CLASS Help Documents

Introduction to CLASS

The National Oceanic and Atmospheric Administration (NOAA) Comprehensive Large Array-data Stewardship System (CLASS) is NOAA's premier on-line facility for the distribution of NOAA and US Department of Defense (DoD) Polar-orbiting Operational Environmental Satellite (POES) data and derived data products. CLASS is operated by the Information Processing Division (IPD) of the Office of Satellite Data Processing and Distribution (OSDPD), a branch of the National Environmental Satellite, Data and Information Service (NESDIS).

CLASS maintains an active partnership with NOAA's National Climatic Data Center (NCDC). NCDC, the permanent US Archive for POES data and derived data products, supports CLASS through a user-interactive Help Desk facility and through the provision of POES supporting documentation, including the NOAA Polar Orbiter Data (POD) User's Guide and the NOAA KLM User's Guide. Additionally, NCDC and CLASS share data distribution responsibilities for Defense Meteorological Satellite Program (DMSP) data under a Memorandum of Understanding with the National Aeronautics and Space Administration (NASA) for the Earth Observing System (EOS) Program.

CLASS provides data free of charge. Anyone can search the CLASS catalog and view search results through CLASS's World Wide Web (WWW) site. Users who wish to order data are required to register with their names and email addresses. CLASS distributes data to those users via FTP services.

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Background

CLASS (originally called Satellite Active Archive), was established as a demonstration prototype for electronic distribution of POES data in 1994, and became operational in July 1995. During that first month, 379 Advanced Very High Resolution Radiometer (AVHRR) Level 1b data sets were distributed to 27 customers via the emerging Internet. During the first five years of operation, the average monthly volume of data distribution increased to 65,000 data sets with a total size of 1.2 TB, and the SAA customer base grew to more than 10,000 registered customers. The active archive was expanded during that period to include TIROS Operational Vertical Sounder (TOVS) data, Defense Meteorological Satellite Program (DMSP) data, Radarsat Synthetic Aperture Radar (SAR) imagery, operational (near-term) satellite-derived products, and climatic (time-series) satellite-derived products.

Around this Site

Guest Users

If you are new to CLASS, you may view the site as a "Guest User." If you choose to search the CLASS inventory before registering, you may do so; however, you will be prompted to register before placing an order. Click on the "Register" link at the top of the page to go to the "User Profile" page to become a registered user.

Once you have filled out the User Profile Page, you will be sent an email with your user name (you choose a password when registering). At this point, you may log on, search our web site, and place orders at your convenience.

Please note that some of the data delivered by CLASS requires special processing software. You can write your own or you can order commercial products. For a small sample of commercially available software packages, please see the FAQ Section titled "Satellite Data Viewing Software."

CLASS delivers data electronically via FTP. Once you place an order, you will receive an Order Verification email stating your order number and indicating that your order is being processed. Once processing of each item within your order has completed, you will receive a Delivery Notification email providing instructions on how to pull your data. On the User Preferences Page, you may specify whether or not you wish to receive these Order Verification emails and whether you want to receive one Delivery Notification email per item or only one notice per order.

Page Layout

The top of the page shows the standard NESDIS banner on the left. On the right is the option to "Log In" if you have previously registered with the CLASS web site. Guest Users may view information and conduct searches but will be prompted to register before ordering data from CLASS. A link to the Home Page is included in the banner area as well as a link to these help pages.

On the left hand side of each page is a navigation area, which allows you to move to various pages within the site as well as to related sites outside of CLASS.

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To the right of the Navigation/tool bar is the main body of the page. This is where the information about the search criteria, search results, order, user profile, or the user preferences is displayed.

Getting Help

If you are unable to find what you are looking for in these help pages, please contact our help desk at info@class.noaa.gov.

Accessing the Site

There are two ways to enter the CLASS web site. You may enter as a "Guest User" or you may "Log In" as a registered user.

If you would like to browse the CLASS web site, you may do so as a "Guest User." You can search the site as you like. Before placing an order, you will be prompted to register by filling out the "User Profile" form. A link to the "User Profile Page" is located on the left side of the page or you can use the "Register" link at the top of the page.

If you have previously completed your User Profile, please click on the "Log In" button on the top, right-hand side of the Home Page. You will then be prompted to enter your CLASS user name and password. After entering this information, you will be redirected to our Site Entry Page from where you can search the site and place orders for data.

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Registering as a CLASS User

The User Profile Page allows you to create and update the information stored in your CLASS user profile. To register initially, fill in the appropriate fields and click the Add button. To modify your profile, type over the displayed values you wish to modify and click the Update button.

Fields indicated with an asterisk (*) are required for registration.

No personal information is distributed to any outside source. See our Privacy Policy for more information.

Once you have selected your User Preferences, click the Update button located at the bottom of that page.

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Access to Available Products

The CLASS web site allows you to search the inventory based on each available type of product. The product menu allowsyou to select the desired product and press go, at which point you are taken to the Search Criteria Page that presents information and search criteria relevant to that product.

Search Criteria Page

The Search Criteria Pages allow you to search for all data sets that meet any combination of available criteria for that data type.

The following Search Criteria Pages are available:

Select the options based on the Selection Criteria available for the requested product.

The Search Criteria Pages contain the following sections:

Once you have specified all of your desired search criteria, click on the "Search" button at the bottom of the page. You will be provided with the results from your search in a "Search Results Page."

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Search Results Page

The Search Results Page displays the results of the search you requested based on the search criteria you entered. The format and functionality of the Results Page differ depending on which broad category of product type you searched upon.

There are two types of products available: ordered and browser.

Ordered Products encompass data types that are obtained from CLASS by placing an order and subsequently retrieving the data via FTP. Browser products are smaller in size and can be accessed only through the web browser.

Results are displayed on a separate browser window in tabular form, a few to a page.
The number of hits can be found to the right, above the results table. Depending on the number of hits found, you may have more than one page of results available. To change to another page of results, you can go directly to a specific page by selecting the page number in the "Jump to" section. Automatically, you will be taken to the specified page. You can also use the "Next" and "Previous" buttons to go through the pages in sequential order.

The results table depicts specific information related to each hit. Additional details about a specific hit may be obtained by clicking on the View Details button for that hit. See below for details about the Details Page.

A hit may be placed in (removed from) your Shopping Cart by checking (unchecking) the box in the Shopping Cart column of the table next to that hit. You may use the SelectAll and DeselectAll buttons to automatically select or deselect a large number of hits. Note that there are limits to the number of items of each data type that you may place in the Shopping Cart. As a result, the SelectAll button may not place all of your hits in the Shopping Cart.

The Update button updates your Shopping Cart with any selection changes you have made. The Goto Cart button updates your cart while also bringing you to the Shopping Cart Page from where you can continue processing your order.

For applicable data types, a Generate Map button will be present. If you click on this button, a new browser window will be generated and will contain a map depicting the overlap between all of the hits shown on the current Results Page and the geographic region you used for your search. The color of each hit’s overlap region matches the color of that hit in the results table. All of the functions of this map window are described here. Maps are created with the Generic Mapping Tools (GMT).

If you have placed a number of searches covering different ordered product data types, links to each family’s results page will appear to the left of the results table. Simply click on the family name to bring up that family's results page. You will see that a second link for each searched upon family is labeled (ASCII). This link will display an ASCII file showing all of your hits for that search along with the corresponding search criteria.

Depending upon the requested output format for your particular data type, you will either be shown results displayed directly to your browser window or you will be shown a dialog box through which you may download the results file. For results displayed directly to the window, you may use your browser to save the results locally.

You may have multiple hits for your search, so be sure to look at the selection menu at the top of the results page. Choose the result you wish to view and hit the Go button to display that result.

If you performed a geographic search and chose “Plotted image GIF” as your output format, below the image you’ll see a display of the area depicted by the GIF image.

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Shopping Cart

The Shopping Cart Page displays information about each data set you have chosen to order. The total number of kilobytes of data you are ordering is displayed. You may choose to remove any data set from your order by unchecking the box in the "Order" column of the Shopping Cart table. You may then recalculate the size of your order by clicking on the "Recalculate Size" button. Like on the Results Page, you may obtain more detailed information about each data set by clicking on the numbered button in the "View Detail" column of the table. This will bring you to the Details Page discussed earlier .

AVHRR data sets have more order options: Geographic Subset, Bits/Pixel, and Channel Numbers. As AVHRR data sets are placed in the Shopping Cart, the ordering preferences specified in the User Profile Page are applied. These parameters can be modified once the data set is placed in the Shopping Cart.

For TOVS, ATOVS, and AVHRR data items, you may choose to include an archive header record with each data item. This TBM or ARS archive header record includes information about the order parameters applied to that item.

If you have already registered, your email address from your User Profile will appear in the notification field near the top of the page. If you want notifications for the current order to be sent to a different address, enter that new address into the field.

You may also enter an Order Comment which will be included in your order notification emails.

Once you are ready to submit the order, click on the "Place Order" button. Note, if you are a new user and have not yet registered, there will not be a "Place Order" button. Instead, it will be a "Register" button, which will take you to the user profile screen to register. Once registered, you may continue with your order.

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Order Query Page

The Order Query Page is displayed after you have clicked on the "Order Query" link on the navigation menu. The page automatically displays information about all of your orders placed within the past 72 hours. You may also choose to display information about a specific older order by filling in the order number and clicking on the "Query Orders" button. Additionally, you may enter some number of hours and click on the "Query Orders" button. All orders placed within the entered time frame would then be displayed.

To capture recent updates to the order status information for your orders, click on the "Query Orders" button.

Please note that you may only view the status of orders that have been submitted under your user ID. However, the number of line items in progress refers to all orders currently being processed at CLASS. This number gives you an idea of the current system load and can be indicative of how quickly your current orders may process.

The information displayed in the Order Status table is as follows:

Refers to the unique number assigned to the order by CLASS. This number corresponds to the order number given in the order verification and notification messages.

Refers to the unique number assigned to the order line item by CLASS. This number corresponds to the line item number given in the order verification and notification messages. Note that the order line item number may appear as blank in the table if the order has just been submitted. This is because the line item number has not yet been assigned. Assuming it has been assigned, you may click on the number to view details about this line item. These details will include the actual and estimated size of your delivered line item, expressed in kilobytes, the applicable order options applied to the line item, and the geographic search and subset parameters, if applicable.

The name of the ordered data set .

Indicates the last time the status of this line item was modified.

The status of the line item. The possible values are as follows:

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