Alaska Satellite Facility
Delivering Remote Sensing Data Since 1991

Get Interferograms from ASF

There are many ways to access Sentinel-1 interferograms for users comfortable working at the command line. Below are steps and options to explore.


Find Interferograms via the CMR Search API

Sentinel-1 Interferogram (BETA) products are integrated with the ESDIS Common Metadata Repository (CMR), and are searchable via the CMR Search API. Visit the CMR Search API documentation for details and available search parameters.

The CMR collection concept IDs for Sentinel-1 Interferogram (BETA) products are:

  • C1379535891-ASF — Sentinel-1 All Interferometric Products (BETA)
  • C1379522387-ASF — Sentinel-1 Full Resolution Wrapped Interferogram and DEM (BETA)
  • C1379535600-ASF — Sentinel-1 Unwrapped Interferogram and Coherence Map (BETA)

For example, this search returns a list of all "Sentinel-1 All Interferometric Products (BETA)" products over Pasadena, CA since Jan 1, 2018:

https://cmr.earthdata.nasa.gov/search/granules.csv?collection_concept_id=C1379535891-ASF&temporal=2018-01-01T00:00:00Z,&point=-118.1445,34.1478&page_size=50

The download URL for each product can be extracted from CMR search results and downloaded via command line tools like cURL and Wget.


Get Interferograms via cURL and Wget

Visit How To Access Data With cURL and Wget for instructions on downloading products with cURL and Wget, including how to provide your Earthdata Login credentials via a .netrc file.


Get Interferograms via AWS CLI, Boto 3, and GDAL

Sentinel-1 Interferogram (BETA) products are stored in Amazon Web Services' Simple Storage Service (AWS S3). In addition to obtaining files via HTTP download, ASF makes these products available for download via AWS tools such as the AWS CLI, the Python Boto 3 library, and GDAL's vsis3 utility.

Configuring Temporary Security Credentials

Users can obtain a temporary AWS access key from ASF using their Earthdata Login credentials. The temporary key is then used to obtain data while the access key is valid. Temporary access keys are obtained by invoking the following URL: https://grfn.asf.alaska.edu/door/credentials

Enter your Earthdata Login credentials when prompted. If accessing via cURL or Wget, you can provide your credentials via a .netrc file as described at How To Access Data With cURL and Wget.

The "Credentials" block of the response includes an Access Key, Secret Key, and Session Token for a temporary S3 session, along with the session's expiration date. The "PolicyDocument" block describes the AWS permissions granted for the session, including the name of the S3 bucket where Sentinel-1 Interferogram (BETA) products are stored.

Authentication for the AWS CLI and other tools can be configured by setting the following environment variables:

$ export AWS_ACCESS_KEY_ID=ASIAIXR2XDAYKFSAE2VQ
$ export AWS_SECRET_ACCESS_KEY=heAgBidhHAjEhRrtxCItpvJYQF8qMQVIaWSvF1qS
$ export AWS_SESSION_TOKEN=FQoDYXdzEGMaDAcgUNixqCXpy...<remainder of security token>

 This python script is an example of requesting credentials and formatting the necessary export commands.

Using the Tools

Below are details describing how to use AWS Command Line Interface (CLI), Boto 3, and GDAL.


Get Interferograms from Long-Term Storage

Sentinel-1 Interferogram (BETA) products older than 60 days may be transitioned to long-term storage. Files in long-term storage are not immediately available for download.

The storage status of a file (available, archived, or retrieving) can be checked by invoking https://grfn.asf.alaska.edu/door/status/<file_name> :

$ wget -O- -q https://grfn.asf.alaska.edu/door/status/S1-IFG_RM_M1S1_TN100_20180112T133507-20171231T133440_s1-resorb-697d-v1.1.3-standard.zip
{
  "status": "archived"
}

Invoking the download URL for archived products will initiate the retrieval process and return a HTTP 202 ACCEPTED response:

$ wget -O- -q https://grfn.asf.alaska.edu/door/download/S1-IFG_RM_M1S1_TN100_20180112T133507-20171231T133440_s1-resorb-697d-v1.1.3-standard.zip
Your requested data are being fetched from long-term storage.  Please try again later.

$ wget -O- -q https://grfn.asf.alaska.edu/door/status/S1-IFG_RM_M1S1_TN100_20180112T133507-20171231T133440_s1-resorb-697d-v1.1.3-standard.zip
{
  "status": "retrieving"
}

The status URL can be monitored until the file's status transitions to "available". This usually takes a few minutes, but can take several hours when requesting a large number of files.

$ wget -O- -q https://grfn.asf.alaska.edu/door/status/S1-IFG_RM_M1S1_TN100_20180112T133507-20171231T133440_s1-resorb-697d-v1.1.3-standard.zip
{
  "status": "available",
  "expiration_date": "2018-05-02 00:00:00"
}

Files with a status of “available” are immediately available for download via their download URL.

 This python script is an example of using these tools to download a file from long-term storage.


Get SAR Data

Get SAR Data

Select and download SAR data online using Vertex.

Use the ASF API for downloading SAR data via a command line.