我正在研究时空数据。数据采用 STFDF 结构。
我正处于应用变异函数并尝试从看起来像这样的变异函数图中确定块金、窗台和范围的阶段。
plot(vario, main="Flow")
和plot(vario,map=FALSE, main="Spatio-temporal correlation")
_plot(vario,wireframe=T, main="Spatio-temporal correlation")
如何获得可以定义范围、窗台和金块的地块!!我无法从这些图中定义我的参数。我使用了 variogramST 函数并尝试了 variogram 函数,但两者都无法生成我需要的图。
vario<-variogramST(Flow~1,data=data,tunit="hours",assumeRegular=F,na.omit=T)
有什么方法可以定义 Range、Nugget 和 sill?
####### separable model, least squares fit
separableModel <- vgmST("separable",space=vgm(0.9,"Exp",100,0.1),time=vgm(0.9,"Exp",1000,0.1),sill=40)
separable_fit <- fit.StVariogram(model=separableModel,object=vario)
plot(vario,separable_fit,all=T,map=F)
attr(separable_fit,"MSE") # calculate the Mean Absolute Error
### product sum model, least squares fit
ProductSum <- vgmST("productSum",space =vgm(psill= 15000,"Exp",range= 0.07, nugget= 0),time=vgm(psill= 7500,"Exp",range= 0.07, nugget=0),k=0.000649771173341919)
ProductSum_fit <- fit.StVariogram(model=ProductSum,object=vario)
ProductSum_fit
attr(ProductSum_fit,"MSE")
plot(vario,ProductSum_fit,all=T,map=F)
plot(vario,ProductSum_fit,all=T)
plot(vario,ProductSum_fit, all=T, wireframe=T)
#### product sum model, manual fit
ProductSum_man <- vgmST("productSum",space=vgm(7500,"Exp",2e5,0,add.to=vgm(10,"Exp",9e3,0)), time=vgm(7500,"Exp",800,9.5,add.to=vgm(0,"Exp",850,0)),k=0.035)
ProductSum_man_fit <- fit.StVariogram(model=ProductSum_man,object=vario)
attr(ProductSum_man_fit,"MSE")
plot(vario,ProductSum_man_fit,all=T,map=F)
plot(vario,ProductSum_man_fit,all=T)