[R-sig-Geo] melt spatialPixelDataFrame

[Michael Sumner]

Right, sure enough I got the x.1 and y.1 as per my first reply with
raster 1.9-92, but after update to 2.0-08 I get your results without
them. And, to be sure, see my run in a fresh session.

I need to explore more to understand this, but things should work as
expected with sp if you don't load raster (for now).

Robert? Sorry I'm not familiar enough with raster to hunt this down
easily, so I thought I'd raise it.

Cheers, Mike.

Code to run:


library(sp)
data(meuse.grid)
m = SpatialPixelsDataFrame(points = meuse.grid[c("x", "y")], data = meuse.grid)
head(as.data.frame(m))



library(raster)
head(as.data.frame(m))



Session:

> library(sp)
> data(meuse.grid)
> m = SpatialPixelsDataFrame(points = meuse.grid[c("x", "y")], data = meuse.grid)

> head(as.data.frame(m))
       x      y part.a part.b      dist soil ffreq    x.1    y.1
1 181180 333740      1      0 0.0000000    1     1 181180 333740
2 181140 333700      1      0 0.0000000    1     1 181140 333700
3 181180 333700      1      0 0.0122243    1     1 181180 333700
4 181220 333700      1      0 0.0434678    1     1 181220 333700
5 181100 333660      1      0 0.0000000    1     1 181100 333660
6 181140 333660      1      0 0.0122243    1     1 181140 333660
>
>
>
> library(raster)
raster 2.0-08 (27-June-2012)
> head(as.data.frame(m))
       x      y part.a part.b      dist soil ffreq
1 181180 333740      1      0 0.0000000    1     1
2 181140 333700      1      0 0.0000000    1     1
3 181180 333700      1      0 0.0122243    1     1
4 181220 333700      1      0 0.0434678    1     1
5 181100 333660      1      0 0.0000000    1     1
6 181140 333660      1      0 0.0122243    1     1
>
> sessionInfo()
R version 2.15.1 Patched (2012-06-29 r59683)
Platform: x86_64-pc-mingw32/x64 (64-bit)

locale:
[1] LC_COLLATE=English_Australia.1252  LC_CTYPE=English_Australia.1252
[3] LC_MONETARY=English_Australia.1252 LC_NUMERIC=C
[5] LC_TIME=English_Australia.1252

attached base packages:
[1] stats     graphics  grDevices utils     datasets  compiler  methods
[8] base

other attached packages:
[1] raster_2.0-08 sp_0.9-99

loaded via a namespace (and not attached):
[1] grid_2.15.1    lattice_0.20-6 tools_2.15.1





On Wed, Jul 18, 2012 at 11:48 PM, Johannes Radinger <JRadinger at gmx.at> wrote:
> Hi,
>
>> > I tried:
>> > 1) to transform the SPDF to a normal dataframe with as.data.frame(spdf)
>> but then I loose my x and y columns. Thus I can't use them in melt. Was
>> that behavior changed recently?
>>
>> No, I really don't think so. Are you sure?  Here x.1 and y.1 are the
>> (re-attached) grid point coordinates, which incidentally are copies of
>> the original data "x" and "y".
>>
>> data(meuse.grid)
>> m = SpatialPixelsDataFrame(points = meuse.grid[c("x", "y")], data =
>> meuse.grid)
>> head(as.data.frame(m))
>>        x      y part.a part.b      dist soil ffreq    x.1    y.1
>> 1 181180 333740      1      0 0.0000000    1     1 181180 333740
>> 2 181140 333700      1      0 0.0000000    1     1 181140 333700
>> 3 181180 333700      1      0 0.0122243    1     1 181180 333700
>
> I am not 100% sure but my output looks different from yours (I am missing x.1 and y.1, the original coords from the SPDF and not the re-attached ones)
> Here the output with the same example and sessionInfo():
>
>> library(raster)
> Loading required package: sp
> raster 2.0-08 (27-June-2012)
>> data(meuse.grid)
>> m = SpatialPixelsDataFrame(points = meuse.grid[c("x", "y")], data = meuse.grid)
>> head(as.data.frame(m))
>        x      y part.a part.b      dist soil ffreq
> 1 181180 333740      1      0 0.0000000    1     1
> 2 181140 333700      1      0 0.0000000    1     1
> 3 181180 333700      1      0 0.0122243    1     1
> 4 181220 333700      1      0 0.0434678    1     1
> 5 181100 333660      1      0 0.0000000    1     1
> 6 181140 333660      1      0 0.0122243    1     1
>> sessionInfo()
> R version 2.14.1 (2011-12-22)
> Platform: i686-pc-linux-gnu (32-bit)
>
> locale:
>  [1] LC_CTYPE=en_US.UTF-8       LC_NUMERIC=C
>  [3] LC_TIME=en_US.UTF-8        LC_COLLATE=en_US.UTF-8
>  [5] LC_MONETARY=en_US.UTF-8    LC_MESSAGES=en_US.UTF-8
>  [7] LC_PAPER=C                 LC_NAME=C
>  [9] LC_ADDRESS=C               LC_TELEPHONE=C
> [11] LC_MEASUREMENT=en_US.UTF-8 LC_IDENTIFICATION=C
>
> attached base packages:
> [1] stats     graphics  grDevices utils     datasets  methods
> [7] base
>
> other attached packages:
> [1] raster_2.0-08 sp_0.9-99
>
> loaded via a namespace (and not attached):
> [1] grid_2.14.1    lattice_0.20-0 tools_2.14.1
>
>
>
>
> Any idea?
>
> /johannes



-- 
Michael Sumner
Hobart, Australia
e-mail: mdsumner at gmail.com