Gviz - adjust track height

[abisko00]

Dear all,

I have a probably trivial problem where I need a hint into the right direction:

I am trying to visualize RNA-seq data in Gviz (nice!). I have two bam files loaded as AlignmentsTrack (just coverage and sashimi, no reads). Individually, they fill the square plotting area completey (the Y-axis is scaled to fill all available space). I can also add GenomeAxisTrack and a BioMartGeneRegionTrack, which reduces the height accordingly. But when I add the second AlignmentsTrack, the plot no longer scales in y-direction and I get a very narrow band in the middle of my square plotting area (maybe 25% of the available space).

How can I scale the two AlignmentsTracks to use more y-space in the plotting area? The parameters "sizes" or any type of "height" parameter just affects the ratio within the band, but not the overall size.

gTrack<-GenomeAxisTrack()
alTrack<-AlignmentsTrack(range='WT.bam',genome='hg19', name='Wildtype', chromosome='chr8',ispaired=T)
alTrack2<-AlignmentsTrack(range='Mut.bam',genome='hg19', name='Mutant', chromosome='chr8',ispaired=T)
bmt<-BiomartGeneRegionTrack(genome='hg19',chromosome='chr8',start=afrom,end=ato,filter=list(with_ox_refseq_mrna=T),stacking='squish',showExonId=F)
plotTracks(c(gTrack,bmt,alTrack,alTrack2),from=afrom,to=ato,type=c('coverage','sashimi'))

[stianlagstad]

Did you have the same problem as I'm experiencing here? If so, did you ever find a solution?

Edit: If that was your problem, the solution is in the thread I linked to

[abisko00]

Hi,

thanks for pointing me to your thread. Meanwhile, I have given up on this problem, but although my plot is slightly different, I'll give the max.height parameter a try.

Markus

[stianlagstad]

If you provide a runnable code example (not dependent on your own data sets), it will be much easier to understand what the problem is See some tips for how to do that here: How to create a Minimal, Complete, and Verifiable example

[abisko00]

You could also use the gapped.bam from the Gviz sample data twice:

bamFile<-system.file("extdata/gapped.bam",package="Gviz")
gTrack<-GenomeAxisTrack()
alTrack<-AlignmentsTrack(range=bamFile,genome='hg19', name='Wildtype', chromosome='chr12',ispaired=T)
alTrack2<-AlignmentsTrack(range=bamFile,genome='hg19', name='Mutant', chromosome='chr12',ispaired=T)
plotTracks(c(gTrack,alTrack,alTrack2),from=2965000,to=3000000,type=c('coverage','sashimi'))

Setting the min.height parameter did not change it, unfortunately.

[stianlagstad]

Executable code - great! So this code:

bamFile <- system.file(
  "extdata/gapped.bam",
  package = "Gviz")
gTrack <- GenomeAxisTrack()
alTrack<- AlignmentsTrack(
  range = bamFile,
  genome = 'hg19',
  name = 'Wildtype',
  chromosome = 'chr12',
  ispaired = T)
alTrack2 <- AlignmentsTrack(
  range = bamFile,
  genome = 'hg19',
  name = 'Mutant',
  chromosome = 'chr12',
  ispaired = T)
plotTracks(
  c(gTrack, alTrack, alTrack2),
  from = 2965000,
  to = 3000000,
  type = c('coverage', 'sashimi'))

Produces this plot for me:



To me it looks like the available y-space is used. What exactly is the problem?

[abisko00]

I attached what it produces on my system. I saved it as pdf, though, because that format is easiest to use in Illustrator.

pdf('test.pdf')
plotTracks(
  c(gTrack, alTrack, alTrack2),
  from = 2965000,
  to = 3000000,
  type = c('coverage', 'sashimi'))
dev.off()

EDIT: png gives the same

[stianlagstad]

I see. I'm also experiencing these issues when exporting Gviz plots to pdf. Maybe you could try using svg instead? I don't know whether this is a problem with Gviz or with the pdf device, but you could ask a question over at the Bioconductor support site. The Gviz author, Florian Hahne, is responsive to questions there.

[abisko00]

How did you produce your image? I am relatively new to R and completely autodidactic. Maybe I miss a very simple setting. But thanks anyway!

[stianlagstad]

If you mean the plot in my post above, I exported it as a png image from RStudio. But you could also do this:

png(
  'test.png',
  width = 600,
  height = 300)
plotTracks(
  c(gTrack, alTrack, alTrack2),
  from = 2965000,
  to = 3000000,
  type = c('coverage', 'sashimi'))
dev.off()

Or you could switch png with svg, pdf or something else. A list of available plotting devices can be found here.

[abisko00]

Solved

Normally, I hate these kind of solutions, because you learn nothing from them, but after you've shown that the code is working, I did a clean install of R and Gviz and here we go!

Thanks!