Dear all,
I have a code written under R version 2.10.1 and sp package 0.9-65
that gives different results when it is run in a colleague's computer
with a newer version of R and sp (R version 2.13.1 and sp version
0.9-83). The code is simply the selection of a subset of a
SpatialPixelsDataFrame object.
In my computer, the code behaves as I would expect:
> summary(ModelData)
Object of class SpatialPixelsDataFrame
Coordinates:
min max
x -180 180
y -90 90
Is projected: FALSE
proj4string : [+proj=longlat +ellps=WGS84]
Number of points: 64800
Grid attributes:
cellcentre.offset cellsize cells.dim
x -179.5 1 360
y -89.5 1 180
Data attributes:
Temp_mean Arag
Min. : -1.884 Min. : 1.259
1st Qu.: 1.703 1st Qu.: 1.816
Median : 16.251 Median : 2.814
Mean : 14.017 Mean : 2.756
3rd Qu.: 24.365 3rd Qu.: 3.599
Max. : 31.396 Max. : 4.504
NA's :23457.000 NA's :23734.000
# Selecting a subset:
lat_ok <- intersect(which(coordinates(ModelData)[, 2] <=
60),which(coordinates(ModelData)[, 2] >= -60))
ModelData_new <- ModelData[lat_ok,]
> summary(ModelData_new)
Object of class SpatialPixelsDataFrame
Coordinates:
min max
x -180 180
y -60 60
Is projected: FALSE
proj4string : [+proj=longlat +ellps=WGS84]
Number of points: 43200
Grid attributes:
cellcentre.offset cellsize cells.dim
x -179.5 1 360
y -59.5 1 120
Data attributes:
Temp_mean Arag
Min. : -0.4695 Min. : 1.380
1st Qu.: 12.6654 1st Qu.: 2.539
Median : 21.0919 Median : 3.220
Mean : 18.8588 Mean : 3.107
3rd Qu.: 25.4367 3rd Qu.: 3.746
Max. : 31.3959 Max. : 4.504
NA's :11964.0000 NA's :11968.000
In my friend's computer, although the bounding box of subsetted object
changes, the "Grid attributes" dont:
> summary(ModelData)
Object of class SpatialPixelsDataFrame
Coordinates:
min max
x -180 180
y -90 90
Is projected: FALSE
proj4string : [+proj=longlat +ellps=WGS84]
Number of points: 64800
Grid attributes:
cellcentre.offset cellsize cells.dim
x -179.5 1 360
y -89.5 1 180
Data attributes:
Temp_mean Arag
Min. : -1.884 Min. : 1.259
1st Qu.: 1.703 1st Qu.: 1.816
Median : 16.251 Median : 2.814
Mean : 14.017 Mean : 2.756
3rd Qu.: 24.365 3rd Qu.: 3.599
Max. : 31.396 Max. : 4.504
NA's :23457.000 NA's :23734.000
> # Selecting a subset:
> lat_ok <- intersect(which(coordinates(ModelData)[, 2] <=
60),which(coordinates(ModelData)[, 2] >= -60))
> ModelData_new <- ModelData[lat_ok,]
> summary(ModelData_new)
Object of class SpatialPixelsDataFrame
Coordinates:
min max
x -180 180
y -60 60
Is projected: FALSE
proj4string : [+proj=longlat +ellps=WGS84]
Number of points: 43200
Grid attributes:
cellcentre.offset cellsize cells.dim
x -179.5 1 360
y -89.5 1 180
Data attributes:
Temp_mean Arag
Min. : -0.4695 Min. : 1.380
1st Qu.: 12.6654 1st Qu.: 2.539
Median : 21.0919 Median : 3.220
Mean : 18.8588 Mean : 3.107
3rd Qu.: 25.4367 3rd Qu.: 3.746
Max. : 31.3959 Max. : 4.504
NA's :11964.0000 NA's :11968.000
Is this a bug? This creates problems later in the code when we try to
convert the object into SpatialGrid class and get different bounding
boxes...
Thanks for your help,
Elena
Details of the versions of R and installed packages we are using:
1) In my computer:
> sessionInfo()
R version 2.10.1 (2009-12-14)
x86_64-apple-darwin9.8.0
locale:
[1] en_GB.UTF-8/en_GB.UTF-8/C/C/
en_GB.UTF-8/en_GB.UTF-8
attached base packages:
[1] stats graphics grDevices utils datasets methods base
other attached packages:
[1] rgdal_0.6-24 sp_0.9-65
loaded via a namespace (and not attached):
[1] grid_2.10.1 lattice_0.18-3
2) For my friend's computer:
> sessionInfo()
R version 2.13.1 (2011-07-08)
Platform: i386-apple-darwin9.8.0/i386 (32-bit)
locale:
[1] en_GB.UTF-8/en_GB.UTF-8/C/C/en_GB.UTF-8/en_GB.UTF-8
attached base packages:
[1] stats graphics grDevices utils datasets methods base
other attached packages:
[1] rgdal_0.6-33 sp_0.9-83
loaded via a namespace (and not attached):
[1] grid_2.13.1 lattice_0.19-30
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