Earth Extractor

Earth Extractor simplifies the workflow of data acquisition from multiple satellite data providers. The library is designed to be used as a command line tool, but can also be used as a library.

Unlike other projects, Earth Extractor is designed to simplify the data acquisition process for a select amount of satellite providers and is deliberately written to provide a hands-off approach for simple data collection. This is dissimilar to projects such as EODag and getSpatialData which aim to harmonise the process over many providers and satellite types.

The library creates a framework around providers and satellites, allowing a satellite to have separate providers for querying and downloading. This provides the benefit of searching with an API allowing more comprehensive filters than those that are available in the download provider. For example, the Copernicus Data Space allows cloud coverage filters, but for Sentinel 1, the data is better served by the Alaskan Satellite Facility which does not offer such filters.

Changelog

Semantic version changes are tracked in the CHANGELOG.

Getting started

Installation

Install from PyPI

In your local environment, install the package with:

pip install earth-extractor

The package repository can be found at PyPI: earth-extractor.

Install from git (development)

If poetry is not installed locally, install it first with:

pip install poetry

Then clone the repository and install the package dependencies with:

git clone https://github.com/eceo-epfl/earth-extractor
cd earth-extractor
poetry install

Define user credentials

There are two methods to store the provider secrets required to access the data:

1. System keyring (recommended)
2. .env file

Option 1: System keyring (recommended)

This method requires that your operating system has a secret keyring installed. This is usually the case, but if you're operating a server linux installation, or using WSL on Windows, for example, one may not exist. In this case, you can use the .env file method.

User credentials are managed by the keyring library which make use of your operating system's secret keyring. The credentials are stored in the system and are retrieved by the library when required.

In order to define them, use the following command:

earth-extractor credentials --set

Option 2: .env file

In the folder you are working in, place an .env file with the keys and values as follows (the necessary keys can be found in the credential sources section underneath):

COPERNICUS_USERNAME=
COPERNICUS_PASSWORD=
NASA_TOKEN=

Credential sources

Credentials can be obtained from the respective providers:

• Copernicus Data Space

  • COPERNICUS_USERNAME and COPERNICUS_PASSWORD

• Alaskan Satellite Facility and NASA LAADS repository

  • NASA_TOKEN
  • Obtain the token by registering first at NASA EarthData, and then in My Profile, select Generate Token from the top menu and GENERATE TOKEN from the bottom of the page.
  • Make sure to accept the Alaskan Satellite Facility EULA after registering in NASA Earth Data: Accept New EULAs

Example usage (CLI)

Sentinel 1

Search for Sentinel-1 L1 data for Switzerland between the dates 2022-11-19 and 2022-11-29.

earth-extractor batch \
    --roi 45.81,5.95,47.81,10.5 \
    --start 2022-11-19 --end 2022-11-29 \
    --satellite SENTINEL1:L1

SwissImage

Search and download SwissImage 0.1m and 2.0m resolution data for a 200 metre buffered region around longitude: 7.35999° and latitude: 46.22457° between the dates 2022-11-19 and 2022-11-29.

Note: In this example the download will start without user intervention, by using the --no-confirmation flag. We can also see the first use of multiple satellites in the same query (although SwissImage is not technically a "satellite" product).

earth-extractor batch \
    --start 2020-10-06 --end 2023-01-01 \
    --roi 7.35999,46.22457 --buffer 200 \
    --satellite swissimage:cm200 \
    --satellite swissimage:cm10 \
    --no-confirmation

MODIS and VIIRS

Search for VIIRS (L1) and MODIS Terra (L1B) data with a 2km buffered region around longitude: 7.35999° and latitude: 46.22457° between the dates 2022-10-06 and 2023-01-01.

earth-extractor batch \
    --start 2022-10-06 --end 2022-10-07 \
    --roi 7.35999,46.22457 --buffer 2000 \
    --satellite VIIRS:L1 \
    --satellite MODIS_TERRA:L1B \
    --no-confirmation

Technical specifications

Components

Satellites and providers

The following satellites and respective processing levels are included in the design:

Satellite	Levels	Search provider	Download provider
Sentinel-1	1 (GRD)	Copernicus Data Space	Alaskan Satellite Facility
	2 (GRD_SIGMA0)	Copernicus Data Space	Copernicus Data Space
Sentinel-2	1C	Copernicus Data Space	Copernicus Data Space
	2A	Copernicus Data Space	Copernicus Data Space
Sentinel-3	1B	Copernicus Data Space	Copernicus Data Space
	2	Copernicus Data Space	Copernicus Data Space
	3 LFR Atmos (Land)	Copernicus Data Space	Copernicus Data Space
	3 WFR Atmos (Water)	Copernicus Data Space	Copernicus Data Space
MODIS Terra	1B	NASA Common Metadata Repository	NASA LAADS
MODIS Aqua	1B	NASA Common Metadata Repository	NASA LAADS
VIIRS	1	NASA Common Metadata Repository	NASA LAADS