LatticeAsContour.h

Classes

LatticeAsContour -- Class to manage the drawing of contour maps of slices from AIPS++ Lattices (full description)

template <class T> class LatticeAsContour : public LatticePADisplayData<T>

Interface

Public Members

LatticeAsContour(Array<T> *array, const uInt xAxis, const uInt yAxis, const uInt mAxis, const IPosition fixedPos)

LatticeAsContour(Array<T> *array, const uInt xAxis, const uInt yAxis)

LatticeAsContour(ImageInterface<T> *image, const uInt xAxis, const uInt yAxis, const uInt mAxis, const T fixedPos)

LatticeAsContour(ImageInterface<T> *image, const uInt xAxis, const uInt yAxis)

virtual ~LatticeAsContour()

virtual void setupElements()

virtual void setDefaultOptions()

virtual Bool setOptions(Record &rec, Record &recOut)

virtual Record getOptions()

virtual Display::DisplayDataType classType()

virtual String className()

Description

Review Status

Date Reviewed:: yyyy/mm/dd

Prerequisite

Etymology

The purpose of this class is to draw "contour" maps of data that is "lattice"-based.

Synopsis

This class should be used to display contour maps---ie. line drawings connecting data points of equal intensity (or level)---of two-dimensional slices of data extracted from AIPS++ Lattices or Arrays having two or more dimensions. Thus, this is the class to use to display standard zeroth-order moment map contour overlays for use on Digitized Sky Survey images, for example.

At construction, any axes in the data can be mapped to the X and Y axes of the display device (see the PrincipalAxesDD class). For data with more than two dimensions, a third axis in the dataset can be selected for generating a sequence of maps along: this is known as the "movie" axis. Animation (see the Animator class) will cause different slices of the data to be selected from along this axis. After construction, the axis settings of a LatticeAsContour object can be modified at a later stage.

The LatticeAsContour object supports a number of options which can be set or retrieved using the setOptions and getOptions functions. These functions simply accept a Record, which can be converted from a GlishRecord: this is done in the GTkDisplayData class. The options for the LatticeAsContour class are:

levels: a Vector (or Vector) of one or more elements, being the data values at which the contours are drawn. Depending on type, the values in the vector are interpreted as absolute or fractions between the data minimum and maximum.

type: a String, one of "frac" or "abs", indicating whether the contour values in "levels" (multiplied by "scale") are fractions of the data range between the minimum and maximum, or are instead absolute contour levels in the native units of the data.

scale: a Float or Double which provides an additional scale factor to apply to the contour levels in "levels."

line: a positive Integer specifying the line width of contours.

dashneg: a Boolean value, which if True, will force contours at negative data values to be drawn in dashed line style.

dashpos: a Boolean value, which if True, will force contours at positive data values to be drawn in dashed line style.

color: a String which is the color with which to draw the contours. A valid X Color is required.

Example

A LatticeAsContour object could be constructed and used as follows:

    PagedImage<Float> *pimage = new PagedImage<Float>(String("test.im"));
    DisplayData *dd;
    uInt ndim = pimage->ndim();
    if (ndim < 2) {
      throw(AipsError(String("Image has less than two dimensions")));
    } else if (ndim == 2) {
      dd = (DisplayData *)(new LatticeAsContour<Float>(pimage, 0, 1));
    } else {
      IPosition fixedPos(ndim);
      fixedPos = 0;
      dd = (DisplayData *)(new LatticeAsContour<Float>(pimage, 0, 1, 2,
                                                      fixedPos));
    }
    // wcHolder is an existing WorldCanvasHolder *...
    wcHolder->addDisplayData(ddata);
    wcHolder->refresh();

Motivation

Displaying 2-dimensional slices of a lattice-based data volume is a standard display requirement for astronomical data visualization and presentation.

Template Type Argument Requirements (T)

Thrown Exceptions

To Do

Member Description

LatticeAsContour(Array<T> array, const uInt xAxis, const uInt yAxis, const uInt mAxis, const IPosition fixedPos)
LatticeAsContour(Array<T> array, const uInt xAxis, const uInt yAxis)

Array-based constructors: >2d and 2d. xAxis and yAxis specify which axis in the array (0-based) should be mapped to X and Y on the display device: ie. 2-d slices of the data to be displayed have these axes. mAxis specifies the "movie" axis, which is the axis along which different slices are taken. fixedPos is an IPosition having the same length as the number of dimensions in the array, and indicate the fixed axis values for axes in the data that are not specified as xAxis, yAxis or mAxis.

LatticeAsContour(ImageInterface<T> image, const uInt xAxis, const uInt yAxis, const uInt mAxis, const T fixedPos)
LatticeAsContour(ImageInterface<T> image, const uInt xAxis, const uInt yAxis)

Image-based constructors: >2d and 2d. xAxis and yAxis specify which axis in the image (0-based) should be mapped to X and Y on the display device: ie. 2-d slices of the data to be displayed have these axes. mAxis specifies the "movie" axis, which is the axis along which different slices are taken. fixedPos is an IPosition having the same length as the number of dimensions in the image, and indicate the fixed axis values for axes in the data that are not specified as xAxis, yAxis or mAxis.

virtual ~LatticeAsContour()

Destructor

virtual void setupElements()

Create the various elements in the sequence of displayable maps. This is called upon construction as well as whenever the display and/or movie axes are changed via a call to PrincipalAxesDD::setAxes. virtual void setupElements(IPosition fixedPos = IPosition(2));

virtual void setDefaultOptions()

install the default options for display

virtual Bool setOptions(Record &rec, Record &recOut)

Apply the options stored in the provided Record to the LatticeAsContour object. If the return value is True, then some options have changed, and a refresh is needed to update the display.

virtual Record getOptions()

Retrieve the currently set options, and their types, default values, and any help text associated with each parameter. This information can be used to generate form-type graphical user interfaces or command-line interfaces to set the options with prompts.

virtual Display::DisplayDataType classType()

Return the DisplayData type; used by the WorldCanvasHolder to determine the order of drawing.

virtual String className()

class name