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Cardinal (version 1.4.0)

iSet-class: Class to Contain High-Throughput Imaging Experiment Data and Metadata

Description

A container class for data from high-throughput imaging experiments and associated metadata. Classes derived from from iSet contain one or more arrays or array-like objects with an equal number of dimensions as imageData elements. It is assumed that the first dimension of each such element corresponds to the data features, and all other dimensions are described by associated coordinates in the pixelData slot. Otherwise, derived classes are responsible for managing how the elements of imageData behave and their relationship with the rows of pixelData and featureData.

The MSImageSet class for mass spectrometry imaging experiments is the primary derived class of iSet. Its parent class SImageSet is another derived class for more general images.

This class is based on the eSet virtual class from Biobase. However, the iSet class contains an imageData slot which is an 'immutableEnvironment' that preserves copy-on-write behavior for iSet derived classes, but only copying elements of imageData when that slot specifically is modified. In addition pixelData is an IAnnotatedDataFrame that stores pixel information such as pixel coordinates in addition to phenotypic data.

Arguments

Slots

imageData:
An instance of ImageData, which stores one or more array or array-like objects of equal number of dimensions as elements in an 'immutableEnvironment'. This slot preserves copy-on-write behavior when it is modified specifically, but is pass-by-reference otherwise, for memory efficiency.
pixelData:
Contains pixel information in an IAnnotatedDataFrame. This includes both pixel coordinates and phenotypic and sample data. Its rows correspond to individual pixels, many of which may belong to the same sample. Apart a requirement on columns describing the pixel coordinates, it is left to derived classes to decide the relationship to elements of imageData.
featureData:
Contains variables describing features. It Is left to derived classes to decide the relationship to elements of imageData.
experimentData:
Contains details of experimental methods. Should be an object of a derived class of MIAxE.
protocolData:
Contains variables describing the generation of the samples in pixelData.
.__classVersion__:
A Versions object describing the version of the class used to created the instance. Intended for developer use.

Extends

VersionedBiobase, directly. Versioned, by class "VersionedBiobase", distance 2.

Creating Objects

iSet is a virtual class. No instances can be created.

Methods

Class-specific methods:
sampleNames(object), sampleNames(object) <- value:
Access and set the sample names in the pixelData and protocolData slots.
featureNames(object), featureNames(object) <- value:
Access and set the feature names in the featureData slot.
pixelNames(object), pixelNames(object) <- value:
Access and set the pixel names in the pixelData slot.
coordLabels(object), coordLabels(object) <- value:
Access and set the coordinate names described by the coordinate variables in the pixelData slot. Note that this does not set or get coordinate names with a labelType of sample, regardless of whether they are currently being used to describe coordinates or not. Therefore, checking coordLabels(object) versus names(coord(object)) is a simple way of checking whether a dataset is 2D or 3D.
coord(object), coord(object)<-:
Return or set the coodinates. This is a data.frame containing the subset of columns of data for which the variables have a 'labelType' of 'dim'.
imageData(object), imageData(object) <- value:
Access and set the imageData slot.
pixelData(object), pixelData(object) <- value:
Access and set the pixelData slot.
pData(object), pData(object) <- value:
Access and set the pixel information.
varMetadata(object), varMetadata(object) <- value:
Access and set the metadata describing the variables in pData.
varLabels(object), varLabels(object) <- value:
Access and set the variable labels in pixelData.
featureData(object), featureData(object) <- value:
Access and set the featureData slot.
fData(object), fData(object) <- value:
Access and set the feature information.
fvarMetadata(object), fvarMetadata(object) <- value:
Access and set the metadata describing the features in fData.
fvarLabels(object), fvarLabels(object) <- value:
Access and set the feature labels in featureData.
features(object, ...):
Access the feature indices (rows in featureData) corresponding to variables in featureData.
pixels(object, ...):
Access the pixel indices (rows in pixelData) corresponding to variables in pixelData.
experimentData(object), experimentData(object) <-:
Access and set the experimentData slot.
protocolData(object), protocolData(object) <-:
Access and set the protocolData slot.
storageMode(object), storageMode(object)<-:
Return or set the storage mode of the imageData slot. See documentation on the storageMode slot above for more details.
Standard generic methods:
initialize:
Initialize a object of an iSet derived class. Called by new. Not to be used by the user.
validObject:
Checks that there exist columns in pixelData describing the pixel coordinates, cooresponding to the dimensions of the elements of imageData. For every named dimension of the arrays on imageData there must be a pData column describing its pixel coordinates. Also checks that the sampleNames match between pixelData and protocolData.
combine(x, y, ...):
Combine two or more iSet objects. To be combined, iSets must have identical featureData and distinct pixelNames and sampleNames. All elements of imageData must have matching names. Elements of imageData are combined by calls for combine.
dim:
The dimensions of the object, as determined by the number of features (rows in featureData) and the number of pixels (rows in pixelData). This may differ from the dimensions returned by dims(object) (which corresponds to the arrays in data) or returned by dim(imageData(object)). See SImageSet for an example where this is the case, due to its use of a "virtual" datacube.
dims:
A matrix with each column corresponding to the dimensions of an element in the data slot.
iSet$name, iSet$name <- value:
Access and set the name column in pixelData.
iSet[[i, ...]], iSet[[i, ...]] <- value:
Access and set the column i (character or numeric index) in pixelData. The ... argument can include named variables (especially 'labelDescription') to be added to the varMetadata.

See Also

eSet, SImageSet, MSImageSet

Examples

Run this code
## Cannot create an iSet object
try(new("iSet"))

## Create an iSet derived class
MyImageSet <- setClass("MyImageSet", contains="iSet")
MyImageSet()

removeClass("MyImageSet")

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