Clementine Lunar Image Browser Information
The Clementine Lunar Image Browser (CLIB) is an effort in progress at the Naval Research Laboratory's (NRL) Center for Computational Science (CCS). The main objective is to provide the scientific community and the public with access to all 1.8 million images recorded by the Deep Space Program Science Experiment, Clementine. Uncompressed this data totals somewhere in the neighborhood of 400,000,000,000 bytes of information.
- Version 1.5 is a significant step in the user interface. Sections of a 58 megabyte image created from Clementine data are returned to the user at multiple resolutions, multiple sizes and centered on whatever part of the Moon the user wishes. Consequently users can zoom in to a location of interest. This multi-resolution feature is implemented using a wavelet compression technology, known as MrSID, developed at Los Alamos National Laboratory as part of the Sunrise Project.
Version 1.5 uses the final PDS data set as opposed to the "raw" data set that had been used by version 1.1. This will eventually allow users to easily obtain PDS versions of the data they are viewing.
- The first version of the Clementine Lunar Image Browser has received a small upgrade to bring it to version 1.1. Image retrievals will often be performed in half the time that was previously required. Although quite limited in scope in comparison with the plan for the final version it is a significant step forward.
- Due to the size of the data set and our strategy for storing such a large amount of data, there are a number of steps that occur between your request for an image and the display of that image. Once an image has been obtained the data associated with it is displayed in a form below it. You may alter one or more of those variables to select a new image. Alternatively you may click on one of the eight arrow buttons above the form to view an image that is adjacent to the current image.
- First and foremost the Clementine Lunar Image Browser must determine which file is associated with the parameters you, the user, have indicated. You may find that, on rare occasions some parameters do not yield a filename. Version 1.5 searches for an image with the same sensor/filter combination that is geographically close to the image you requested. Every effort is being made to reduce the frequency of this event.
- The Clementine data is primarily stored as groups of approximately 200 images in tar files on D2 small tapes in an E-mass data tower. As files are requested they are moved from tape to disk. This process takes under a minute. There are however only two tape drives to facilitate the transfers so a specific transfer could take much longer if there are a number of transfers in the queue in front of it. If the image you request is on tape you will be given an intermediate page that informs you of this process as well as lists some information about the selected image.
- If the image you have requested has been requested by someone else recently it may already reside on disk. In this case you will receive the image page immediately and skip the intermediate page. Even though it is already on disk the display of the image does take a number of seconds. After being transferred to disk the file you requested still has to be extracted from the tar file in which it is located after which it must be converted from its native format (PDS) to one that is WWW compatible (GIF).
- In the spirit of the Clementine satellite, the Clementine Lunar Image Browser will become better and faster. (it's already really cheap...free to you!)
- Faster - Although there are some fixed constraints with regard to time, like retrieving files from tape, there are other areas where we expect to decrease the time that CLIB requires in version 2.
- Expanded - More sensor/filter combinations will be added to the CLIB. Another group is creating the databases that allow us to determine which files go with a specific Lat/Long. As soon as they are available we'll plug them in the the CLIB!
- File Transfer of GIFs - Now that there are a WWW browsers that allow users to save in-line images it is not likely that we will make a "send only the gif" option to any of the tools.
- Queue Information - In version 2 we had planned to give information about a file requests position in the queue when retrieving a file from tape. The hope is that this would aid users in their understanding of the retrieval process. We have yet to notice any queues longer than a couple of requests. That put together with the fact that we are moving the data set to a tape tower with four tape drives leads us to believe that a queue monitoring functionality would not be the best way to invest our time.
- Search by Range - We hope to add the ability of retrieving all the images that fall between two or more locations. This ability could seriously stress the server if misused so we are approaching it cautiously.
- Search by Feature - This will allow users to retrieve an image associated with a particular lunar feature.
- Browse Level Viewing - This objective was announced with the release of version 1 and has been achieved with version 1.5. Users are now able to zoom in to and out of a variety of resolutions.
- PDS support - Eventually the CLIB will support the transfer of the files from which the GIFs are derived. The Clementine data is stored in a NASA standard file type known as Planetary Data Systems (PDS). These files have headers that contain detailed information about that specific image.
- Please note these plans are not set in stone nor is this list considered complete. As development on the Clementine Lunar Image Browser continues the plans for improving CLIB will undoubtedly change.
Behind the Pixels
- The Clementine Lunar Image Browser would not be at the stage it is now if it weren't for the contributions of a number of people, only some of which are mentioned here. Stephen Roberson is the primary developer of the CLIB and the NRL-Clementine WWW presence. He is happy to receive feedback about the project as well as gifts in any denomination. Seriously, he would be quite interested in information with regards to who is using the CLIB and for what purposes. Many other members of the CCS at NRL have aided and will continue to aid (hopefully) in the project. They include but are not limited to Bill Fenner, Glenn Heinle, Heidi Hornstein, Ken Hornstein, and Seth Shevach.
- Applied Coherent Technology Corporation (ACT), which is handling some image processing of the Clementine data, has aided the CLIB effort immensely. Howard Taylor has been the main liaison between ACT and NRL with regard to the CLIB.
- The technology allowing the multi-resolution interface in CLIB was developed by Calvin Hamilton and Jonathan Bradley of Los Alamos National Laboratory (LANL) under the Sunrise Project.
- Some images were also acquired through the efforts of United States Geological Survey at Flagstaff, AZ.
- More information about the Clementine Lunar Image Browser is available on the CLIB Help page and the CLIB Frequently Asked Questions page. Information about the Deep Space Program Science Experiment, Clementine is available. You are also encouraged to send mail to email@example.com with your questions and comments.
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