[R] Defining a viewport scale in {Grid}

[baptiste auguie]

The default units of polygonGrob are "npc", I think you want "native" instead.

Try the following,

 library(grid)
 d = data.frame(x=rnorm(100, 10), y=rnorm(100, -100))
 v = dataViewport(xData=d$x, yData=d$y)
 grid.points(d$x,d$y, default.units="native", vp=v)

HTH,

b.

On 17 February 2012 02:47, geotheory <geotheory1 at gmail.com> wrote:
> Am just feeling my way into the grid library, and cannot figure out how to
> define the plot limits.  3/5 of the example polygons below plot in the
> default 0-1 range viewport.  But when I try to redefine the viewport the
> polygons plot in the same places.  I also get the same result without
> employing push/pop.  (As you can see from the scale I'm trying to introduce,
> I want to plot map polygons.)  Grateful for an idea where I'm going wrong.
>
> pushViewport(viewport(xscale=c(-180,180),yscale=c(-90,90)))
>
> grid.polygon(x=c(0,5,5,0)/100, y=c(0,0,5,5)/100, draw = T)
> grid.polygon(x=c(100,95,95,100)/100, y=c(100,100,95,95)/100, draw = T)
> grid.polygon(x=c(50,70,70,50)/100, y=c(50,50,70,70)/100, draw = T)
> grid.polygon(x=-c(10,10,40,40)/100, y=c(10,40,40,10)/100, draw = T)
> #NEGATIVE X
> grid.polygon(x=c(50,52,52,50)/100, y=-c(50,50,52,52)/100, draw = T)
> #NEGATIVE Y
>
> popViewport()
>
> Thanks in advance.
>
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