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rlatticelme4

Can not change lay-out of dotplot() (lattice package) based on ranef(lmerMod)

We're trying to use dotplot to create a caterpillarplot based on the random effect structure of a lmerMod object created by lmer() in the lme4 package.

The plot itself is created perfectly fine, but when trying to change the lay-out errors occur.

Sample of code without lay-out instructions:

all_bv_C <- lmer(RQ_EvT_A ~ SD_Lft_M_Cat4 + SD_Opl_M_Cat3 + OV_Gez_M_4 +   (1|VSVnr), data=BV2, REML=TRUE)

random <- ranef(all_bv_C, condVar = TRUE)

dotplot(randoms, scales = list(x = list(relation = 'free')))

This creates the plot:

dotplot

We wish to change the title, axis labels and the color palette. For example, to change the title, the usual syntax would be

dotplot(randoms, scales = list(x = list(relation = 'free')), main="Title")

This throws the error:

Error in if (main) nx : argument is not interpretable as logical

We've been unable to get around this error. Everywhere we looked, this should work for any dotplot usage. Can anyone shed some light?

P.S.: We're using dotplot() over ggplot() due to some irregularities in extracting the random effect structure into a data frame as would be suggested here: ggCaterpillar. The function specified throws a NULL due to:

pv   <- attr(x, "postVar")

We've also tried other routes for extracting the variance/covariance matrix to adapt the function, but felt that dotplot was the easier route after fumbling for a day.

Solution

  • You can not here without changing the code. Looking at the source code of the S3 method dotplot for ranef.mer class:

    getS3method("dotplot","ranef.mer")

    You can not set the titles suing arguments. If you look in the function in some line it is written explicitly:

     mtit <- if (main) nx

    where nx is the names(x)( your ranef object).

    So if you do somthing like :

    names(randoms) <- "Title" 
dotplot(randoms)

    the plot title will change. But this is a hack. Better here to change the code of the function and customize it as you like.