The Sidescan Sonar Field Data
The Navigation Data
The GLORIA sidescan sonar data files (identified as NetCDF and RAW on the data index pages) are binary encoded and cannot be viewed directly. The imagery must be downloaded from the CD to a local disk for processing and analysis. To assist in locating and downloading the desired data, the archived files are cross referenced on four available index files - a separate index for each of the four cruises archived here. The index files were created to assist in selecting the GLORIA imagery and associated header information and retrieving them to a client workstation.
In addition to the GLORIA imagery files, there is an ASCII header file which contains the date, time, position and depth information for each scan line contained in the associated RAW image file. This information is needed if processing of the imagery will be done. This header information is stored internally in the NetCDF file but is stored externally for the RAW files. The header files are accessible by clicking the checkmark alongside the hyper-text links to the GLORIA imagery.
To download a selected image file using NCSA's Mosaic, the user may follow these steps. The steps required to download a data file utilizing a different WWW client may differ slightly. See the notes below if downloading a data file with Netscape ©.
When all files have been downloaded, the user should de-select the Load To Local Disk function from the Options menu.
REMEMBER: The sidescan sonar data files are binary encoded and cannot be viewed directly. Attempts to view the files in a text window will result in an blank window being displayed. The sidescan sonar data listing with cross-references to the data files is simply to aid the user in identification and downloading of desired files.
The navigation data is stored on the CD-ROM as an ASCII file and may be viewed by clicking on the appropriate link to the selected cruise identifier under the heading NAVIGATION DATA from the Intro.Page. Once selected and viewed, the user may scroll through the data file using the selected WWW browser.
To download the navigation data from CD-ROM the user has two options. First, he or she may follow the steps described above for downloading the sidescan sonar data. A second method of downloading the navigation data is available when viewing the data file in the text window. The user may then select the Save As option from the pulldown menu from the File option located on the menu bar. When prompted, the user may then enter the directory and filename of where the data file will be stored on disk.