How to Search and Order Data with the LAADS “Find Data” interface
Before we begin:
- Make sure you have an Earthdata login before you start using the LAADS search and order interface.
- Log in to LAADS Web by selecting “Earthdata Login” under “Profile” in the top-right and provide your login credentials.
Now that you are logged in, open the LAADS Search and Order interface:
1 Select the data product(s) you need under Products.
All public LAADS products are available for selection via two drop-down menus: “All Sensors” and “All Searchable Collections.”
The first is a selection of all the source sensors or instruments whose data products are available. The second is the list of all the available data collections. In LAADS’ parlance, a collection equates to both a data processing version number and a unique set of data from a particular production cycle.
Selecting a particular sensor automatically reveals only the relevant collection(s) associated with that sensor. Based on your selection of sensor and collection, a table is presented with the short- and long-names of products that satisfy your chosen sensor-collection criteria. Each product has an info glyph or icon to its right, which is a link to detailed information for that product.
2 Select the temporal resolution.
You can either define (via drop-down selections) a single date or a date range for your temporal search window. Under the +Advanced link, users may also define single date(s) and time(s) or date ranges without the time component.
3 Select the data location.
You can define your geographic search window in several ways:
- Select or manually define your horizontal and vertical tile addresses (e.g., H08 V05)
- Draw your own custom-defined polygon
- Manually enter the latitude/longitude coordinates defining your search-space
- Select by country
- Select by a variety of validation sites
4 Generate the product files.
FILES will initiate the search and return data granules that meet the selected criteria. The search results are returned in a table that include the following columns:
Filename | Info| Product (collection) | Image | Date/Time | Download
- Filename: The filename with short-name, acquisition year and day, time, tile address, collection number, production year, date, and time, and format suffix
(For details, check: https://go.nasa.gov/3dKEhIH )
- Info: The Info button provides several file-level details for each granule including file name, file size, checksum, etc. A checksum is a specific numeric value that is derived from a digital data object (such as a data file), which helps detect errors that may have occurred during data transmission or storage. Users can run a checksum on their acquired files to match with the published (checksum) values to verify the data integrity.
- Product (collection): Product short-name and collection number in parenthesis.
- Image: Browse image for the dataset, if applicable. Not all products have supported browse images.
- Date/Time: The defined date and time.
- Download: Direct download link that also indicates the file size in megabytes (MB).
You may select one, more, or all files, and click REVIEW & ORDER.
5 Review and order the selected data products.
This page offers users several options that may vary with each product:
- Apply post-processing: Post-processing may include many data transformation options such as parameter subsetting to deliver only those Science Data Set (SDS) variables that you require, spatial subsetting to reduce the geographic footprint, format conversion, resampling, etc. Offered post-processing options vary with each product type. Some post-processing examples are below.
- Select only the data sets that you want from a file. Most LAADS products contain many data sets (some contain thousands of data sets). If you will not need most of them, choose only the ones you will use. This can reduce the size and number of files you will need to download.
- Select only the data from the geographic region you specify. Even if you searched for data from only a specific region in step (3), the files can contain more data, with only some of it actually intersecting the region you specified. By selecting this option, we will slice out all data that are not in your specified region. This can further reduce the size of files you will need to download and will also reduce the amount of data you need to process.
- This option can combine the data from multiple files into one file, with all the data correctly geolocated. Some caveats:
- All combined files will be from the same date (for lists of files from multiple dates, there will be a result file for each separate date).
- Data sets remain separate – our tool does not combine data from different data sets together.
- Where files overlap geographically, we will favor pixels based on whether the pixel contains a measurement value or not, and then favor the pixel nearest to the satellite's nadir position.
- Change the format of the file. Currently, we offer the GeoTIFF file format, commonly used in Geographic Information System (GIS) tools.
- Change the Map Projection or Sample Size. Many maps and data sets from other instruments do not use the Geographic, or Cartesian, coordinate system. When overlaying data sets, they will line up better if they use the same coordinate system. The Reproject option allows one to specify parameters that govern the reproject operation. Refer to the U.S. Geological Survey Professional Paper 1395, "Map Projections – A Working Manual", U.S. Government Printing Office, Washington: (C)1987, for detailed information on map projections.
- Include process log files with the output. Most users will not find this option particularly useful.
- Select delivery method: You can select a delivery method, the default being “Pull” and hit the “Submit Order” button. Once your order is processed and ready, you are notified by e-mail with details on how to download your ordered data products.
- Manage your orders: You can access your User Profile (the last link called “Past Orders” on the left-side in the search and order interface) to check the status of your order, resubmit a previously submitted order, cancel an order, etc.
*Keep in mind that if your search criteria identify more than 2000 files, no results are returned; instead, you are asked to revise your search criteria.
Last updated: November 12, 2021