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Package Overview

Likes its predecessor, Horizon 2.0 is made up of a collection of subpackages as well as a few third-party packages. This pages gives a brief description of the contents these packages. This document will be updated as the various Horizon components are released.

You can download those packages that are currently available (individually or all together) via the...

Horizon 2.0 Release Page

Just looking for API documentation? Browse currently available APIs via the...

Horizon 2.0alpha3 API Index

The above APIs will in general include classes and packages not yet released.

Demonstration Applets

Check out these example applets that use Horizon to browse image data:

a simple browser: this demonstrates the use of the Horizon data model.
a Java figure: this applet shows how Java and Horizon can be used to support a dynamic figure that is part of an electronic document.

Horizon subpackages

The following table describes the subpackages that make up the Horizon package, ncsa.horizon. Some of the subpackages can be used independently without the rest of the package, while others make use of package interdependency; the "Depends On" column indicates any dependencies. Links under the "Package" column lead to more information about the package. All alpha release dates are approximate.

Package Description Available Depends on Analogs in v1.3

ncsa.horizon.util general purpose utility classes that include metadata containers, classes for selecting regions of data, a UNIX-like command line parser, a flexible numeric formatter supporting scientific notation, and more. Now nothing ncsa.horizon.util

ncsa.horizon.arrayND classes that provide fast, flexible access to multi-dimensional arrays. They support a variety of storage schemes and include an efficient scheme for iterating through the elements. Now nothing n/a

ncsa.horizon.util.arrayND some helper classes that allow the data selection classes with the multi-dimensional array classes. Now nothing n/a

ncsa.horizon.coordinates supports complex conversions between locations in data space and (multiple) world coordinate systems. In particular, it can support a large variety of spherical coordinate systems (via the FITSWCS package). Formatting of positions are by default completely encapsulated. Now ncsa.horizon.util,
FITSWCS ncsa.horizon.coordinates

ncsa.horizon.model classes that handle reading, accessing, and creating images from the basic data. Format-specific classes are found subpackages of ncsa.horizon.model (e.g. classes specific to the FITS format are found in the ncsa.horizon.model.fits package). Now ncsa.horizon.util,
ncsa.horizon.arrayND,
ncsa.horizon.util.arrayND,
ncsa.horizon.coordinates,
ncsa.horizon.system ncsa.horizon.viewable,
ncsa.horizon.data

ncsa.horizon.system supports various Horizon environment-wide services. The most important are those that automate access to data (i.e. the creation of Viewable objects) in a format-independent way. Now ncsa.horizon.util,
ncsa.horizon.model n/a

ncsa.horizon.awt small general-purpose, non-Horizon-specific components and graphics helper classes Now nothing ncsa.horizon.awt

ncsa.horizon.awt.image General purpose image filters Now nothing ncsa.horizon.awt.image

ncsa.horizon.awt.color ColorModels and related classes that support the Horizon convention for mapping a color table to data. Now The following classes from ncsa.horizon.awt:
Marker, MarkerChain, PanelButton, SimpleImageCanvas, & SimpleFrame ncsa.horizon.awt.image

ncsa.horizon.viewer GUI components and related classes that display visualizations of the data. Now ncsa.horizon.model,
ncsa.horizon.util,
ncsa.horizon.coordinates,
ncsa.horizon.awt,
ncsa.horizon.awt.color,
ncsa.horizon.gui ncsa.horizon.viewer

ncsa.horizon.gui non-viewer GUI components that display information and/or control a viewer. Now ncsa.horizon.model,
ncsa.horizon.util,
ncsa.horizon.coordinates,
ncsa.horizon.awt,
ncsa.horizon.awt.color,
ncsa.horizon.viewer ncsa.horizon.modules

ncsa.horizon.collab Support for collaboration Now ncsa.horizon.system,
ncsa.horizon.util,
ncsa.horizon.model,
ncsa.horizon.awt n/a

Package	Description	Available	Depends on	Analogs in v1.3
ncsa.horizon.util	general purpose utility classes that include metadata containers, classes for selecting regions of data, a UNIX-like command line parser, a flexible numeric formatter supporting scientific notation, and more.	Now	nothing	ncsa.horizon.util
ncsa.horizon.arrayND	classes that provide fast, flexible access to multi-dimensional arrays. They support a variety of storage schemes and include an efficient scheme for iterating through the elements.	Now	nothing	n/a
ncsa.horizon.util.arrayND	some helper classes that allow the data selection classes with the multi-dimensional array classes.	Now	nothing	n/a
ncsa.horizon.coordinates	supports complex conversions between locations in data space and (multiple) world coordinate systems. In particular, it can support a large variety of spherical coordinate systems (via the FITSWCS package). Formatting of positions are by default completely encapsulated.	Now	ncsa.horizon.util, FITSWCS	ncsa.horizon.coordinates
ncsa.horizon.model	classes that handle reading, accessing, and creating images from the basic data. Format-specific classes are found subpackages of `ncsa.horizon.model` (e.g. classes specific to the FITS format are found in the `ncsa.horizon.model.fits` package).	Now	ncsa.horizon.util, ncsa.horizon.arrayND, ncsa.horizon.util.arrayND, ncsa.horizon.coordinates, ncsa.horizon.system	ncsa.horizon.viewable, ncsa.horizon.data
ncsa.horizon.system	supports various Horizon environment-wide services. The most important are those that automate access to data (i.e. the creation of `Viewable` objects) in a format-independent way.	Now	ncsa.horizon.util, ncsa.horizon.model	n/a
ncsa.horizon.awt	small general-purpose, non-Horizon-specific components and graphics helper classes	Now	nothing	ncsa.horizon.awt
ncsa.horizon.awt.image	General purpose image filters	Now	nothing	ncsa.horizon.awt.image
ncsa.horizon.awt.color	ColorModels and related classes that support the Horizon convention for mapping a color table to data.	Now	The following classes from ncsa.horizon.awt: Marker, MarkerChain, PanelButton, SimpleImageCanvas, & SimpleFrame	ncsa.horizon.awt.image
ncsa.horizon.viewer	GUI components and related classes that display visualizations of the data.	Now	ncsa.horizon.model, ncsa.horizon.util, ncsa.horizon.coordinates, ncsa.horizon.awt, ncsa.horizon.awt.color, ncsa.horizon.gui	ncsa.horizon.viewer
ncsa.horizon.gui	non-viewer GUI components that display information and/or control a viewer.	Now	ncsa.horizon.model, ncsa.horizon.util, ncsa.horizon.coordinates, ncsa.horizon.awt, ncsa.horizon.awt.color, ncsa.horizon.viewer	ncsa.horizon.modules
ncsa.horizon.collab	Support for collaboration	Now	ncsa.horizon.system, ncsa.horizon.util, ncsa.horizon.model, ncsa.horizon.awt	n/a

Imported Packages

Among the outside packages Horizon imports, two are of particular interest for astronomical applications:

nom.tam.fits: a FITS reader

Horizon 2.0 ships with the Java FITS reader by Tom McGlynn which is comprised of nom.tam.fits, nom.tam.data, and nom.tam.util. Each of these can be downloaded as seperate ZIP files from his site. API documentation is also availabe there.

FITSWCS 2.4

This package is a Java port of the WCSLIB C library by Mark Calabretta. This library implements the FITS World Coordinate Systems convention, providing position transformations between a spherical surface and its projection onto a map plane. The translation of this library was carried out to support the generalized coordinate classes in ncsa.horizon.coordinates; however, they can easily be used independently of the Horizon package. This package is available as a gzip-ed tar file:

FITSWCS-2.4.tar.gz (198 kB)

This Java package may also be obtained as part of the WCSLIB distribution (Ver 2.4) by Mark Calabretta which also contains versions implemented in C and FORTRAN. This distribution can be obtained from:

Australia: ftp://ftp.atnf.csiro.au/pub/software/wcslib/
USA (mirror): http://fits.cv.nrao.edu/src/wcs/

For a more detailed description of the FITSWCS java package, refer to the distribution README file as well as the FITSWCS API. For more information on FITS World Coordinate System (WCS) convention, refer to the paper "Representations of Celestial Coordinates in FITS" by Greisen and Calabretta.