[R-sig-Geo] units for spatial range in stvariogram gstat

[Edzer Pebesma]

Your email is not nearly enough for a reader to figure out what you did.
However, if your data are long/lat, and you instructed gstat about that
(i.e., proj4string(pm10_sp) indicates coordinates are degrees) then
gstat computes and returns distances in km.

On 17/05/17 20:56, sara osama wrote:
> 
> Dear All,
> I have question concerning the unit of measurement for the range
> parameter in the fit.stvariogram in gstat, i have fitted the following
> spatio temporal variogram for data on monthly averages pf pm10 and the
> longitude and latitude are in decimel format
>  
>> pm10_sp
> SpatialPoints:
>      longitude latitude
> 1     30.92500 29.95300
> 61    31.36000 30.26000
> 121   31.33300 29.84720
>  and this is the commands for fitting the variogram
>> varpm10 <- variogramST(lnpm10only~1,data=lnpm10_stfdf,cutoff=0.8,assumeRegular=T,na.omit=T)
>> plot(varpm10,map=F)
>> sumMetric <- vgmST("sumMetric", space = vgm(psill=5,"Mat", range=50, nugget=0),time = vgm(psill=500,"Mat", range=50, nugget=0,kappa=0.3), joint = vgm(psill=10,"Mat", range=100, nugget=1), stAni=200)
>> sumMetric_Vgm <- fit.StVariogram(varpm10, sumMetric, method="L-BFGS-B",lower=pars.l,upper=pars.u)
>> plot(varpm10,sumMetric_Vgm,map=F)
>  
>> extractPar(sumMetric_Vgm)
>       sill.s      range.s     nugget.s       sill.t      range.t    
> nugget.t
>   1.73598444  50.63845035   0.03212857   0.01570379  49.99811448  
> 0.00000000
>      sill.st <http://sill.st>     range.st <http://range.st>   
> nugget.st <http://nugget.st>         anis
>   0.00000000 100.00004052   0.09151787 200.00000000
>  
> -- 
> now i want to know the units for these parameters in order to be able to
> interpret it for example is it in km or m.
>  
> I really appreciate any help that I deeply need
>  
> Best Regards
> Sara
> 
> 	Faculty of Economics & Political Science
> Cairo University
> 
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-- 
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/

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