How to Navigate the LAADS Online Archive to Download Data
The LAADS Online archive offers all public product collections that can be downloaded without a registered user conducting a search. We offer two pathways to find and acquire the requisite data:
Science domain-driven navigation
This capability is designed for users to intuitively follow the science domain attributes to target datasets of interest. This (and the /allData tree) method is appropriate for seasoned users who know what datasets they require for their research or applications, and can afford to forego any post-processing transformations. It also is beneficial for those who depend on a constantly acquired time-series of products for regularly computed application requirements.
This capability allows users to naturally follow the taxonomic structure by selecting their discipline (e.g., atmosphere, land, Level-1, etc.), product suite (e.g., Aerosol, Land Surface Reflectance, etc.), particular products, year, and day-of-year (January 1 is 001 and December 31 is 365, all other dates are listed in this same method by their sequential number of day between 001 and 365 ), etc. For instance, the following pathway provides science domain-driven access to the SNPP VIIRS Deep Blue Aerosol L2 products from January 4th 2015:
http://ladsweb.modaps.eosdis.nasa.gov/archive/Science Domain/Atmosphere/Aerosol/VIIRS SNPP C1.0 - Deep Blue Aerosol L2 6-Min Swath 6 km/2015/004/
Once users are on this page that lists all datasets for that day-of -year, they have the option to select and download one or more datafiles. They can also download multiple files at once by individually selecting rows in the table, selecting multiple rows by holding down the Shift key, or choosing “Select All” to select all files. Once the user has selected the files desired, click "Download Selected" to confirm their multi-file download.
/allData tree-based navigation
Registered users can navigate through the LAADS /allData tree, and directly download their preferred data products. To be able to download data in this method, the user must know the product’s collection number and short-name. Another attribute, the “Archive Set,” is a numeric identifier that primarily relates to archive storage. Users do not have to know or keep track of archive set numbers, but need to understand how they map to collection numbers. The table below identifies the LAADS DAAC’s public product collection numbers and their corresponding archive set numbers. Product short-names are used within the archive directory structure, but they are not very descriptive and sometimes difficult to remember, so many users use the LAADS product descriptions to find each product’s short-name.
|Collection||Archive Set number||Mission | Instrument|
|MODIS Collection 6||6||Terra MODIS, Aqua MODIS|
|MODIS Collection 5.5||55||Terra MODIS|
|MODIS Collection 6.1||61||Terra MODIS, Aqua MODIS|
|VIIRS Collection 1 (Land)||5000||SNPP VIIRS|
|VIIRS Collection 1 (L1, Atmos.)||5110||SNPP VIIRS|
|VIIRS Collection 1.1 (Atmos.)||5111||SNPP VIIRS|
|VIIRS Collection 2 (L1, Land)||5200||NOAA-20 VIIRS|
|LTDR Collection 4||464||NOAA AVHRR|
|LTDR Collection 5||465||NOAA AVHRR|
|NACP Collection 4||404||Terra MODIS|
|SLSTR & OLCI Collection 1||450||Copernicus Sentinel SLSTR & OLCI|
|MERIS Collection 1||490||Envisat MERIS|
If users know the collection number and short-name of their desired products, it is straightforward to navigate through the online archive. For example, the following URL provides the location that lists all 240 6-minute datasets for the SNPP VIIRS Collection 1 (Archive Set 5110) Day-Night Band Geolocation products (VNP03DNB) for 2015, Day-Of-Year 004:
When downloading a dataset, it gives you the option to either open the file (by selecting Open with) with a particular image-handling software package or save it to your local system’s default Download directory. A couple of simple, open-source packages to visualize your downloaded products include Panoply and HDFView; You need to know the temporal frequency (e.g., 6-minute, Daily, 8-day, Monthly, etc.) of your preferred products to navigate to the correct location to find the listed data granules.
Scripts provide an efficient means to acquire multiple data products from the same collection/product, data-day, mixed collections/products, assorted data-days, etc. Common methods include wget and curl. Wget (for WWW get) is an open-source program from the GNU Project that is designed to help download content from web servers. Curl (for Client URL) is another open-source software that is used in command-line and scripts to transfer data using different network protocols. Consult LAADS Data Download Scripts for help, code samples, and additional information regarding creating and using download scripts.
Last updated: May 5, 2022