r-bioc-biovizbase 1.12.3-1 / usr / lib / R / site-library / biovizBase / doc / intro.Rnw

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\title{An Introduction to \biovizBase{}}
\author{Tengfei Yin, Michael Lawrence, Dianne Cook}
\date{\today}

\begin{document}
\maketitle
\newpage
\tableofcontents
\newpage

<<options,echo=FALSE>>=
options(width=72)
@

\section{Introduction}

The \biovizBase{} package is designed to provide a set of utilities and
color schemes serving as the basis for visualizing biological data,
especially genomic data. Two other packages are currently built on this
package, a static version of graphics is provided by the package \ggbio{},
and an interactive version of graphics is provided by \visnab{}(Currently not released).

In this vignette, we will introduce those color schemes and different
utilities functions using simple examples and data sets. Utilities
includes functions that precess the raw data, validate names,
add attributes, and generate summaries such as fragment length,
GC content, and mismatch information.

\section{Color Schemes}
The \biovizBase{} package aims to provide a set of default color schemes
for biological data, based on the following principles.
\begin{itemize}
\item Make biological sense.  Data is displayed in a way that is
  similar to observed results under the microscope. (Example: giemsa
  stain results)
\item Generate aesthetically pleasing colors based on well-defined
  color sets like \emph{color brewer}
  \footnote{\url{http://colorbrewer2.org/}}. Produce the appropriate
  color for \emph{sequential, diverging, and qualitative} color
  schemes.
\item Accommodate colorblind vision by creating color pallets that
  pass the color blind check on the \emph{Vischeck} website
  \footnote{\url{http://www.vischeck.com/}} or use palette from
  package \Rpackage{dichromat} or use color-blind safe color palette
  checked by \emph{ColorBrewer}
  website\footnote{\url{http://colorbrewer2.org/}}. There are three
  types of colorblind checking strategy defined on these website.
  \begin{description}
     \item[Deuteranope] a form of red/green color deficit; 
     \item[Protanope] another form of red/green color deficit;
     \item[Tritanope] a blue/yellow deficit- very rare.
  \end{description}
\end{itemize}

Our color scheme try to pass color-blind checking points to make sure
all the users can tell the difference between groups of data
displayed.  To make the implementation easy, we most time just use
\Rpackage{dichromat} to check this, \Rpackage{dichromat} collapses
red-green color distinctions to approximate the effect of the two
common forms of red/green color blindness, protanopia and
deuteranopia.  Or we could simply implement proved color-blind safe
palette from \Rpackage{dichromat} or \Rpackage{RColorBrewer}.

All color schemes have a general color generating function and a
default color generating function.  They are automatically stored in
\Rfunction{options} as default when loading the package. Other
packages built on \biovizBase{} can use the default color scheme,
ensuring consistent color themes across all static and interactive
graphics.  Users may also change the default color in the
\Rfunction{options} to personalize the global color scheme to fit
their needs.


@ 
<<color-scheme-option>>=
library(biovizBase)
## library(scales)

@ %def 

\subsection{Colorblind Safe Palette}
For graphics, it's important to make sure most people can tell the
difference between colors on the plots, even for people with deficient
or anomalous red-green vision. 

We will add more and more colorblind safe palette gradually, now we
only supported palettes from two packages, \Rpackage{dichromat} or
\Rpackage{RColorBrewer}. However, \Rpackage{RColorBrewer} doesn't
provide information about colorblind palette. So we need to check
manually on \textit{ColorBrewer} website, and add this information
with the palette information. For \Rpackage{dichromat} package, it
doesn't have a palette information like \Rcode{brewer.pal.info}, which
contains three different types, \textbf{qual, div, seq} representing
quality, divergent and sequential respectively, and also missing max
colors information, so we integrate all these information and generate
three palette information.

\begin{itemize}
\item \Robject{brewer.pal.blind.info} provides only colorblind safe
  palette subset.
\item \Robject{dichromat.pal.blind.info} provides colorblind safe
  palette with category information and max color allowed.
\item \Robject{blind.pal.info} integrate first two, provides a general
  palette information with extra column like pal.id, which used for
  function \Rfunction{colorBlindSafePal} as index for arguments
  \Rfunarg{palette} or maxcolors for allowed number of
  color. \textit{pkg} providing information about which package it is
  defined.
\end{itemize}
@ 
<<color-pal-info>>=
head(blind.pal.info)
@ %def 

Then we defined a color generating function
\Rfunction{colorBlindSafePal}, this function reading in a palette
argument which could be a index number or names for palette defined in
\Robject{blind.pal.info}. And return a color generating function, a
\Rfunarg{repeatable} argument will control, for number over max color
numbers required, does it simply repeat it or just providing limited
number of colors.

@ 
<<colorBlindPal>>=
## with no arguments, return blind.pal.info
head(colorBlindSafePal())
## 
mypalFun <- colorBlindSafePal("Set2")
## mypalFun(12, repeatable = FALSE) #only three
mypalFun(11, repeatable = TRUE)  #repeat
@ %def 

To Collapses red-green color distinctions to approximate the effect of
the two common forms of red- green color blindness, protanopia and
deuteranopia, we can use function \Rfunction{dichromat} from package
\Rpackage{dichromat}, this save us the time to 

\begin{figure}[h!t!p!b]
  \centering
@ 
<<color-dichromat, fig = TRUE>>=
## for palette "Paried"
mypalFun <- colorBlindSafePal(21)   
par(mfrow = c(1, 3))
showColor(mypalFun(4))
library(dichromat)
showColor(dichromat(mypalFun(4), "deutan"))
showColor(dichromat(mypalFun(4), "protan"))
@ %def   
\caption{Checking colors with two common type of color blindness. The
  first one is normal perception, second one for deuteranopia and last
  one for protanopia. Since we are using selected color palettes in
  this package, it should be fine with those types of blindness.}
  \label{fig:dichromat}
\end{figure}

We only show this as an examples and won't compare all other color
schemes in the following sections. Please notice that
\begin{itemize}
\item If the categorical data contains many levels like amino acid,
  people cannot easily tell the difference anyway, we did the trick to
  simply repeat the colors. This might be useful for many other cases
  like grand linear view for chromosomes, since if the viewed orders of
  chromosomes is fixed it's OK to use repeated colors since they are
  not going to be layout as neighbors anyway.
\item For schemes like cytobands, we try to follow the biological
  sense, in this case, we don't really check the color blindness.
\end{itemize}



\subsection{Cytobands Color}
Chemically staining the metaphase chromosomes results in a alternating
dark and light banding pattern, which could provide information about
abnormalities for chromosomes. Cytogenetic bands could also provide
potential predictions of chromosomal structural characteristics, such
as repeat structure content, CpG island density, gene density, and GC
content.

\biovizBase{} package provides utilities to get ideograms from the UCSC
genome browser, as a wrapper around some functionality from
\Rpackage{rtracklayer}. It gets the table for \emph{cytoBand} and stores
the table for certain species as a \Robject{GRanges} object.

We found a color setting scheme in package \Rpackage{geneplotter},
and we implemented it in biovisBase.

The function .cytobandColor will return a default color set. You could
also get it from \Rfunction{options} after you load \biovizBase{}
package.

And we recommended function \Rfunction{getBioColor} to get the color
vector you want, and names of the color is biological categorical
data. This function hides interval color genenerators and also the
complexity of getting color from options. You could specify whether
you want to get colors by default or from options, in this way, you
can temporarily edit colors in options and could change or all the
graphics. This give graphics a uniform color scheme.

@ 
<<cytoband-color>>=
getOption("biovizBase")$cytobandColor
getBioColor("CYTOBAND")
## differece source from default or options.
opts <- getOption("biovizBase")
opts$DNABasesNColor[1] <- "red"
options(biovizBase = opts)
## get from option(default)
getBioColor("DNA_BASES_N")
## get default fixed color
getBioColor("DNA_BASES_N", source = "default")
seqs <- c("A", "C", "T", "G", "G", "G", "C")
## get colors for a sequence.
getBioColor("DNA_BASES_N")[seqs]
@ %def 

You can check the color scheme by calling the
\Rfunction{plotColorLegend} function.  or the \Rfunction{showColor}.


\begin{figure}[h!t!p]
  \centering
@ 
<<cytoband-color-legend, fig = TRUE>>=
cols <- getBioColor("CYTOBAND")
plotColorLegend(cols, title  = "cytoband")
@ %def 
  \caption{Legend for cytoband color}
  \label{fig:cytoband}
\end{figure}


\subsection{Strand Color}
In the \Robject{GRanges} object, we have \Robject{strand} which
contains three levels, \textbf{+, -, *}. We are using a qualitative
color set from \emph{Color Brewer} and check with \Rpackage{dichromat}
as Figure\ref{fig:strand} shows, and we can see that this color set
passes all three types of colorblind test. Therefore it should be a
safe color set to use to color strand.

\begin{figure}[h!t!p]
  \centering
  @ 
<<strand-color, fig = TRUE>>=
par(mfrow = c(1, 3))
cols <- getBioColor("STRAND")
showColor(cols)
showColor(dichromat(cols, "deutan"))
showColor(dichromat(cols, "protan"))
@ %def 
  \caption{Colorblind vision check for color of strand}
  \label{fig:strand}
\end{figure}

\subsection{Nucleotides Color}
We start with the five most used nucleotides, \textbf{A,T,C,G,N}, most
genome browsers have their own color scheme to represent nucleotides, We
chose our color scheme based on the principles introduced
above. Since in genetics, \emph{GC-content} usually has special
biological significance because GC pair is bound by three hydrogen
bonds instead of two like AT pairs. So it has higher thermostability
which could result in different significance, like higher annealing
temperature in PCR. So we hope to choose warm colors for \textbf{G,C}
and cold colors for \textbf{A,T}, and a color in between to represent
\textbf{N}.  They are chosen from a diverging color set of \emph{color
  brewer}. So we should be able to easily tell the GC enriched region.
Figure \ref{fig:ne} shows the results from \Rpackage{dichromat},
and we can see this color set passes all two types of the colorblind
test. It should be a safe color set to use to color the five most used
nucleotides.

@ 
<<base-color>>=
getBioColor("DNA_BASES_N")

@ %def 

\begin{figure}[h!t!p]
  \centering
@ 
<<ne-dichromat, fig = TRUE>>=
par(mfrow = c(1, 3))
cols <- getBioColor("DNA_BASES_N", "default")
showColor(cols, "name")
cols.deu <- dichromat(cols, "deutan")
names(cols.deu) <- names(cols)
cols.pro <- dichromat(cols, "protan")
names(cols.pro) <- names(cols)
showColor(cols.deu, "name")
showColor(cols.pro, "name")
@ %def 

  \caption{Colorblind vision check for color of nucleotide}
  \label{fig:ne}
\end{figure}

\subsection{Amino Acid Color and Other Schemes}
We also include some other color schemes created based on existing
object in package \Rpackage{Biostrings} and other customized color
scheme.  Please notice that the object name is not the same as the
name in the options.  On the left of \textbf{=}, it's name of object,
most of them are defined in \Rpackage{Biostrings} and on the right,
it's the name in options.

\begin{verbatim}
DNA_BASES_N = "DNABasesNColor"
DNA_BASES = "DNABasesColor"
DNA_ALPHABET = "DNAAlphabetColor"
RNA_BASES_N = "RNABasesNColor"
RNA_BASES = "RNABasesColor"
RNA_ALPHABET = "RNAAlphabetColor"
IUPAC_CODE_MAP = "IUPACCodeMapColor"
AMINO_ACID_CODE = "AminoAcidCodeColor"                     
AA_ALPHABET = "AAAlphabetColor"
STRAND = "strandColor"
CYTOBAND = "cytobandColor"
\end{verbatim}

They all could be retrieved by calling function
\Rfunction{getBioColor}.


\subsection{Future Schemes}
Current color schemes are most generated based on known object in
\R{}, which has a clear definition and classification. But we do have
more interesting events or biological significance need to be color
coded. Like most genome browser, they try to color code many events,
for instance, color the insertion size which is larger/smaller than
the estimated size; for paired RNA-seq data, we may color the paired
reads mapped to a different chromosome. 

We may include more color coded events in this package in next
release.

\section{Utilities}
\biovizBase{} serves as a basis for the visualization of biological data,
especially for genomic data. \Rpackage{IRanges} and
\Rpackage{GenomicRanges} are the two most important infrastructure
packages to manipulate genomic data. They already have lots of useful
and fast utilities for processing genomic data. Some other package
such as \Rpackage{rtracklayer}, \Rpackage{Rsamtools},
\Rpackage{ShortRead}, \Rpackage{GenomicFeatures} provide common I/O
for certain types of biological data and utilities for processing
those raw data. Most of our utilities to be introduced in this section
only manipulate the data in a simple and different way to get them ready
for visualization. Most cases are only useful for visualization work,
like adding brush color attributes to a \Robject{GRanges} object. Some
of the other utilities are responsible for summarizing certain types of
raw data, getting it ready to be visualized. Some of those utilities may be moved to
a separate package later.

\subsection{GRanges Related Manipulation}
\biovizBase{} mainly focuses on visualizing the genomic data, so we
have some utilities for manipulating \Robject{GRanges} object. We are
going to introduce these functions in the flow wing sub-sections.
Overall, we hope to reduce people's work through these common
utilities.

% \subsubsection{Chromosome Name Manipulation}
% We don't have required canonical chromosome name for
% \Robject{seqnames} in \Robject{GRanges}. Most times, we have chromosome
% name with prefix \textbf{chr} in lower case. However, we could come
% across all kinds of other names with prefix \textbf{Chr}, or
% without any prefix at all. This complicates our integration of data
% since we need to check with \Robject{seqnames} before we are able to aggregate
% them or before we can visualize them. A consistent name scheme is very
% important in most graphic packages like \Rpackage{ggplot2}.  For
% example, you are going to fail if you try to overlay two data in
% the same plot which follows a different name schema. Sometimes we
% also need to layout our graphics for genomes in a nice ordered way,
% which requires some sorting/ordering function to re-order our
% \Robject{GRanges} object.


% Function \Rfunction{sortChr} works for \Robject{GenomicRanges}, or
% characters or factor, sort it based on seqnames.  The default is first
% showing numeric seqnames in increasing order, then showing mixed
% letters names in alphabetical. Function \Rfunction{orderChr} return
% an index instead of a \Robject{GenomicRanges} object. The user could also
% provide a model which is a vector of seqnames to sort by.
% @ 
% <<sort-chr>>=
% sort(gr)
% head(sortChr(gr, prefix = "chr"))
% head(orderChr(gr, prefix = "chr"))
% head(sortChr(gr, model = c("chrX", "chr3", "chr1", "chrY", "chr2")))
% sortChr(c("chrX", "chr3", "chr1", "chrY", "chr2"))
% orderChr(c("chrX", "chr3", "chr1", "chrY", "chr2"))
% sortChr(factor(c("chrX", "chr3", "chr1", "chrY", "chr2")))
% orderChr(factor(c("chrX", "chr3", "chr1", "chrY", "chr2")))
% @ %def 


\subsubsection{Adding Disjoint Levels}
@ 
<<sample-gr>>=
library(GenomicRanges)
set.seed(1)
N <- 500
gr <- GRanges(seqnames =
              sample(c("chr1", "chr2", "chr3", "chrX", "chrY"),
                     size = N, replace = TRUE),
              IRanges(
                      start = sample(1:300, size = N, replace = TRUE),
                      width = sample(70:75, size = N,replace = TRUE)),
              strand = sample(c("+", "-", "*"), size = N,
                replace = TRUE),
              value = rnorm(N, 10, 3), score = rnorm(N, 100, 30),
              group = sample(c("Normal", "Tumor"),
                size = N, replace = TRUE),
              pair = sample(letters, size = N,
                replace = TRUE))
@ %def 

This is a tricky question.  For example, for pair-end RNA-seq data, we
may want to put the reads with the same \emph{qname} on the same
level, with nothing falling in between. For better visualization of
the data, we may hope that adding invisible extensions to the reads
will prevent closely neighbored reads from showing up on the same
level.

\Rfunction{addStepping} function takes a
\Robject{GenomicRanges} object and will add an extra column
called \textbf{.levels} to the object.  This function is essentially a
wrapper around a function \Rfunction{disjointBins} but allows a more
flexible way to assign levels to each entry. For example, if the
arguments \Rfunarg{group.name} is specified to one of the column in
elementMetadata, the function will make sure
\begin{itemize}
\item Grouped intervals are in the same levels( if they are not
  overlapped each other).
\item No entry is following between the grouped intervals.
\item If extend.size is provided, it buffers the intervals and then
  computes the disjoint levels, thus ensuring that two closely positioned
  intervals will be assigned to different levels, a good practice for
  visualization.
\end{itemize}

For now, this function is only useful for visualization purposes.

@ 
<<addStepping-gr>>=
head(addStepping(gr))
head(addStepping(gr, group.name = "pair"))
gr.close <- GRanges(c("chr1", "chr1"), IRanges(c(10, 20), width = 9))
addStepping(gr.close)
addStepping(gr.close, extend.size = 5)
@ %def 

\subsection{Shrink the Gaps}
Sometime, in a gene centric view, we hope to truncate or shrink the
gaps to better visualize the short reads or annotation data. It's
\textbf{DANGEROUS} to shrink the gaps, since it only make sense in
visualization. And even in the visualization the x-scale will be
discontinued, and labels became somehow meaningless. \textbf{Make
  sure} you are not using the shrunk version of data when performing
the down stream analysis.

This is a tricky question too, we hope to provide a flexible way to
shrink the gaps.  When we have multiple tracks, users would be 
responsible to shrink all the tracks based on the common gaps,
otherwise there will be mis-aligned tracks.

\Rfunction{maxGap} computes a suitable estimated gap based on passed
\Robject{GenomicRanges}
@ 
<<maxGap>>=
gr.temp <- GRanges("chr1", IRanges(start = c(100, 250),
                                 end = c(200, 300)))
maxGap(gaps(gr.temp, start = min(start(gr.temp))))
maxGap(gaps(gr.temp, start = min(start(gr.temp))), ratio = 0.5)
@ %def 

\Rfunction{shrinkageFun} function will read in a
\Robject{GenomicRanges} object which represents the gaps, and returns
a function which alters a different \Robject{GenomicRanges} object, to
shrink that object based on previously specified gaps shrinking
information.  You could use this function to treat multiple
tracks(e.g. \Robject{GRanges}) to make sure they are shrunk based on
the common gaps and the same ratio.

Be careful in the following situations.
\begin{itemize}
\item When use the same shrinkage function to shrink multiple tracks,
  make sure the gaps passed to \Rfunction{shrinkageFun} function is
  the common gaps across all tracks, otherwise, it doesn't make sense
  to cut a overlapped gap within one of the tracks.
\item The default max gap is not 0, just for visualization purpose.  If
  for estimation purpose, you might want to make sure you cut all
  the gaps.
\end{itemize}

And notice, after shrinking, the x-axis labes only provide approximate
position as shown in Figure \ref{fig:shrink-single} and
\ref{fig:shrink-two}, because it's clipped. It's just for
visualization purpose.
@ 
<<shrink-single>>=
gr1 <- GRanges("chr1", IRanges(start = c(100, 300, 600),
                               end = c(200, 400, 800)))
shrink.fun1 <- shrinkageFun(gaps(gr1), max.gap = maxGap(gaps(gr1), 0.15))
shrink.fun2 <- shrinkageFun(gaps(gr1), max.gap = 0)
head(shrink.fun1(gr1))
head(shrink.fun2(gr1))
@ %def   
\begin{figure}[h!t!p!b]
  \centering
  \includegraphics[width = 0.8\textwidth]{intro-shrink-single.pdf}
\caption{Shrink single GRanges. The first track is original GRanges,
  the second one use a ratio which shrink the GRanges a little bit, and
  default is to remove all gaps shown as the third track }
  \label{fig:shrink-single}
\end{figure}


@ 
<<shrinkageFun>>=
gr2 <- GRanges("chr1", IRanges(start = c(100, 350, 550),
                               end = c(220, 500, 900)))
gaps.gr <- intersect(gaps(gr1, start = min(start(gr1))),
                     gaps(gr2, start = min(start(gr2))))
shrink.fun <- shrinkageFun(gaps.gr, max.gap = maxGap(gaps.gr))
head(shrink.fun(gr1))
head(shrink.fun(gr2))
@ %def   

\begin{figure}[h!t!p!b]
  \centering
\includegraphics[width = 0.8\textwidth]{intro-shrinkageFun.pdf}
\caption{shrinkageFun demonstration for multiple GRanges, the top two
  tracks are the original tracks, please note how we clipped common
  gaps for those two tracks and shown as bottom two tracks.}
  \label{fig:shrink-two}
\end{figure}


\subsection{GC content}
As mentioned before, GC content is an interesting variable which may
be related to various biological questions. So we need a way to
compute GC content in a certain region of a reference genome.

\Rfunction{GCcontent} function is a wrapper around \Rfunction{getSeq}
function in \Rpackage{BSgenome} package and
\Rfunction{letterFrequency} in \Rpackage{Biostrings} package. It reads
a \Robject{BSgenome} object and returns count/probability for
\textbf{GC} content in specified region.

@ 
<<gc-content, eval = FALSE>>=
library(BSgenome.Hsapiens.UCSC.hg19)
GCcontent(Hsapiens, GRanges("chr1", IRanges(1e6, 1e6 + 1000)))
GCcontent(Hsapiens, GRanges("chr1", IRanges(1e6, 1e6 + 1000)), view.width = 300)
@ %def 


\subsection{Mismatch Summary}
Compared to short-read alignment visualization, it's more useful to
just show the summary of nucleotides of short reads per base and
compare with the reference genome.  We need a way to show the
mismatched nucleotides, coverage at each position and proportion of
mismatched nucleotides, and use the default color to indicate the type
of nucleotide.

\Rfunction{pileupAsGRanges} function summarizes reads from bam files
for nucleotides on single base units in a given region, which allows
the downstream mismatch summary analysis. It's a wrapper around
\Rfunction{applyPileup} function in Rsamtools package and more
detailed control could be found under manual of PileupParam function
in Rsamtools. \Rfunction{pileupAsGRanges} function returns a GRanges
object which includes a summary of nucleotides, depth, and bam file
path. This object could be read directly into the
\Rfunction{pileupGRangesAsVariantTable} function for a mismatch
summary.

This function returns a \Robject{GRanges} object with extra
\Robject{elementMetadata}, counts for \textbf{A,C,T,G,N} and
\textbf{depth} for coverage.  \textbf{bam} indicates the bam file
path. Each row is single base unit.

\Rfunction{pileupGRangesAsVariantTable} performs comparisons to the
reference genome(a \Robject{BSgenome} object) and computes the
mismatch summary for a certain region of reads.  User need to make
sure to pass the right reference genome to this function to get the
right summary. This function drops the positions that have no reads
and only keeps the regions with coverage in the summary. The result
could be used to show stacked barchart for the mismatch summary.

This function returns a \Robject{GRanges} with the following
elementMetadata information. 

\begin{description}
\item[ref] Reference base.
\item[read] Sequenced read at that position. Each type of
  \textbf{A,C,T,G,N} summarize counts at one position, if no counts
  detected, will not show it.
\item[count] Count for each nucleotide.
\item[depth] Coverage at that position.
\item[match] A logical value, indicate it's matched or not.
\item[bam] Indicate bam file path.
\end{description}

Sample raw data is from SRA(Short Read Archive), Accession: SRR027894
and subset the gene at chr10:6118023-6137427, which within gene
RBM17. contains junction reads.

@ 
<<PileupAsGRanges, eval = FALSE>>=
library(Rsamtools)
data(genesymbol)
library(BSgenome.Hsapiens.UCSC.hg19)    
bamfile <- system.file("extdata", "SRR027894subRBM17.bam", package="biovizBase")
test <- pileupAsGRanges(bamfile, region = genesymbol["RBM17"])
test.match <- pileupGRangesAsVariantTable(test, Hsapiens)
head(test[,-7])
head(test.match[,-5])
@ %def 

% \subsection{Fragment Length Estimation}
% \emph{Fragment length} could be defined in different
% ways. Here, the \Rfunction{getFragLength} function simply uses the shrinkage
% function (introduced in previous section) to cut all gaps existing in the
% provided model and recompute the length for \Robject{GAlignments}
% object instead of using its width directly. 

% @ 
% <<getFragLength, eval = FALSE>>=
% bamfile <- system.file("extdata", "SRR027894subRBM17.bam", package="biovizBase")
% library(TxDb.Hsapiens.UCSC.hg19.knownGene)
% txdb <- Hsapiens_UCSC_hg19_knownGene_TxDb
% exons <- exonsBy(txdb, by = "tx")
% model <- subsetByOverlaps(exons, genesymbol["RBM17"])
% ## model <- exonsByOverlaps(txdb, genesymbol[16910])
% frg <- getFragLength(file, model)
% @ %def 

% \subsection{Splicing Summary}
% One of the information we could find from the RNA-seq data is the
% abundance of different alternative splicing models. There are two ways
% to visualizing the slicing summary, one is summary for full model,
% which could be represented as \Robject{GRangesList}, for instance, a
% \Robject{GRangesList} grouped by transcirpt id, and each element is
% \Robject{GRanges} object contains all the exons. Another one is single
% model which could be represented as \Robject{GRanges}, for instance, a
% \Robject{GRanges} object which just contains all the exons not grouped
% by transcript. So we need a way to compute counts support each model
% in the full model or splicing junction in the single model.

% There are different ways to summarize abundance based on RNA-seq, I
% started with a simple approach which just counting reads acrossing the
% junction. The algorithm will first filter out reads which are not
% junction reads from the raw data, then mapping junction reads to
% models.
% \begin{itemize}
% \item For full model, if one junction reads mapped to one model which
%   covers two consecutive exons, then this model plus one for
%   supporting evidence. When \Rfunarg{weighted} turned on to TRUE, if a
%   junction reads mapped to multiple model, we will simply plus 1/cases
%   for all the supported model. 
% \item For single model, we just summarize the splicing of all junction
%   reads for all the exons. Using notion like \textbf{1-2, 3-4} to
%   indicate the junction, here the number means the index of given
%   model, we assume each row in the model is one exon. When
%   \Rfunarg{model\_id} set to certain column, for example,
%   'exon\_id'. Then we use exon\_id for our notion of our summary.
% \end{itemize}

% The \Rfunction{spliceSummary} is a S4 method which dispatch on the first
% arguments, and will return a vector which is total counts for each
% model or exon junctions. And names of the vector is transcript name or
% notion like \textbf{1-3} to indicate the isoform.

% \textbf{Note:} Currently we don't support new model generation, which
% means if junction reads cannot mapped to any known model or exons
% which passed to argument \Rfunarg{model} of \Rfunction{spliceSummary}
% function, we don't give summary about these reads. But in the future,
% we would support more flexible summary for this case.

% @ 
% <<spliceSummary, eval = FALSE>>=
% splice.sum1 <- spliceSummary(bamfile, model)
% splice.sum2 <- spliceSummary(bamfile, model, weighted = FALSE)
% exonsall <- exons(txdb)
% model.single <- subsetByOverlaps(exonsall, genesymbol["RBM17"])
% splice.sum3 <- spliceSummary(bamfile, model.single)
% splice.sum4 <- spliceSummary(bamfile, model.single, model_id = "exon_id")
% @ %def 
% \begin{verbatim}
% > splice.sum1
% 38191 38192 38193 
%    57    57     0 
% > splice.sum2
% 38191 38192 38193 
%   114   114     0 
% > splice.sum3
% 1-2 1-3 
%   1 114 
% > splice.sum4
% 140875-140876 140875-140887 
%           114             1 
% \end{verbatim}

% \subsection{Aggregating from Raw Data}
% Those utilities used inside this package internally, useful
% but not exported to users until later, may be dropped or
% changed to more general existing method defined in another package, like
% package \Rpackage{stream}.

\subsection{Get an Ideogram}
\Rfunction{getIdeogram} function is a wrapper of some functionality
from \Rpackage{rtracklayer} to get certain table like cytoBand.  A
full table schema can be found
\href{http://genome.ucsc.edu/cgi-bin/hgTables}{here} at \emph{UCSC
  genome browser}. Please click \emph{describe table schema}.

This function requires a network connection and will parse the data on
the fly.  The first argument of \Rfunction{getIdeogram} is
\Rfunarg{species}.  If \Rcode{missing}, the function will give you a
choice hint, so you will not have to remember the name for the
database you want, or you can simply get the database name for a
different genome using the \Rfunction{ucscGenomes} function in
\Rpackage{Rtracklayer}. The second argument \Rfunarg{subchr} is used
to subset the result by chromosome name. The third argument cytoband
controls if you want to get the gieStain information/band information
or not, which is useful for the visualization of the whole genome or
single chromosome.  You can see some examples in \Rpackage{ggbio}.

@ 
<<ucsc-genome, eval = FALSE>>=
library(rtracklayer)
hg19IdeogramCyto <- getIdeogram("hg19", cytoband = TRUE)
hg19Ideogram <- getIdeogram("hg19", cytoband = FALSE)
unknowIdeogram <- getIdeogram()
@ %def 
\begin{verbatim}
Please specify genome 

 1: hg19      2: hg18      3: hg17      4: hg16      5: felCat4
 6: felCat3   7: galGal3   8: galGal2   9: panTro3  10: panTro2
11: panTro1  12: bosTau4  13: bosTau3  14: bosTau2  15: canFam2
16: canFam1  17: loxAfr3  18: fr2      19: fr1      20: cavPor3
21: equCab2  22: equCab1  23: petMar1  24: anoCar2  25: anoCar1
26: calJac3  27: calJac1  28: oryLat2  29: mm9      30: mm8    
31: mm7      32: monDom5  33: monDom4  34: monDom1  35: ponAbe2
36: ailMel1  37: susScr2  38: ornAna1  39: oryCun2  40: rn4    
41: rn3      42: rheMac2  43: oviAri1  44: gasAcu1  45: tetNig2
46: tetNig1  47: xenTro2  48: xenTro1  49: taeGut1  50: danRer7
51: danRer6  52: danRer5  53: danRer4  54: danRer3  55: ci2    
56: ci1      57: braFlo1  58: strPur2  59: strPur1  60: apiMel2
61: apiMel1  62: anoGam1  63: droAna2  64: droAna1  65: droEre1
66: droGri1  67: dm3      68: dm2      69: dm1      70: droMoj2
71: droMoj1  72: droPer1  73: dp3      74: dp2      75: droSec1
76: droSim1  77: droVir2  78: droVir1  79: droYak2  80: droYak1
81: caePb2   82: caePb1   83: cb3      84: cb1      85: ce6    
86: ce4      87: ce2      88: caeJap1  89: caeRem3  90: caeRem2
91: priPac1  92: aplCal1  93: sacCer2  94: sacCer1  

Selection: 
\end{verbatim}

Here is the example on how to get the genome names.
@ 
<<ucsc-genome-db, eval = FALSE>>=
head(ucscGenomes()$db)
@ %def 
\begin{verbatim}
[1] hg19    hg18    hg17    hg16    felCat4 felCat3
122 Levels: ailMel1 anoCar1 anoCar2 anoGam1 apiMel1 apiMel2 ... 
\end{verbatim}
@ 

We put the most used hg19 ideogram as our default data set, so you can
simply load it and see what they look like. They are all returned by
the \Rfunction{getIdeogram} function. The one with cytoband
information has two special columns.
\begin{description}
\item[name] Name of cytogenetic band
\item[gieStain] Giemsa stain results
\end{description}


<<default-data>>=
data(hg19IdeogramCyto)
head(hg19IdeogramCyto)
data(hg19Ideogram)
head(hg19Ideogram)
@ %def 

There are two simple functions to test if the ideogram is valid or
not.  \Rfunction{isIdeogram} simply tests if the result came from the
\Rfunction{getIdeogram} function, making sure it's a
\Robject{GenomicRanges} object with an extra
column. \Rfunction{isSimpleIdeogram} only tests if it's
\Robject{GenomicRanges} and does not require cytoband information. But
it double checks to make sure there is only one entry per
chromosome. This is useful to show stacked overview for
genomes. Please check some examples in \Rpackage{ggbio} to draw
stacked overview and single chromosome.

@ 
<<check-ideogram>>=
isIdeogram(hg19IdeogramCyto)
isIdeogram(hg19Ideogram)
isSimpleIdeogram(hg19IdeogramCyto)
isSimpleIdeogram(hg19Ideogram)
@ %def 

\subsection{Other Utilities and Data Sets} 
We are not going to introduce other utilities in this vignette, please
refer to the manual for more details, we have other function to
transform a \Robject{GRanges} to a special format only for graphic
purpose, such as function \Rfunction{transformGRangesForEvenSpace} and
\Rfunction{transformGRangesToDfWithTicks} could be used for grand
linear view or linked view as introduced in package \Rpackage{ggbio}.

We have introduced data sets like \Robject{hg19IdeogramCyto} and
\Robject{hg19Ideogram} in the previous sections. We also have a data
set called \Robject{genesymbol}, which is extracted from human
annotation package and stored as \Robject{GRanges} object, with extra
columns \emph{symbol} and \emph{ensembl\_id}. For fast mapping, we use
\emph{symbol} as row names too.

This could be used for convenient overlapped subset with other
annotation, and has potential use in a auto-complement drop list for
gene search bar like most gene browsers have.

@ 
<<genesymbol>>=
data(genesymbol)
head(genesymbol)
genesymbol["RBM17"]

@ %def 
\section{Bugs Report and Features Request}

Latest code are available on github
\url{https://github.com/tengfei/biovizBase}

Please file bug/request on issue page, this is preferred way. or
email me at yintengfei <at> gmail dot com.

It's a new package and under active development.

Thanks in advance for any feedback.
\section{Acknowledgement}
I wish to thank all those who helped me. Without them, I could not
have started this project.
\begin{description}
\item[Genentech]{Sponsorship and valuable feed back and help for this
    project and my other project.}
  \item[Jennifer Chang]{Feedback on this package}
\end{description}


\section{Session Information}
@ 
<<R-session>>=
sessionInfo()
@ %def 
\end{document}