Montage Image Mosaic Software

Montage Image Mosaic Software Engine

Mosaic image of the Pleiades star cluster created with Montage. The blue, green, and red channels of this three- color image were made from B-, R-, and I-band images, respectively, from the Digitized Sky Survey (DSS). Image credit: Inseok Song (University of Georgia)
Developer(s)	IPAC, JPL, CACR, ISI
Initial release	October 10, 2003
Stable release	3.3 / 15 December 2010; 9 months ago (2010-12-15)
Written in	ANSI-compliant C
Operating system	Linux, Unix, Mac OS X
Platform	desktop, cluster, supercomputer and cloud computing environments
Size	300 MB for installation, plus additional disk space for storing input and output images
Type	Astronomy software
License	Non-exclusive and non-commercial open source license issued by Caltech and JPL
Website	montage.ipac.caltech.edu Online Web Service

Montage (full name Montage Astronomical Image Mosaic Engine) is a software toolkit used in astronomy to assemble astronomical images in Flexible Image Transport System (FITS) format into composite images, called mosaics, that preserve the calibration and positional fidelity of the original input images. It won a NASA Space Act Award in 2006. The software is described in detail by Jacob et al (2009)^[1].

Montage was developed to support scientific research. It enables astronomers to create images of regions of the sky that are too large to be be produced by astronomical cameras. It also creates composite images of a region of the sky that has been measured with different wavelengths and with different instruments; the composite appears as if the area was measured with the same instrument on the same telescope.

Features

Montage performs the following steps to compute a mosaic according to the user’s specifications, as follows:

1. Discover the geometry of the input images on the sky from the attributes recorded in the input FITS and use it to calculate the geometry of the output mosaic on the sky. These input images and the output mosaic are two-dimensional representations of regions of the three-dimensional curved surface of the sky. By analogy with terrestrial cartography, a mathematical projection describes the relationship between the pixel coordinates in the image and the pixels on three-dimensional surface of the sky. As in cartography, there are many projections in use in astronomy, which formally described them in the World Coordinate System (WCS. Montage supports all projections in the WCS.
2. Re-project the input images to the required spatial scale, coordinate system, image projection, and image rotation of the output mosaic.
3. Model the background radiation in the input images to achieve common flux scales and background levels across the mosaics.
4. Co-add the re-projected, background-corrected images into a mosaic.

Applications

Montage is used primarily in scientific research and in the creation of scientific products. Recent examples include:

• Stock and Barlow (2010)^[2] used it to search for ejecta from WR-stars by creating mosaics of images from the AAO/UKST Southern Hα Survey (SHS).

• Aguirre et al. (2010)^[3] used Montage to re-project images to create an atlas of images for the Bolocam Galactic Plane Survey (BGPS), a millimeter-wave continuum survey of the Galactic plane.

• Anderson et al. (2010)^[4] used it to re-sample 350 μm maps of data from the Herschel Space Telescope in their study of the physical properties of the dust of the HII region RCW 120.

• The Arecibo Legacy Fast ALFA survey (ALFALFA) (Giovanelli et al. 2005)^[5] used Montage to create a large wide-field mosaic of neutral hydrogen emission at 21 cm.

Fig. 1: 1,500-square-degree-equal area Aitoff projection mosaic, computed with Montage, of galactic neutral hydrogen observed with the ALFALFA survey near the North Galactic Pole (NGP). Image courtesy of Dr. Brian Kent and the ALFALFA collaboration.

Montage is also widely used in developing the infrastructure of the next generation of data-aware computing and cyber-infrastructure, including:

• Designing fault-tolerant task scheduling in distributed environments
• Exploring issues of data provenance in scientific workflows
• Exploring the cost and performance of scientific applications running on clouds
• Developing application performance frameworks

Design and Performance

Montage was developed as a toolkit written in American National Standards (ANSI)–compliant C for performance and portability. The toolkit contains software components that perform the steps needed to compute a mosaic. Montage operates as a workflow application, where each component creates an output file that becomes the input to a subsequent component. Figure 2 shows how these components operate together to produce a mosaic. The toolkit design offers flexibility to users. They may, for example, use Montage as a re-projection tool, or deploy a custom background rectification algorithm while taking advantage of the re-projection and co-addition engines.

Fig. 2: The processing flow in the Montage mosaic engine, illustrated for a mosaic made of three images. The boxes contain names of components available in the Montage distribution.

Montage runs on the command line under all common Unix and Linux platforms, and the same code runs on desktop, cluster and super-computer environments. It is highly parallelizable and has been run through all common workflow parallelization techniques. On a cluster of 128 2.3-GHz processors running Red Hat Linux, it can process 40 million pixels in 32 minutes.

Licensing and Distribution

Montage is freely available for download and use through a non-exclusive, non-commercial license agreement issued by the California Institute of Technology and the Jet Propulsion Laboratory from the Montage Web site. The software code, documentation and sample files are considered open source software. New versions are released periodically to correct defects and include enhanced functionality. The latest release is version 3.3 (December, 2010).

The distribution includes software components for creating mosaics, ancillary modules for managing and manipulating images, all third-party libraries, and modules for running Montage in parallel on clusters, supercomputers, clouds and grid through the Pegasus workflow management tool and the Message Passing Interface (MPI).

System Requirements

Montage is built with a simple make script on all common Unix and Linux platforms. It requires 300 MB of disk space for installation. The amount of memory and disk space needed for processing depends on the size of the input and output images, which is calculated using a formula described on the software's Disk Space System Requirements page. Montage does not operate on Microsoft Windows platforms, but has been run on Linux emulators running under Windows.

Web Service

In addition to the software toolkit, an online Image Mosaic Service uses Montage to generate image mosaics requested on a simple web form. It offers images from three important wide-area data sets:

• The Two-Micron All Sky Survey (2MASS), a survey of the entire sky in three Near-Infrared bands.
• The Sloan Digital Sky Survey (SDSS), which maps one-quarter of the sky in the blue, visible and red.
• The Digitized Sky Surveys (DSS) from the Space Telescope Science Institute (STScI), which cover the whole sky in the blue, visible, and red.

The service uses Virtual Observatory (VO) protocols to access the images. There are plans to extend the service to include more data sets and to offer larger and multi-color mosaics.

Support

Montage maintains a dedicated help desk, which can be contacted through a Web form .

Community Contributions to Montage

Members of the Montage user community have contributed scripts that enhance or extend Montage’s functionality, including:

A Python wrapper developed by Thomas Robitaille at the Harvard-Smithsonian Center for Astrophysics automates some of the manual Montage functions and facilitates mosaicking and re-projecting.

A BASH script developed by Inseok Song at the University of Georgia creates a mosaic of the Pleiades star cluster from online Digitized Sky Survey (DSS) data.

A set of C-shell scripts contributed by Dr. Colin Aspin create full-color mosaics of regions of the sky using images from 2MASS, DSS and SDSS.

Credits

Montage was developed at the Infrared Processing and Analysis Center (IPAC), California Institute of Technology, the Jet Propulsion Laboratory and the Center for Advanced Computer Research, California Institute of Technology, in collaboration with the Information Sciences Institute, University of Southern California.

Montage is maintained at the Infrared Processing and Analysis Center, with support from the Information Sciences Institute at the University of Southern California and the Computational Institute at the University of Chicago.

Acknowledgment

Montage was funded by the National Aeronautics and Space Administration's Earth Science Technology Office, Computational Technologies Project, under Cooperative Agreement Number NCC5-626 between NASA and the California Institute of Technology. The Web-based Image Mosaic Service uses software developed by IPAC for the U.S. National Virtual Observatory, which is sponsored by the National Science Foundation.

References

1. ^ Jacob, J. C., Katz, D. S.; Berriman, G. B; Good, J. C.; Laity, A. C.; Deelman, E.; Kesselman, C.; Sing, G; Su, M.-H.; Prince, T. A.; and Williams, R. 2009. "Montage: A Grid Portal and Software Toolkit for Science-Grade Astronomical Image Mosaicking." International Journal of Computational Science and Engineering 4(2):73-87
2. ^ Stock, D. J.; and M. J. Barlow. 2010. "A search for Ejecta Nebulae around Wolf-Rayet Stars using the SHS Ha survey," accepted for publication in Monthly Notices of the Royal Astronomical Society
3. ^ Aguirre, J. E.; Ginsburg,A. G; Dunham,M. K.; Drosback,M.M.; Bally, J.; Battersby, C.; Bradley, E.T; Cyganowski,C.; Dowell, D. ; Evans N. J. II; Glenn, J.; Harvey, P.; Rosolowsky,E. ; Stringfellow, G. S.; Walawender, J.; Williams, J. P. 2010, "The Bolocam Galactic Plane Survey: Survey Description and Data Reduction," accepted for publication in The Astrophysical Journal Supplement
4. ^ Anderson, L. D., A. Zavagno, J.A. Rodon, D. Russeil, A. Abergel, P. Ade, P. Andre, H. Arab, J.-P. Baluteau, J.-P. Bernard, K. Blagrave, F. Boulanger, M. Cohen, M. Compiegne, P. Cox, E. Dartois, G. Davis, R. Emery, T. Fulton, C. Gry, E. Habart, M. Huang, C. Joblin, S.C. Jones, J. Kirk, G. Lagache, T. Lim, S. Madden, G. Makiwa, P. Martin,M.-A.Miville-Deschenes, S.Molinari, H.Moseley, F.Motte, D.A. Naylor, K. Okumura, D. Pinheiro Gocalvez, E. Polehampton, P. Saraceno, S. Sidher, L. Spencer, B. Swinyard, D. Ward-Thompson, G.J. White 2010. "The physical properties of the dust in the RCW 120 HII region as seen by Herschel," accepted for publication in Astronomy & Astrophysics
5. ^ Giovanelli, R., Haynes, M.P., Kent, B.R., and 37 coauthors. 2005, "ALFALFA: I. Science Goals, Survey Design and Strategy," The Astrophysical Journal, 130, 2598

External links

• Montage Web site
• Montage Web Service
• U.S. Virtual Astronomical Observatory
• Better Ways to Make Large Mosaics? Astrobetter blog post and discussion about Montage pros and cons
• Pegasus Workflow Management System Web site
• Montage A Rising Star in Grid-Enabled Sky Mosaics Feature article in International Science Grid This Week
• Pegasus invites new communities to saddle up Feature article in International Science Grid This Week
• Cloud Computing in the Age of Data-Intensive Science Feature article on SPIE Web site
• NASA Space Act Award page
• Infrared Processing and Analysis Center