[BioC] rtrack export.wig

[Vince Schulz]

I would like to export wig variablestep files using the rtrack package.  I get an error if I export 
files that have "overlapping" features on different chromosomes.  For example, I can't export this:

chr1	NimbleScan	CHR01FS000924213	924213	924214	-0.192999968716105	.	.	CHR01FS000924213
chr9	NimbleScan	CHR09FS138569971	924211	924213	-0.090919369857934	.	.	CHR09FS138569971

 > gffFile <- import.gff("test.gff", version = c("1"), genome = "hg18")
 > export.wig(gffFile, "test.wig", dataFormat = "variableStep")
Error in export.ucsc(object, con, subformat, ...) :
   Track not compatible with WIG format: Overlapping features must be on separate strands

But I can export

chr1	NimbleScan	CHR01FS000924213	924213	924214	-0.192999968716105	.	.	CHR01FS000924213
chr9	NimbleScan	CHR09FS138569971	924211	924212	-0.090919369857934	.	.	CHR09FS138569971

Note 924213 change to 924212 in second working version

Could this be fixed?

Thanks,

Vince

sessionInfo()
R version 2.8.0 (2008-10-20)
i386-pc-mingw32

locale:
LC_COLLATE=English_United States.1252;LC_CTYPE=English_United States.1252;LC_MONETARY=English_United 
States.1252;LC_NUMERIC=C;LC_TIME=English_United States.1252

attached base packages:
[1] tools     stats     graphics  grDevices utils     datasets  methods
[8] base

other attached packages:
[1] rtracklayer_1.2.2 RCurl_0.92-0      Biobase_2.2.2

loaded via a namespace (and not attached):
[1] Biostrings_2.10.21 grid_2.8.0         IRanges_1.0.14     lattice_0.17-15
[5] Matrix_0.999375-16 rJava_0.6-3        XML_1.94-0.1