[R-sig-Geo] stplot - legend/classes of categorical vairable

[Edzer Pebesma]

Hi Richard, stplot as it is on CRAN does not support factor variables. I
added this support to the dev version on github, e.g. try this
(reproducible!) example:

# install spacetime from github:
devtools::install_github("edzer/spacetime")

library(spacetime)
example(STFDF)
set.seed(42)
gridded(stfdf at sp) = TRUE
stfdf$f = factor(sample(c("a", "b", "c"), 12, replace = TRUE))
library(RColorBrewer)
stplot(stfdf[,,"f"], col.regions = brewer.pal(3, "Accent"))


Make sure that your variable IS a factor, e.g. by

fdf at crop_id = as.factor(fdf at crop_id)

Your data contains many points. If they are laid out on a grid, the plot
improves if you do

gridded(fdf at sp) = TRUE

so that stplot knows, too.

On 03/04/2015 11:45 AM, richard.redweik at posteo.de wrote:
> Hello,
> 
> I have an object of class STFDF named 'fdf'. I want to create a stplot
> in which the categorical variable crop_id resp. crop_short is visualized
> per year.
> 
> Currently I am only able to assign a color/legend entry to a range of
> crop_ids, e.g. green --> [1, 2], yellow --> (2, 3]:
> 
>> col <- brewer.pal(8, "Accent")
>> color <- colorRampPalette(col)(18)
>> stplot(fdf[,, "crop_id"], col.regions=color, cuts=18)
> 
> However, this does mean, that the crop_ids 1 and 2 are assigned to green.
> When changing the cuts parameter to cuts=19, I get an unambigious but
> not very readable assignment, e.g. green --> [1, 1.947], yellow -->
> (1.947, 2.895].
> 
> Now I am wondering, what is the best way to get one class resp. legend
> entry per crop_id, e.g. green --> 1, yellow --> 2 etc.
> 
> Does someone know how to do this?
> 
> Thanks in advance,
> Richard
> 
> PS:
> Summary of my fdf object:
> 
>> summary(fdf)
> Object of class STFDF
>  with Dimensions (s, t, attr): (17511, 11, 6)
> [[Spatial:]]
> Object of class SpatialPoints
> Coordinates:
>       min     max
> x 3464500 3654500
> y 2828500 3026500
> Is projected: NA
> proj4string : [NA]
> Number of points: 17511
> [[Temporal:]]
>      Index                       timeIndex
>  Min.   :1995-01-01 00:00:00   Min.   : 1.0
>  1st Qu.:1997-07-02 12:00:00   1st Qu.: 3.5
>  Median :2000-01-01 00:00:00   Median : 6.0
>  Mean   :2000-01-01 08:43:38   Mean   : 6.0
>  3rd Qu.:2002-07-02 12:00:00   3rd Qu.: 8.5
>  Max.   :2005-01-01 00:00:00   Max.   :11.0
> [[Data attributes:]]
>     objectid          crop_id        crop_short         year           prob
>  Min.   :3222754   Min.   : 1.00   WSWH   :79136   Min.   :1995   Min.   :1
>  1st Qu.:3255362   1st Qu.: 3.00   MAIF   :62594   1st Qu.:1997   1st Qu.:1
>  Median :3287732   Median :10.00   RAPE   :13881   Median :2000   Median :1
>  Mean   :3289614   Mean   :11.56   PULS   :10785   Mean   :2000   Mean   :1
>  3rd Qu.:3322247   3rd Qu.:19.00   WBAR   :10095   3rd Qu.:2003   3rd Qu.:1
>  Max.   :3367519   Max.   :19.00   MAIZ   : 5069   Max.   :2005   Max.   :1
>                                    (Other):11061
>  nuts_code
>  FR25:192621
> 
> _______________________________________________
> R-sig-Geo mailing list
> R-sig-Geo at r-project.org
> https://stat.ethz.ch/mailman/listinfo/r-sig-geo

-- 
Edzer Pebesma
Institute for Geoinformatics (ifgi),  University of Münster,
Heisenbergstraße 2, 48149 Münster, Germany; +49 251 83 33081
Journal of Statistical Software:   http://www.jstatsoft.org/
Computers & Geosciences:   http://elsevier.com/locate/cageo/
Spatial Statistics Society http://www.spatialstatistics.info

-------------- next part --------------
A non-text attachment was scrubbed...
Name: signature.asc
Type: application/pgp-signature
Size: 490 bytes
Desc: OpenPGP digital signature
URL: <https://stat.ethz.ch/pipermail/r-sig-geo/attachments/20150304/41222c5d/attachment.bin>