plotfeaturetypeCounts {systemPipeR} | R Documentation

## Plot read distribution across genomic features

### Description

Function to visualize the distribution of reads across different feature types for many alignment files in parallel. The plots are stacked bar plots representing the raw or normalized read counts for the sense and antisense strand of each feature. The graphics results are generated with `ggplot2`. Typically, the expected input is generated with the affiliated `featuretypeCounts` function.

### Usage

    plotfeaturetypeCounts(x, graphicsfile, graphicsformat = "pdf", scales = "fixed", anyreadlength = FALSE,
                          drop_N_total_aligned = TRUE, scale_count_val = 10^6, scale_length_val = NULL)

### Arguments

`x` | `data.frame` with feature counts generated by the `featuretypeCounts` function.
`graphicsfile` | Path to file where to write the output graphics. Note, the function returns the graphics instructions from `ggplot2` for interactive plotting in R. However, due to the complexity of the graphics generated here, the finished results are written to a file directly.
`graphicsformat` | Graphics file format. Currently, supported formats are: pdf, png or jpeg. Argument accepts one of them as character string.
`scales` | Scales setting passed on to the `facet_wrap` function of `ggplot2`. For details see `ggplot2::facet_wrap`. The default `fixed` assures a constant scale across all bar plot panels, while `free` uses the optimum scale within each bar plot panel. To evaluate plots in all their details, it may be necessary to generate two graphics files one for each scaling option.
`anyreadlength` | If set to `TRUE` read length specific read counts will be summed up to a single count value to plot read counts for any read length. Otherwise the bar plots will show the counts for each read length value.
`drop_N_total_aligned` | If set to `TRUE` the special feature count `N_total_aligned` will not be included as a separate feature in the plots. However, the information will still be used internally for scaling the read counts to a fixed value if this option is requested under the `scale_count_val` argument.
`scale_count_val` | Scales (normalizes) the read counts to a fixed value of aligned reads in each sample such as counts per million aligned reads (default is 10^6). For this calculation the `N_total_aligned` values are used that are reported in the input `data.frame` generated by the upstream `featuretypeCounds` function. Assign `NULL` to turn off scaling by aligned reads.
`scale_length_val` | Allows to adjust the raw or scaled read counts to a constant length interval (e.g. `scale_length_val=10^3` in bps) considering the total genomic length of the corresponding feature type. The required genomic length information for each feature type is obtained from the `Featuretypelength` column of the input `data.frame` generated by the `featuretypeCount` function. To turn off feature length adjustment, assign `NULL` (default).

### Value

The function returns bar plot graphics for aligned read counts with read length resolution if the input contains this information and argument `anyreadlength` is set to `FALSE`. If the input contains counts for any read length and/or `anyreadlength=TRUE` then there will be only one bar per feature and sample. Due to the complexity of the plots, the results are directly written to file in the chosen graphics format. However, the function also returns the plotting instructions returned by `ggplot2` to display the result components using R's plotting device.

### Author(s)

Thomas Girke

### See Also

`featuretypeCounts`, `genFeatures`

### Examples

    ## Construct SYSargs object from param and targets files
    param <- system.file("extdata", "tophat.param", package="systemPipeR")
    targets <- system.file("extdata", "targets.txt", package="systemPipeR")
    args <- systemArgs(sysma=param, mytargets=targets)

    ## Not run:
    ## Features from sample data of systemPipeRdata package
    library(GenomicFeatures)
    file <- system.file("extdata/annotation", "tair10.gff", package="systemPipeRdata")
    txdb <- makeTxDbFromGFF(file=file, format="gff3", organism="Arabidopsis")
    feat <- genFeatures(txdb, featuretype="all", reduce_ranges=TRUE, upstream=1000, downstream=0, verbose=TRUE)

    ## Generate and plot feature counts for specific read lengths
    fc <- featuretypeCounts(bfl=BamFileList(outpaths(args), yieldSize=50000), grl=feat, singleEnd=TRUE, readlength=c(74:76,99:102), type="data.frame")
    p <- plotfeaturetypeCounts(x=fc, graphicsfile="featureCounts.pdf", graphicsformat="pdf", scales="fixed", anyreadlength=FALSE)

    ## Generate and plot feature counts for any read length
    fc2 <- featuretypeCounts(bfl=BamFileList(outpaths(args), yieldSize=50000), grl=feat, singleEnd=TRUE, readlength=NULL, type="data.frame")
    p2 <- plotfeaturetypeCounts(x=featureCounts2, graphicsfile="featureCounts2.pdf", graphicsformat="pdf", scales="fixed", anyreadlength=TRUE)

    ## End(Not run)

[Package systemPipeR version 1.26.3 Index]