Plot Bamstats

plot-bamstats

Perl-based visualization tool bundled with samtools for plotting BAM alignment statistics.

Quick Start

• Command: plot-bamstats [options] file.bam.bc
• Local executable: /home/vimalinx/miniforge3/envs/bio/bin/plot-bamstats
• Expected input: samtools stats output, historically called bamcheck

When To Use This Tool

• Visualizing output from samtools stats as graphical plots
• Generating publication-quality alignment statistic figures
• Merging multiple bamstats files into one stream before plotting
• Incorporating reference GC expectations through -s / -r

Common Patterns

# 1) Basic BAM QC plotting
samtools stats aln.bam > aln.bam.bc
plot-bamstats -p outdir/ aln.bam.bc

# 2) Merge multiple bamstats files to stdout
plot-bamstats -m sample1.bc sample2.bc > merged.bc

# 3) Prepare reference GC statistics for later plotting
plot-bamstats -s ref.fa
plot-bamstats -p outdir/ -r ref.fa.gc aln.bam.bc

Recommended Workflow

1. Produce a clean samtools stats file first and keep it alongside the source BAM.
2. Decide whether you want a fresh plot directory (-p outdir/) or a simple prefixed file set.
3. If GC bias matters, precompute reference stats with -s and pass the resulting .gc file back with -r.
4. Inspect the generated PNG/HTML outputs for insert size, coverage, GC, mismatch, and length-shape anomalies.

Guardrails

• Local runtime is currently blocked before normal help or plotting because Perl cannot load URI::Escape.pm.
• The built-in source help says this parser expects samtools stats output, not raw BAM files and not samtools flagstat.
• The script also relies on gnuplot for figure generation; plan for both Perl-module and plotting-tool dependencies.
• --help could not be exercised cleanly here because the missing Perl module aborts compilation first; the available option surface was recovered from the script's own error() usage block.
• -m is a merge-to-stdout mode, so do not expect plots when that switch is present.