[R-sig-Geo] Am i misusing the shift() option in elide(maptools) function?

[Roger Bivand]

On Mon, 10 Dec 2007, zhijie zhang wrote:

> Let me know if the new version of maptools was available. I was waiting to
> use it.

The 0.7-2 source is on CRAN and will move to mirrors when they update. 
Neither Windows nor OSX binaries have updated on CRAN yet, but should do 
so during 10 December (CET and EST I think).

A word of thanks to Kurt Hornik at CRAN, who with helpers not only 
publishes all the 1000+ packages on CRAN, but also checks them first 
across a range of platforms. The speed of response of the CRAN team is one 
of the reasons for making it easy for package maintainers to deal with 
bugs quickly. Thanks also to Uwe Ligges for the Windows binary package 
builds, and to Simon Urbanek for the very complicated OSX binary package 
builds.

Roger

> Thanks.
>
> On Dec 10, 2007 1:34 AM, Roger Bivand <Roger.Bivand at nhh.no> wrote:
>
>>  On Sun, 9 Dec 2007, zhijie zhang wrote:
>>
>>> Dear friends,
>>>  I used the shift() option in elide(maptools) function to shift the x/y
>>> coordiates, but it seemed that it didn't change the coordinates.
>>> #Programs used by me
>>> library(sp)
>>> library(foreign)
>>> library(maptools)
>>>
>>> data(meuse)  #in the help page
>>> coordinates(meuse) <- c("x", "y")
>>> proj4string(meuse) <- CRS("+init=epsg:28992")
>>> data(meuse.riv)
>>> river_polygon <- Polygons(list(Polygon(meuse.riv)), ID="meuse")
>>> rivers <- SpatialPolygons(list(river_polygon))
>>> proj4string(rivers) <- CRS("+init=epsg:28992")
>>>
>>> #rivers
>>> Slot "coords":
>>> [176,] 182003.7  337678.6
>>> Slot "bbox":
>>>        min      max
>>> r1 178304.0 182331.5
>>> r2 325698.5 337684.8
>>>
>>>
>>> rivers1 <- elide(rivers, shift=c(10000,-10000))  #,shift southeast to
>> 10000,
>>> but it seems unchanged
>>> #rivers1
>>> #the coordinates were the same as that of rivers
>>> Slot "coords":
>>> [176,] 182003.7  337678.6
>>> Slot "bbox":
>>>        min      max
>>> r1 178304.0 182331.5
>>> r2 325698.5 337684.8
>>>
>>> Q: Am i misusing the shift() option in elide(maptools) function? Where
>> goes
>>> wrong?
>>
>> Thanks for a very clear report, this was a bug. The shift= argument worked
>> for points but not for lines or polygons. The next release of maptools
>> will correct this, and add rotation options kindly contributed by Don
>> MacQueen.
>>
>> Roger
>>
>>> Thanks.
>>>
>>
>> --
>> 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
>>
>
>
>
>

-- 
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