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Overview

Data

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Data

The Data section provides access to the MODIS data products in the LAADS archive through the Search page and the FTP Site page. An overview of what data products are available can be found through the Data Availability page. All previous and current orders may be tracked through the Track Orders page.

Search

The search pages allow users to search for MODIS products either by specifying criteria that applies to the products or by specifying the products file names.

Search for Products

The following criteria may be specified when searching for products:

Product Selection

The product selection section allows users to select one or more MODIS products. Products are listed in a scrolling box and labeled with the product's Earth Science Data Type (ESDT) and a brief description. You may select products by clicking on the product in the scrolling box. This will highlight the product's ESDT and description. You may select as many products as you wish. However, some browsers require you to hold down the CTRL key while clicking on the product to select more than one.

The products are organized by satellite/instrument and group. Whenever a new satellite/instrument or group is selected, the products listed in the scrolling box change to match the new satellite/instrument and group. Any highlighted products are carried over from the previous group. If you do not have javascript enabled in your browser, you will need to click the "Update" button next to the satellite/instruments and groups to force the products listed in the scrolling box to change.

Temporal Selection

The temporal selection section allows users to input a date and time range. The date and time must be in one of the following formats:

MM/DD/YYYY [HH:MM:SS AM|PM] or YYYY-DDD [HH:MM:SS AM|PM]

where MM is the month, DD is the day of month, YYYY is the year, DDD is the day of year, HH is the hour, MM is the minute. and SS in the second. The hour, minute, and second are optional. If not specified, they will default to 12:00AM.

By default, the start date and time is set to the launch date of Terra and the end date and time is set to the current date.

Collection Selection

The collection selection section allows users to select a collection. In the pull down menu, the collection is specified first followed by a description of the collection.

Spatial Selection

The spatial selection section allows users to specify their area of interest using latitude/longitude coordinates. The area of interest may be entered either by typing the coordinates into the text boxes, dragging your mouse on the map to draw a rubber band box around the area of interest, or selecting one of the predefined regions. The last two options are only available to Javascript enabled browsers.

There are six different ways to specify coordinates in the text boxes. They are:

  1. North, West, East, South
  2. Center Lat/Lon, delta Lat/Lon
  3. Upper Left Corner, delta Lat/Lon
  4. Upper Right Corner, delta Lat/Lon
  5. Lower Left Corner, delta Lat/Lon
  6. Lower Right Corner, delta Lat/Lon
A pull down menu located above the text boxes is used to select the way to specify the coordinates. If Javascript is enabled, the labels on the text boxes will change to match the way the coordinates are specified. If Javascript isn't enabled, you will need to click on the "Update" button to update the text box labels.

Coverage Selection

The coverage selection section allows users to select coverage options. The coverage options are as follows:

  • Day - granules contain day data only
  • Night - granules contain night data only
  • Both - granules contain both day and night data

For example, if you were to select the Day and Night coverage options, the granules returned would contain either day data only or night data only. None of the granules would contain both day and night data.

Coverage options are not defined for all products. Therefore, the coverage options checkboxes are disabled unless you have selected products for which the coverage options are defined.

Quality Assurance Selection

The quality assurance selection section allows users to select a start and end range for the percentage of missing data.

Saved Parameters Selection

You may save your search parameters to a file on your computer for later use. Simply enter the desired search parameters, input a file name in the saved parameters selection section, and click "Save". The parameters are saved as name=value pairs in a file with the file name you specified on your computer.

To load parameters previously saved to a file, simply enter the file name in the saved parameters selection section and click "Load". You may also click on "Browse" to find the file.

Search for File Names

File names may also be specified when searching for products. File names usually have a format like one of the following:

ESDT.AYYYYDDD.HHMM.CCC.YYYYDDDHHMMSS.hdf
ESDT.AYYYYDDD.hNNvNN.CCC.YYYYDDDHHMMSS.hdf

where ESDT is the product name, YYYYDDD is the product's data year and day of year, HHMM is the product's hour and minute for granule data, hNNvNN is the product's horizontal and vertical tiles for tiled data, CCC is the product's collection number, and YYYYDDDHHMMSS is the product's production year, day of year, hour, minute, and second.

If you are unsure of the production time or would simply like to specify all granules for data day 2005-001, you may specify partial file names. For example: MOD03.A2005001

Order

Search Results

Once you have submitted your search, a results page is returned with a summary of the search parameters and a table of the product files that matched the search parameters. The table is sorted by time and product. It includes the product file's name, size, online status, and links to any browse images associated with the product file. Clicking on the browse image links will open the browse image in a new window. Individual product files may be downloaded directly by clicking on the file name.

If there are more than 10 product files, the table is split between several pages, with 10 product files per page. Links to each page can be found at the top of the table. There is also a "View All" link if you wish to view all the product files at once. Please use this option with caution. Most browsers will have trouble displaying a table with thousands of rows.

Also included in the table are checkboxes which allow you to modify which product files are included in your order. By default, the checkboxes for all product files are selected. You may remove product files from you order by clearing the product file's checkbox. You may also select or clear the checkboxes for all product files by clicking the "Select All Checkboxes" or "Clear All Checkboxes" buttons below the table. When the table is split between pages, these buttons apply to all product files, not just the product files on the current page.

Two ordering options are presented at the bottom of the results page. You may choose to post process the selected product files before delivery or have the product files delivered without additional post processing. If you choose to post process, you will be asked to provide the criteria for post processing.

Post Processing

When you choose to post process your product files, you will be asked which post processing steps to apply to your product files. The possible steps include:

  • Subset by parameter
  • Subset by geographic area of interest
  • Mosaic tiled products
  • Reproject tiled products using new map projection
  • Convert tiled products to geoTIFF format
  • Data Quality Screening Service (DQSS)

Once you have selected the steps to apply to your product files, you will be asked to provide specific information for each step.

Delivery Method

The last step in the ordering process if to select a delivery method. At this point, you are asked to provide you email address. This allows us to contact you if there are any problems filling your order. It also allows us to notify you when orders that are not available immediately, such as post processed orders, become available.

There are two delivery methods: FTP Pull and FTP Push. If you choose FTP Pull, we will stage the products on our FTP server and provide instructions for downloading the products. If you choose FTP Push, we will push your products to your FTP server. If you choose this method, you must provide us with the information required to login to your FTP server and copy files to it.

Data Availability

The Data Availability page provides an overview of the MODIS data products available in the LAADS archive. The page lists each year since the start of the mission across the top of the page and product groups down the left hand side of the page. At the intersection of each year and product group is a color bar that represents whether most to all, some, or little to no data is available for the year and product group. A key to the color bars is found at the bottom of each page.

You may "drill-down" to more details by clicking on the color bars. For example, by clicking on the color bar at the intersection of year 2006 and group Terra Atmosphere Level 2, a page that lists each month in 2006 across the top of the page and the ESDTs in the Terra Atmosphere Level 2 group down the left hand side of the page is displayed. At the intersection of each month and ESDT will again be a color bar that represents whether most to all, some, or little to no data is available for the month and ESDT.

You can "drill-down" further by clicking on these color bars. For example, by clicking on the color bar at the intersection of month April and ESDT MOD04_L2, a page that lists the number and size of files across the top of the page and the days in the month down the left hand side of the page will be displayed. At this point, instead of color bars, a the number and size of files for each day is displayed.

At any time, the collection displayed can be updated by selecting a collection from the pull-down menu at the top of the page and clicking the "Update" button.

FTP Site

All of the MODIS products in the LAADS archive are available through our anonymous FTP site on ladsweb.nascom.nasa.gov. The directory structure of the site was designed so that users can easily browse the site without using the web interface. The directory structure is as follows:

allData/<collection number>/<product name>/<year>/<day of year>/<file name>

Track Orders

The "Track Orders" page allow users to track orders for which an email address was provided. This page allows you to view details of previous orders and to cancel or release current orders.

After entering your email address on the "Track Orders" page, a list of your previous orders is returned. This list includes the order ID, the submit time, the complete time, the state, and the delivery method. You may view the order details by clicking on the order ID. The order details include retrieval instructions and a list of files included in the order. For post processed orders, the input files are listed. If an order has not yet completed, the order details will include a description of the order's status.

You may also cancel orders that have not yet been delivered and relase orders that you have finished downloading from this page. When your order is in an active state, a checkbox appears in the "Cancel/Release" column. You may cancel or release the order by selecting the checkbox and clicking the "Cancel or Release Orders" button. You may also refresh the the list of previous orders by clicking the "Refresh Page" button.

Images

The Images section provides access to browse images of the MODIS data products in the LAADS archive

Global Browser

This page displays thumbnail images of the global browse images for the most recent month available. You may use the browse bar to change the satellite, date, parameter, or collection of the thumbnail images displayed. You may also page through subsequent months by clicking the "Previous" and "Next" links above the thumbnail images.

Below each thumbnail image is the name of the product file associated with the browse image. You may order any of the product files by selecting the product file's checkbox and clicking the "Order Selected Products" button. You may also select or clear the checkboxes for all product files by clicking the "Select All Checkboxes" or "Clear All Checkboxes" buttons below the thumbnail images.

By clicking on a thumbnail image, you may view a higher resolution image. From this page, you may also download the product file associated with the browse image, view a side by side comparison of the current parameter with other parameters, and view the full resolution image in a new browser window.

Granule and Tile Browser

This page displays the a global browse image for the most recent day available. You may use the browse bar to change the satellite, date, parameter, or collection of the global browse image displayed. You may also page through subsequent days by clicking the "Previous" and "Next" links above the global browse image. A link to a high resolution image of the global browse image can be found below the browse image. If a global browse image is not available, a default global image is displayed.

To view individual browse images, select a region by entering coordinates into the Bounding Box Coordinates text boxes. Users with Javascript enabled browsers may also select a region by dragging their mouse on the global browse image. Once you have selected a region, click the "Get Granule Images" button. Thumbnail images of the individual browse images in that region are returned.

If more than 4 thumbnail images are returned, they are split between several pages, with 4 thumbnail images per page. Links to each page can be found above the thumbnail images. There is also a "View All" link if you wish to view all the thumbnail images at once. Please use this option with caution. Most browsers will have trouble displaying thousands of images.

Below each thumbnail image is the name of the product file associated with the browse image. You may order any of the product files by selecting the product file's checkbox and clicking the "Order Selected Products" button. You may also select or clear the checkboxes for all product files by clicking the "Select All Checkboxes" or "Clear All Checkboxes" buttons below the thumbnail images. When the thumbnail images are split between pages, these buttons apply to all product files, not just the product files on the current page.

By clicking on a thumbnail image, you may view a higher resolution image. From this page, you may also download the product file associated with the browse image, view a side by side comparison of the current parameter with other parameters, and view the full resolution image in a new browser window.


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