Data are easy to locate if the data files are well organized. Well organized files also make data more accessible to anyone who uses the system. Using consistent naming conventions helps keep image files well organized and accessible.
Consistent Naming Convention
Many processes create an output file, and every time a file is created, it is necessary to assign a file name. The name that is used can either cause confusion about the process that has taken place, or it can clarify and give direction. For example, if the name of the output file is image.img, it is difficult to determine the contents of the file. On the other hand, if a standard nomenclature is developed in which the file name refers to a process or contents of the file, it is possible to determine the progress of a project and contents of a file by examining the directory.
Develop a naming convention that is based on the contents of the file. This helps everyone involved know what the file contains. For example, in a project to create a map composition for Lake Lanier, a directory for the files may look similar to the one below:
From this listing, one can make some educated guesses about the contents of each file based on naming conventions used. For example, lanierTM.img is probably a Landsat TM scene of Lake Lanier. The file lanier.map is probably a map composition that has map frames with lanierTM.img and lanierSPOT.img data in them. The file lanierUTM.img was probably created when lanierTM.img was rectified to a UTM map projection.
Keeping Track of Image Files
Use a database to store information about images to track image files (.img) without having to know the name or location of the file. The database can be queried for specific parameters (for example, size, type, map projection) and the database returns a list of image files that match the search criteria. This file information helps to quickly determine which images to use, where it is located, and its ancillary data. An image database is especially helpful when there are many image files and even many on-going projects. For example, you could use the database to search for all of the image files of Georgia that have a UTM map projection.
ERDAS IMAGINE Image Catalog
ERDAS IMAGINE Image Catalog database is designed to serve as a library and information management system for image files (.img) that are imported and created in ERDAS IMAGINE. The information for the image files is displayed in Image Catalog CellArray™. Use this CellArray to view all of the ancillary data for the image files in the database. When records are queried based on specific criteria, the image files that match the criteria are highlighted in the CellArray. It is also possible to graphically view the coverage of the selected image files on a map in a canvas window.
When it is necessary to store some data on a tape, use ERDAS IMAGINE Image Catalog database to archive image files to external devices. The Image Catalog CellArray shows which tape the image file is stored on, and the file can be easily retrieved from the tape device to a designated disk directory. The archived image files are copies of the files on disk—nothing is removed from the disk. Once the file is archived, it can be removed from the disk.