[R-sig-Geo] R-stats - GRASS6

[Markus Neteler]

Dear Roger,

On Tue, May 31, 2005 at 06:53:31PM +0200, Roger Bivand wrote:
> On Tue, 31 May 2005, Markus Neteler wrote:
> 
> > Dear list members,
> > 
> > I am currently trying out the new GRASS 6/R-stats interface.
> > I installed all software today (R-2.1.0, all interfaces, using
> > GRASS 6.1-CVS).
> > 
> > There is a little problem which I don't understand:
> > 
> > > library(spgrass6)
> > > G <- gmeta6()
> > > str(G)
> > List of 28
> >  $ GISDBASE         : chr "/ssi0/ssi/neteler/grassdata"
> >  $ LOCATION_NAME    : chr "spearfish60"
> >  $ MAPSET           : chr "neteler"
> >  $ GRASS_DB_ENCODING: chr "utf-8"
> >  $ DEBUG            : chr "0"
> >  $ MONITOR          : chr "x0"
> >  $ GRASS_GUI        : chr "text"
> >  $ projection       : chr "1 (UTM)"
> > [...]
> > 
> > > system("r.info -t landcover.orig")
> > datatype=CELL
> > > landcover <- readCELL6sp("landcover.orig", cat = TRUE)
> > Error in "names<-.default"(`*tmp*`, value = "landcover.orig") :
> >         'names' attribute [1] must be the same length as the vector [0]
> 
> I can't replicate this, I'm afraid (R 2.1.0, Linux, sp 0.7-7, spgrass6
> 0.1-4 (from CVS on sourceforge, GRASS 6.0.0 release). I don't think the sp 
> or spgrass6 versions make a difference. 
> 
> Could you say debug(readCELL6sp) and re-run this please - that should show 
> which line is failing. Once we know that, please check the arguments to 
> that function for sanity. I don't think it is important, but I'm running 
> under LANG=en_GB ; export LANG, not UTF8. My current guess is that the 
> problem is in:
> 
> res <- read.asciigrid(tmpfl, colname = vname, proj4string = p4)
> 
> where vname is the layer name. If you additionally do 
> debug(read.asciigrid), it may fail at: names(df) = colname - please see 
> what is in colname, and if length(colname) is the same as length(df). One 
> possibility is that there is something amiss in read.asciigrid().
> 
> The landcover.orig layer is strange because there are no category labels 
> at all, so:

[... took the wrong landuse map, but it doesn't change ...]

> library(spgrass6)
Loading required package: rgdal
Loading required package: abind
Loading required package: pixmap
Geospatial Data Abstraction Library extensions to R successfully loaded
Loading required package: sp
> G <- gmeta6()

> landcover <- readCELL6sp("landcover.30m", cat = TRUE)
Error in "names<-.default"(`*tmp*`, value = "landcover.30m") :
        'names' attribute [1] must be the same length as the vector [0]
> debug(readCELL6sp)

> system("r.stats -l -q landcover.30m | head -20")
11 Open Water
21 Low Intensity Residential
22 High Intensity Residential
23 Commercial/Industrial/Transportation
31 Bare Rock/Sand/Clay
32 Quarries/Strip Mines/Gravel Pits
41 Deciduous Forest
42 Evergreen Forest
43 Mixed Forest
51 Shrubland
71 Grasslands/Herbaceous
81 Pasture/Hay
82 Row Crops
83 Small Grains
85 Urban/Recreational Grasses
91 Woody Wetlands
92 Emergent Herbaceous Wetlands
* no data

> landcover <- readCELL6sp("landcover.30m", cat = TRUE)
debugging in: readCELL6sp("landcover.30m", cat = TRUE)
debug: {
[...]
}
Browse[1]>
debug: tmpfl <- tempfile()
Browse[1]>
debug: system(paste("r.out.arc input=", vname, " output=", tmpfl, sep = ""))
Browse[1]>
debug: library(sp)
Browse[1]>
debug: p4 <- CRS(system("g.proj -j -f", intern = TRUE))
Browse[1]>
debug: res <- read.asciigrid(tmpfl, colname = vname, proj4string = p4)
Browse[1]>
debug: if (cat) {
    cats <- strsplit(system(paste("r.stats -l -q", vname), intern = TRUE),
        " ")
    catnos <- sapply(cats, function(x) x[1])
    catlabs <- sapply(cats, function(x) paste(x[-1], collapse = " "))
    if (any(!is.na(match(catnos, "*")))) {
        isNA <- which(catnos == "*")
        catnos <- catnos[-isNA]
        catlabs <- catlabs[-isNA]
    }
    res at data[, 1] <- factor(res at data[, 1], levels = catnos, labels = catlabs)
} else {
    res at data[, 1] <- as.integer(res at data[, 1])
}
Browse[1]>
debug: cats <- strsplit(system(paste("r.stats -l -q", vname), intern = TRUE),
    " ")
Browse[1]>
debug: catnos <- sapply(cats, function(x) x[1])
Browse[1]>
debug: catlabs <- sapply(cats, function(x) paste(x[-1], collapse = " "))
Browse[1]>
debug: if (any(!is.na(match(catnos, "*")))) {
    isNA <- which(catnos == "*")
    catnos <- catnos[-isNA]
    catlabs <- catlabs[-isNA]
}
Browse[1]>
debug: isNA <- which(catnos == "*")
Browse[1]>
debug: catnos <- catnos[-isNA]
Browse[1]>
debug: catlabs <- catlabs[-isNA]
Browse[1]>
debug: res at data[, 1] <- factor(res at data[, 1], levels = catnos, labels = catlabs)
Browse[1]>
Error in "names<-.default"(`*tmp*`, value = "landcover.30m") :
        'names' attribute [1] must be the same length as the vector [0]
>  


> debug(read.asciigrid)
> undebug(readCELL6sp)

> landcover <- readCELL6sp("landcover.30m", cat = TRUE)
[...]
Browse[1]>
debug: df = data.frame(map)
Browse[1]>
debug: names(df) = colname
Browse[1]> length(colname)
[1] 1
Browse[1]> length(df)
[1] 1
Browse[1]> colname
[1] "landcover.30m"
Browse[1]> df
[...all values...]

> str(df)
`data.frame':   302418 obs. of  1 variable:
 $ map: num  NA NA NA NA NA NA NA NA NA NA ...
Browse[1]>
debug: grid = GridTopology(c(xllcenter, yllcenter), rep(cellsize, 2),
    c(ncols, nrows))
Browse[1]>
debug: SpatialGridDataFrame(grid, data = df, proj4string = proj4string)
Browse[1]>
exiting from: read.asciigrid(tmpfl, colname = vname, proj4string = p4)
Error in "names<-.default"(`*tmp*`, value = "landcover.30m") :
        'names' attribute [1] must be the same length as the vector [0]
>    

I don't know if this is already helpful.

Best regards

 Markus