Dear Roger,
  There maybe a new bug in the new elide() funcftion for maptools' version
0.7-2, which was correct in the former version. See below.
#Example in the help page
data(meuse)
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")

##maptools' version 0.7-2, the transformed dataset dropped two variables in
the rightmost: landuse and dist.m.
meuse1 <- elide(meuse, bb=bbox(rivers), scale=TRUE)
> meuse[1,]
       coordinates cadmium copper lead zinc  elev       dist   om ffreq soil
lime landuse dist.m
1 (181072, 333611)    11.7     85  299 1022 7.909 0.00135803 13.6     1
1    1      Ah     50
> meuse1[1,]
          coordinates      x      y cadmium copper lead zinc  elev
dist   om ffreq soil lime
1 (0.23093, 0.660129) 181072 333611    11.7     85  299 1022 7.909
0.00135803 13.6     1    1    1

##maptools' version 0.6-19 + original elide() function: i can't found the
former version for maptools package with elide() function, but i use the
elide() function that you sent me for the 1st time to show its results. You
can try the former version.
meuse1 <- elide(meuse, bb=bbox(rivers), scale=TRUE)
> meuse[1,]
       coordinates cadmium copper lead zinc  elev       dist   om ffreq soil
lime landuse dist.m
1 (181072, 333611)    11.7     85  299 1022 7.909 0.00135803 13.6     1
1    1      Ah     50
> meuse1[1,]  #it didn't drop any variables
          coordinates cadmium copper lead zinc  elev       dist   om ffreq
soil lime landuse dist.m
1 (0.23093, 0.660129)    11.7     85  299 1022 7.909 0.00135803 13.6
1    1    1      Ah     50

 The reason maybe the latest version remains the original x/y coordinates
that resulted in overlaying the rightmost two variables, while the former
version dropped the original x/y coordinates . So i think two additional
colunms maybe needed there.
  Thanks.



-- 
With Kind Regards,

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Zhi Jie,Zhang ,PHD
Tel:+86-21-54237149
Dept. of Epidemiology,School of Public Health,Fudan University
Address:No. 138 Yi Xue Yuan Road,Shanghai,China
Postcode:200032
Email:epistat@gmail.com
Website: www.statABC.com
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