[SOLVED] Add measurement uncertainty for kriging

Any question regarding the Interpolation method using Kriging

[SOLVED] Add measurement uncertainty for kriging

Hi all,

I would like to consider measurement uncertainty for kriging. Have you done this before?
Is there any option in the kriging function to add this uncertainty?

Thanks a lot,
Best,

Alicia
AliciaGressent

Posts: 2
Joined: Thu Oct 18, 2018 10:16 am

Re: Add measurement uncertainty for kriging

Hi Alicia

There is an option in RGeostats which offers you the possibility to take into account the variance of measurement error (VME) while kriging.
You have to add a variable in your input database using the locator "v" which contains VME values for each sample.

Here is an example with two points (the first one with no measurement error and the second one with a big one).
Hope this helps !

Code: Select all
`library(RGeostats)# Variogram model (exponential)model = model.create(2,range=20)# Targets gridgrid = db.create(nx=c(100,100))# Neighborhood (unique)neigh = neigh.create(type=0)# Input datasetdat = db.create(x1=c(20,30),x2=c(50,50),z1=c(-1,1))# Simple kriging without measurement errorres1 = kriging(dat,grid,model,neigh,uc="",mean=0)plot(res1,title="Kriging without VEM",pos.legend=1)plot(dat,add=T,pos.legend=7)# Add measurement error on the second point onlydatm = db.add(dat,error=c(0,100),loctype="v")# Simple kriging with measurement errorres2 = kriging(datm,grid,model,neigh,uc="")plot(res2,title="Kriging with VEM",pos.legend=1)plot(datm,add=T,name.prop="error",pos.legend=7)`

KrigWithoutVEM.png (7.17 KiB) Viewed 600 times

KrigwithVEM.png (7.57 KiB) Viewed 600 times
Fabien Ors

Posts: 168
Joined: Thu Sep 20, 2012 1:07 pm

Re: [SOLVED] Add measurement uncertainty for kriging

Hi Fabien ,

I know I posted this VME question long time ago and it works pretty well but I was wondering how this VME is implemented in the kriging? Could you please tell me more about this?

Thank you very much,
Alicia
AliciaGressent

Posts: 2
Joined: Thu Oct 18, 2018 10:16 am

Re: [SOLVED] Add measurement uncertainty for kriging

Dear Alicia,

The variance of measurement error of each sample data is added to the corresponding diagonal term of the covariance matrix before solving the kriging system.

Hope this helps,
Best regards
Fabien Ors