my MIF/MID files. However, I was not able to load the > data using readOGR(), most probably because I did not manage to > correctly specify the layer. As I am pretty new to spatial data analysis > and R, I am still a bit lost. > > I tried with > setwd("E\\Maps\\MIF") > test<-readOGR("testmif.mif", layer = "layer1") > Could you try: test<-readOGR("testmif.mif", layer = "testmif") treating the data source name as the file and the layer as the file name without extensions? Roger > and got the error message "Error in ogrInfo(dsn = dsn, layer = layer: > Cannot open layer" > > testmif.MIF > testmif.MID > containing "points", "polygons" and "regions" and corresponding > attribute data. > (R version 2.4.0 on Windows XP) > > How to find out the correct layer name? The description file of the > MIF/MID file contains only descriptions of the attributes and elements, > but no explicit layer names. > > Katharina > > ****************************+ > > Katharina Frosch > Rostocker Zentrum > Konrad-Zuse-Str. 1 > 18057 Rostock > Tel.: (0381) 2081-148 > Fax: (0381) 2081-448 > Mail: [EMAIL PROTECTED] > > > > > -----Original Message----- > From: Roger Bivand [mailto:[EMAIL PROTECTED] > Sent: Dienstag, 7. November 2006 20:47 > To: Frosch, Katharina > Cc: r-help@stat.math.ethz.ch > Subject: RE: [R] wrong fill colors in polygon-map > > On Tue, 7 Nov 2006, Frosch, Katharina wrote: > > > Dear Roger: Thank you for your help and the hint with the R-sig-geo > list > > (next time I'll post directly to it)! > > > > I went again through all points you mentioned: > > - polygons and rows of data are in the same order > > - the number of polygons and data rows is identical > > - I experimented with different values, and also defined explicit > > breakpoints without using the quantile (no effect) > > - then I added all.inside=TRUE in findIntervall (no effect) > > > > However, adding the forcefill=FALSE option to the plot command led to > a > > strange effect: three districts were left blank. Two of these > districts > > were districts that are situated around another district (district > > A=city itself, district B=the countryside around). The third > problematic > > district is situated close to the Swiss border and next to a big lake. > I > > deleted the three districts, to see what happens. The problem is > partly > > resolved, but new blank districts appear. > > > > Could this be caused by a corrupted shape file rathern than by R? I > > loaded the shape-file with the Program Mapviewer in MIF/MID format, > > unionized some districts, then exported it to an ESRI-shapefile and > used > > it in R. > > It is at least worth trying. May I suggest reading the MIF/MID file > directly into R using the readOGR() function in the rgdal package? If > you > are a Mac OSX user, there is extra help needed installing rgdal, but on > Windows it is available for binary install directly from CRAN (thanks to > Uwe Ligges). The spatial classes used there are more robust, and the > data > and polygons can be kept together. Polygons may also be dissolved using > objects of the SpatialPolygons class. > > Could I suggest that you move any reply to R-sig-geo, given that the > details of spatial data formats are not of general interest? > > Roger > > > > > I don't have any clue to resolve this...so any hint is very welcome! > > Katharina > > > > > > > > ************************** > > Katharina Frosch > > Rostocker Zentrum > > Konrad-Zuse-Str. 1 > > 18057 Rostock > > Tel.: (0381) 2081-148 > > Fax: (0381) 2081-448 > > Mail: [EMAIL PROTECTED] > > > > > > > > > > -----Original Message----- > > From: Roger Bivand [mailto:[EMAIL PROTECTED] > > Sent: Dienstag, 7. November 2006 13:27 > > To: Frosch, Katharina > > Cc: r-help@stat.math.ethz.ch > > Subject: Re: [R] wrong fill colors in polygon-map > > > > On Tue, 7 Nov 2006, Frosch, Katharina wrote: > > > > > Dear all, > > > > > > I would like to produce a map with information about the patenting > > > activity in German districts, by coloring districts with different > > > degrees of patenting activity in different colors. I work with the > > > packages maptools, maps and spdep. The map data is read from an > > external > > > .shp file (+ the corresponding .shx and .dbf files). Plotting a map > > with > > > the IDs or the patenting indicator itself works fine. But coloring > the > > > map leads to completely odd results (wrong colors for most of the > > > regions). I also tried simpler values (just 0 and 1 for different > > > regions), same problem. I tried to check whether there is any > problem > > > with the match of data and district ids, but everything seemed to be > > > fine. > > > > > > Sample code: > > > **************** > > > brks.pat<-quantile(patenting$patbus) > > > #palette.pat<-c("green", "blue", "grey", "darkgrey", "red") > > > palette.pat<-c(rep("green", 4), "red") > > > plot(iab7.poly, col=palette.pat[findInterval(patenting$patbus, > > > brks.pat)]) > > > legend(1200, -200, fill=palette.pat, legend=round(brks.pat,2), > > cex=0.6) > > > title(main="patenting activity in german districts") > > > > > > Data: > > > ****** > > > Iab7.poly contains the polygons of 343 German districts > > > patenting$patbus contains the number of corporate patents per > 100.000 > > > inhabitants for each district > > > > (R-sig-geo may be a more focussed list for this kind of question) > > > > If the polygons in Iab7.poly are in the same order as the rows of > > patenting, and the number of polygons is the same as the number of > rows, > > it is possible that the breakpoints are not quite what you think (if > for > > example some of the quantiles are equal, which happens with > > zero-inflated > > data). Omitting all.inside=TRUE in findInterval() can also lead to the > > insertion of NA values into the vector of colours. > > > > Perhaps have a look at the classInt package for some examples of > > choosing > > class intervals i.a. for map display. > > > > Roger > > > > > > > > Any ideas would be appreciated! > > > > > > Best regards, > > > Katharina > > > > > > > > > > > > ****************************** > > > > > > Katharina Frosch > > > Rostock Center for the Study of Demographic Change > > > Konrad-Zuse-Str. 1 > > > 18057 Rostock > > > Tel.: (0381) 2081-148 > > > Fax: (0381) 2081-448 > > > Mail: [EMAIL PROTECTED] > > > > > > > > > > > > > > > > > > > > > ---------- > > > This mail has been sent through the MPI for Demographic > > Rese...{{dropped}} > > > > > > ______________________________________________ > > > R-help@stat.math.ethz.ch 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. > > > > > > > > > -- 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] ---------- This mail has been sent through the MPI for Demographic Rese...{{dropped}} _______________________________________________ R-sig-Geo mailing list R-sig-Geo@stat.math.ethz.ch https://stat.ethz.ch/mailman/listinfo/r-sig-geo
