1. Access to Map Images The images are available on the Internet node cdiac.esd.ornl.gov (or 128.219.24.36). The images may be accessed via FTP TCP/IP (Transmission Control Protocol/ Internet Protocol). Following is the information necesssary for a typical user to access the images. The user should consult communication documentation at his/her installation for exact commands. FTP information: Enter "ftp cdiac.esd.ornl.gov" Enter "anonymous" when user name (or ID) is requested Enter your email address when password is requested Enter the FTP command to allow retrieval of non-ASCII files (usually "binary" or "image" - may be different for your installation) Enter "cd pub" to change to the public directory The user must then change to the appropriate directory and subdirectory, as described below. The image management structure is a hierarchical database, implemented using the directory structure of the UNIX operating system. The root directory for all the images is "images", with subdirectories "ce" (cylindrical equidistant projection), "loci" (data location maps) and "polar" (polar orthographic projection). The user must also select the time period subdirectory. Following is the subdirectory and file structure for the "images" directory: Directory/file name Description of contents ------------------- ----------------------- images/ce/annual cylindrical equidistant projected annual images images/ce/monthly cylindrical equidistant projected monthly images images/ce/seasonal cylindrical equidistant projected seasonal images images/loci/annual data location annual images images/loci/monthly data location monthly images images/loci/seasonal data location seasonal images images/polar/annual polar orthographic projected annual images images/polar/monthly polar orthographic projected monthly images images/polar/seasonal polar orthographic projected seasonal images images/readme.dat documentation on construction of the images images/readme.img the file you are reading images/shareware shareware for viewing GIF files Each annual subdirectory contains 141 images, each seasonal subdirectory contains 563 images, and each monthly subdirectory contains 1656 images. To retrieve a GIF image, the user must change to the directory that contains the image (by entering "cd directory name", e.g. "cd images/ce/monthly"), then access the particular images of interest. The file containing an image has been named to reflect the time period of the image. The GIF images have been named using the following convention: xxyyyy.gif, where xx is 05 in the annual directory 01-04 in the seasonal directory (winter, spring, summer, fall, respectively) 01-12 in the monthly directory (January, February, ..., December) yyyy is 1851 to 1991 Retrieval of an image is accomplished by entering "get image name" (e.g. "get 031979.gif"). Multiple images can be retrieved with a single command, as in the following examples: To retrieve all images in the directory, enter "mget *.gif" To retrieve all February images in the monthly directory, enter "mget 02????.gif" To retrieve all 1953 images in the directory, enter "mget ??1953.gif" The system will prompt you to determine which of the multiple images you wish to retrieve. To inhibit the system from prompting during multiple image retrieval, enter "prompt" prior to entering the "mget ..." command. When you have completed retrieval of the images you want, enter "quit". A CD-ROM version of the atlas is also available. If you would like a copy of the CD-ROM version, contact Frank Keimig by mail at Department of Geology and Geography, Box 35820, University of Massachusetts, Amherst, MA 01003-5820, by phone at 413-545-0659 or at Internet address frank@climate1.geo.umass.edu. 2. Software There are a number of GIF file viewers available as shareware, and many users are currently using one of those viewers. For users needing a GIF viewer, we have made three viewers available in the directory images/shareware. These viewers are described below. Computer Viewer file -------- ----------- PC cshowa.exe Macintosh quickgif1.0.sit.hqx Workstation with the X Window System xv-3.00a.tar.Z Each software package is shareware, which implies that if you use it, the author's request for payment should be honored. Registration and payment will provide you with notification of future upgrades and in some cases allows you to obtain enhanced versions of the software. To retrieve any one of the files via FTP: Enter the FTP command to allow retrieval of non-ASCII files (see above) Enter "get viewer file name" (e.g. "get xv-3.00a.tar.Z" - note that UNIX is case-sensitive) To create a usable form of the shareware, follow the directions below. a. PC Create a directory on your hard drive, and copy "cshowa.exe" to that directory. From within that directory enter "cshowa". The file is a self-extracting archive, which will be expanded to create all of the files necessary to use CompuShow Standard Version 8.61a. The ".doc" files explain all that is necessary to install, implement, and register the software. Be sure to note the necessity for selection of a video driver for some monitors in setup.doc and drivers.doc b. Macintosh The file quickgif1.0.sit.hqx must first be decoded from BinHex4 format, and the resulting ".sit" file must be "unstuffed" from StuffIt format. QuickGIF is the application program QuickGIF, version 1.0. The "Docs" and "Text" files explain all that is necessary to implement, and register the software. The content of the files is the same; the "Text" file is in text format, and the "Docs" file is in MacWrite format. c. Workstation Using the X Window System Use the UNIX commands to "uncompress" and "untar" xv-3.00a.tar.Z. This will create all of the files necessary for implementing XV, version 3.00. XV must be compiled from source files for your particular workstation. The INSTALL file provides instructions for compiling, the README file provides instructions for registering the software, and the DOCS subdirectory contains other documentation for using the software. The are many other GIF image viewers available, and you may currently be using one. Most of the viewers are available as shareware, and many are available at anonymous FTP sites. In addition, some workstations are distributed with executable graphics viewers installed. 3. Displaying map images Users should have a monitor with the capability of displaying 256 colors (SVGA, 8-bit RGB color). The monitor is necessary to take advantage of the high resolution color images and to display them correctly. To display an image, invoke the software, referring to the directory or folder which contains the image (or images) of interest. If you are using the enhanced version of CompuShow on a PC, you can set up a script to display several images consecutively. To do this, ftp the file atlas.scr from the "shareware" directory to the directory on your hard drive in which CompuShow resides. In the file atlas.scr, use a text editor to change "D:\DIR" to the drive name and directory name in which the images reside. Also, change "FILE1.GIF", "FILE2.GIF", etc. to the names of the files you wish to display, and change "?" to the number, letter or character for the video display mode you use (e.g. "N" for 1024x768x256 - see CompuShow documentation). You can add more three-line entries for additional files. When your editing is completed, save the file under a new name with an extension of ".scr". Now enter the command "cshow /sxxx.scr", where "xxx.scr" is the new name you just used. The images will be displayed, one at a time. Pressing the "Enter" key will display the next image. After the last image has been displayed, the first image will again be displayed. To stop the display loop, press the "Esc" key. If you are using the enhanced version of QuickGIF on a Macintosh, several images can be displayed consecutively in a loop. Choose "Open", and then select all images you want in the loop in the "Open" dialog box. Then, click on "Show". In the "Show" dialog box make sure that the zoom options are off, and set the "Minimum Delay" to the desired time delay between images. The documentation that is available with the enhanced version describes the implementation of the display loop. 4. Questions and comments Questions on any of the above material and comments on the atlas should be submitted to cdp@stc10.ctd.ornl.gov or frank@climate1.geo.umass.edu 5. Errata Several image errors have been encountered in developing this atlas. The errors are described below. a. Due to incorrect data in the July, 1977 monthly mean 500 mb height grid, the July, summer and annual 500 mb height images for 1977 (in both cylindrical equidistant and polar projections) are incorrect. b. The June, 1908 sea level pressure image (in both cylindrical equidistant and polar projections) does not contain proper contouring. c. The Winter, 1908 sea level pressure cylindrical equidistant projected image does not contain proper contouring. The polar projected image for this date is fine. d. The June, 1977 and July, 1977 sea level pressure polar projected images do not contain proper contouring. The cylindrical equidistant images for those two dates are fine. Acknowledgment. This work was supported by a grant from the Environmental Sciences Research Division, U.S. Department of Energy.