[R-sig-Geo] Converting Grid to factor list
Edzer J. Pebesma
e.pebesma at geo.uu.nl
Mon Jan 9 08:28:17 CET 2006
Ronnie Babigumira wrote:
>Edzer
>Many thanks. The grid was created in ArcView and exported as an ascii file. I then read it in R using the read.asciigrid
>function in map tools
>
>Any ideas?
>
>
Yes; the function returns an object of class SpatialGridDataFrame:
> example(read.asciigrid)
rd.scg> x <- read.asciigrid(system.file("external/test.ag",
package = "sp")[1])
rd.scg> class(x)
[1] "SpatialGridDataFrame"
attr(,"package")
[1] "sp"
rd.scg> image(x)
> names(x)
[1] "/home/edzer/S/library/sp/external/test.ag"
> names(x) = "foo"
> f = factor(round(x$foo))
> summary(f)
357 394 270 310 398 294 295 303
307 391
18 18 17 17 17 16 16 16
16 16
[etc., etc.,...]
250 256 265 274 290 291 297 299
(Other) NA's
9 9 9 9 9 9 9 9
1938 6097
>
The renaming to foo was not necessary, but quotes would have
been necessary around the name as it contained slashes. I rounded
the values because they were numeric.
--
Edzer
>Ronnie
>
>Edzer J. Pebesma wrote:
>
>
>>Ronnie, you didn't tell us how you created the grid. Is it on of the
>>grid classes in package sp? In that case you can address the
>>variable in it by it's name, say foo:
>>
>>mygrid.f <- factor(mygrid$foo)
>>
>>hth,
>>--
>>Edzer
>>
>>Ronnie Babigumira wrote:
>>
>>
>>
>>>Hi listers
>>>I would like to change a grid to a factor list so as to apply Join
>>>Count statistics however when I use
>>>mygrid.f <- factor(mygrid)
>>>
>>>I get an error message " 'x' must be atomic".
>>>
>>>Looking through the RHelp archives, I have chanced on emails with a
>>>similar problem but no direct answer to this. Is anyone farmiliar with
>>>this and how can I go about it
>>>
>>>
>>>Many thanks
>>>
>>>Ronnie
>>>
>>>_______________________________________________
>>>R-sig-Geo mailing list
>>>R-sig-Geo at stat.math.ethz.ch
>>>https://stat.ethz.ch/mailman/listinfo/r-sig-geo
>>>
>>>
>>>
>>>
>>
>>
>
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