This tutorial covers the organization of the file system, different methods of displaying the images and different methods to locate latest and archived imagery.

We have tried to design the web site with the user in mind. Improvements to the site continue in an effort to make location and display of Operational Significant Event Imagery as fast and easy as possible.

Site browsing is accomplished using the navigation bar. There are two versions of this tool, one is based on the Java language and the other is conventional HTML for those with browsers that do not support Java.

If you do not see either of these or the frame that should contain them, please enter this help section through the front page of our website at www.osei.noaa.gov

The organization of images on this site is based on the significant event that they display. In the navigation bar to the left, you will see eleven categories of events we monitor daily and one directory labeled "Current" which contains the latest imagery we have produced.

The directory labeled "Unique" contains imagery of events that are not classifiable under any other directory or of multiple events in one image.

To view files contained in a specific directory, click on the directory name in the navigation bar. Files are organized first by geographic location of the event depicted, then by date.

You will see one of two page styles depending on the progress of our site renovation. (NOTE - Current, Dust and Fires directories have been improved to Style 2 as of 03/10/99) Style 1 is the standard directory listing which shows directories organized by name. Style 2 is a Perl-generated "region select" page which displays maps of the regions for which images exist and then presents a page with files organized by date and subdivided by week.

NOTE: The exception to the organization method is the "Tropical" directory which is organized first by geographic location, then by storm name, then by date.

Also note that the "Current" link does not have a region-select page but takes you directly to a list of the latest imagery produced by OSEI.

Clicking on the filename of an image will display the image in the right-hand frame. Most OSEI images are too large to completely appear in this frame and scroll bars will be provided by your browser at the side and bottom of the right frame.

This brings us to the two major issues involved in the display of OSEI products: time of download and image dimensions.

The unavoidable consequence of high detail and resolution in OSEI products is large file sizes. The size of a file is proportional to the time it takes to download and display an OSEI product on your system. Download time can be reduced by a faster Internet connection, a faster computer, and accessing of OSEI products during off-peak hours.

To help a user decide if the download time is worth viewing the image, we started the practice of creating a "preview image" for each OSEI product created. Most OSEI products created on and after January 1999 have preview images associated with them. These images are smaller, less detailed versions of their "standard" counterparts which have been designed to be more useful than a conventional thumbnail but still small enough to load quickly.

Preview images are intended to help the user determine whether they have sufficient interest in the image before trying to download the standard version of the product. Please note that the smaller file size and dimensions of the preview images negatively affect the clarity and detail of events captured in the image but that traditional OSEI image quality has been preserved in the standard version.

The preview images can be identified by the letter "L" which appears just before the extension on the filename (NOTE: The filename of the preview is the same as that of the standard except for this "L" addition) or, in Style 2, by the red letter "P" which appears in the directory listing next to the filename of the image.

Most standard OSEI products are at least 1280X1024 in pixel dimensions and have an average file size of 600K.

As mentioned before, the dimensions of OSEI products creates a problem in viewing the entire image without having to scroll. Even with a large monitor, the size of the right frame on this site is too small for most of the OSEI products. As a partial remedy, the entire image can be opened in the web browser window. The method for doing this depends on the browser but one of these should work (the final suggestion should work on all browsers - Illustrations of menus are taken from Netscape 4.07 and MSIE 4.0):

• METHOD 1: Most versions of Netscape have a command in the right-click menu (accessed by right-clicking with the mouse pointer in the browser window over the image) called "Open Image" or "View Image". Use this to view the image in a full browser window.
  

  Microsoft Internet Explorer has a command in its right-click menu (accessed by right-clicking with the mouse pointer on the link to the image) called "Open in New Window". Use this to view the image in a full browser window.
  

• METHOD 2: You can save the image to your local drive and open it in a graphic display program. Most of these programs allow you to display an image fullscreen and to adjust the size of an image for better viewing.
  

  To save the image, right-click on the image (both MSIE and Netscape). Netscape has an option called "Save Image As...", MSIE has an option called "Save Picture As...".
  

• METHOD 3: You can type the address of the image in the browser address window and hit ENTER. This will load the image into the full browser window.

Accessing the latest imagery on the OSEI web site can be done in a few different ways:

• Subscribe to our Daily Operational Significant Event Imagery Report (The DOSEIR). Each workday you will receive an e-mail version of this report. Most e-mail software creates "hot" links when a line begins with "http". If configured properly, this allows you to click on the links in the e-mail and go directly to the image in your default web browser. If the links fail to work, simply copy the address and paste it in your browser address window.

• Read the web version of the DOSEIR. This version will also contain links which will take you directly to the image. The report can either be read in the right-hand frame or in a remote window. Use of this remote window feature requires a Javascript-capable browser.

• Although the DOSEIR contains a short narrative about each event and image which may prove useful in helping you determine whether or not you're interested in downloading the file, you can forego the report and visit the "Current" directory which contains a list of the latest imagery produced by the team.

In addition to the latest imagery, our web site carries a substantial archive of imagery we have produced. These products have been stored in archive subdirectories of the main event directories. If you are looking for imagery from a specific event or in a specific location, the following notes may be useful:

• Click on the appropriate event directory in the navigation bar.
  

• If the event directory has been upgraded to Style 2, click on the appropriate region in the maps provided. Otherwise, choose the directory of the appropriate geographic location. If no link is available, imagery of that event type in the specified location has not been produced.
  

• You are then taken to a page with a list of files. Each of these is an image created of the specified event in the specified location. You should review our filename tutorial to help with selection of specific files. The three-digit number in the filename is the Julian Date of the image.

• If the directory is Style 1, the column labeled "Last Modified" is useless as it only tells you the date on which the file was last moved, modified or re-named. Style 2 reads the Julian Date from the filename itself (which contains the date of the satellite pass used to make the image) and translates it to a conventional date for ease of use. Select files from the dates in which you are interested. For help with conversion of Julian Dates to conventional dates, click here.

• The image will appear in the right frame. Scroll around the image to see the event or use one of the methods mentioned above to get a better look.