[R-sig-Geo] adding a scale

Tue May 5 20:22:20 CEST 2015

There is also a 'scalebar' function in the raster package (I have not
compared the two)

Robert

On Mon, Apr 27, 2015 at 7:59 AM, Gilles Benjamin Leduc <gbl1 at hi.is> wrote:
>
>  Not to bad hint :p
>
> So From this one, I modified the function to get it work correctly:
>
> #############################################################################################################################################################################
> ####                                                                                     Scale                                                                                               ####
> #############################################################################################################################################################################
>
> scalebar <- function(loc,length,unit="km" ,degrees = TRUE,cex=par("cex"), ...) {
>         if(missing(loc)) stop("loc is missing")
>         if(missing(length)) stop("length is missing")
>         z <- c(0,length/c(4,2,4/3,1),length*1.1)+loc[1]
>         if(degrees == TRUE) length<-180*(acos((cos(length/6371)-sin(loc[2]*pi/180)*sin(loc[2]*pi/180))/(cos(loc[2]*pi/180)*cos(loc[2]*pi/180))))/pi
>         x <- c(0,length/c(4,2,4/3,1),length*1.1)+loc[1]
>         y <- c(0,length/(10*3:1))+loc[2]
>         cols <- rep(c("black","white"),2)
>         for (i in 1:4) rect(x[i],y[1],x[i+1],y[2],col=cols[i])
>          for (i in 1:5) segments(x[i],y[2],x[i],y[3])
>          labels <- z[c(1,3)]-loc[1]
> labels <- append(labels,paste(z[5]-loc[1],unit))
> text(x[c(1,3,5)],y[4],labels=labels,cex,pos=3,offset=0) }
>
>
> and pushed it in my package https://github.com/giby/Linarius if someone wanna try. I could do some improve to support other units, I'll do that latter on.
>
> Thanks a lot for help
>
> Benjamin
>
> On Saturday, April 25, 2015 10:36 GMT, Guido Schulz <gosz at gmx.de> wrote:
>
>> You may want to check out this paper "Auxiliary Cartographic Functions
>> in R: North Arrow, Scale Bar, and Label with a Leader Arrow"
>> (http://www.jstatsoft.org/v19/c01/paper).
>>
>> It provides functions to add arrow and scale bar for plot.
>>
>>
>> Am 24.04.2015 um 14:10 schrieb Gilles Benjamin Leduc:
>> > Hi again, > > So, I use the plot() function. > I read a shapefile, that I convert in GPS coordinates like this: > > readOGR(dsn=S50V_STRANDLINA_24122014_ISN2004/IS50V_STRANDLINA_SHP", layer="is50v_strandlina_flakar_24122014")->IslHD
>> > spTransform(IslHD,CRS(" +proj=nglat +datum=WGS84 +no_defs +ellps=WGS84 +towgs84=0,0,0 "))->IslHD > > then plot : plot(IslHD) > > I tried several stuff for making a scale, results were either ugly or wrong… > The function Scalebar make a cute scale but really absurd… > > Any idea? > > Best regards
>> > > Benjamin   >  >  > On Thursday, April 23, 2015 05:18 GMT, Frede Aakmann Tøgersen <frtog at vestas.com> wrote: >  >> Hi Benjamin
>> >>
>> >> Yes, there are several ways to do that. But it depends on which kind of plotting function you used. Usually it is a setting of an argument of the plotting function.
>> >>
>> >> I cannot help you more since I don't more than the information you provided in your email.
>> >>
>> >> If you want more help from this list please provide a small example showing which functions you used with information on which package(s) they belong. Then you'll probably get more help.
>> >>
>> >> The small example you can probably find in the example section on the help page for the plotting function.
>> >>
>> >> Best Regards
>> >>
>> >> Frede Aakmann Tøgersen
>> >> Specialist, M.Sc., Ph.D.
>> >> Plant Performance & Modeling
>> >>
>> >> Technology & Service Solutions
>> >> T +45 9730 5135
>> >> M +45 2547 6050
>> >> frtog at vestas.com
>> >> http://www.vestas.com
>> >>
>> >> Company reg. name: Vestas Wind Systems A/S
>> >> This e-mail is subject to our e-mail disclaimer statement.
>> >> Please refer to www.vestas.com/legal/notice
>> >> If you have received this e-mail in error please contact the sender.
>> > >>
>> >> -----Original Message-----
>> >> From: R-sig-Geo [mailto:r-sig-geo-bounces at r-project.org] On Behalf Of Gilles Benjamin Leduc
>> >> Sent: 23. april 2015 02:46
>> >> To: r-sig-geo at r-project.org
>> >> Subject: [R-sig-Geo] adding a scale
>> >>
>> >> Hi all,
>> >>
>> >> I am ploting map from shapefiles (curently read with readOGR from rgdal). >> My PhD supervisor asked me to add a scale… Before going in crazy computation and the arrow function I wonder… Is there a function that can do it automatically (or easily) >>
>> >> Thanks in advance >>
>> >> Benjamin
>> >>
>> >> _______________________________________________
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>> > >
>>
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