Earth observation and remote sensing are key branches of science that employ satellite data to monitor and comprehend the Earth and its surroundings. However, many researchers and consumers find it difficult to get and use satellite imagery due to a variety of reasons such as cost, availability, quality, and complexity. In recent years, the number of people outside the EO community who try to work with satellite data has increased. They can be journalists, teachers, scientists from another domain, students or just interested people.
The Earth is in our hands and so the data must be too. The data is needed fight the climate crisis. To monitor, understand, and help our planet and thus help ourselves. In this blog post, I will have a look at the accessibility and cost of satellite images, as well as what the community requests and proposes to better the situation.
The accessibility and cost of satellite imagery depend on several factors, such as:
The type of satellite mission: public or commercial, optical or microwave, low or high resolution, etc.
The data policy of the satellite operator: free or fee-based, open or restricted, online or offline, etc.
The data processing level: raw or calibrated, georeferenced or orthorectified, etc.
The data distribution platform: web portal, FTP server, cloud service, etc.
The data analysis tools: software, algorithms, models, etc.
The number of papers and citations citing Earth observation (EO) satellites is expanding exponentially, according to a review by Zhao et al. (2022), showing a high demand and interest in satellite data. However, the analysis discovered that some EO satellite missions are losing favour due to limited accessibility or obsolete technology. AVHRR, SPOT, and TerraSAR, for example, are losing ground to newer missions such as Landsat, Sentinel, MODIS, Gaofen, and WorldView.
For journalists, satellite imagery is a powerful tool for discovering and analysing events and providing vivid illustrations. There is real potential for investigative journalism to make greater use of these space images, for example in reporting on conflicts, climate change, refugees, forest fires, illegal mining, oil spills, deforestation, slavery, and many other issues.
Although I believe journalists should focus on researching and authoring their story, and get experts to help with the technical work, working with Earth observation data and getting to know it better can help and inspire them. The Global Investigative Journalism Network (GIJN) has put together an article on resources for journalists to get started.
A study, by Dubovik et al. (2021), revealed some major issues in satellite remote sensing that the community must address. One of these difficulties is to make satellite data more accessible and usable by providing better user-friendly platforms, tools, and standards. The study also emphasised the importance of increased interdisciplinary collaboration and communication among satellite data users and stakeholders.
Requests and Proposals
The Earth observation and remote sensing community has expressed various requests and proposals to improve the accessibility and cost of satellite imagery. Some of these are:
To increase the availability and diversity of free and open satellite data, especially for developing countries and regions that lack adequate resources or infrastructure to access commercial or restricted data. (Innovations in satellite measurements for development (worldbank.org))
To reduce the cost and complexity of acquiring and processing high-resolution satellite data, especially for applications that require fine-scale spatial or temporal information. (Open High-Resolution Satellite Imagery: The WorldStrat Dataset -- With Application to Super-Resolution (arxiv.org))
To enhance the quality and consistency of satellite data products, especially for long-term monitoring or trend analysis that require accurate calibration and validation. (Assessing the role and consistency of satellite observation products in global physical–biogeochemical ocean reanalysis)
To develop more advanced and robust methods and tools for analyzing satellite data, especially for applications that involve complex phenomena or processes that require physical or mathematical modeling. (An Introduction to the Spatio-Temporal Analysis of Satellite Remote Sensing Data for Geostatisticians | SpringerLink)
To promote more education and training on satellite data usage, especially for users who lack sufficient background knowledge or skills in remote sensing or geospatial analysis. (ESA - Education & training, EO training & education - eo science for society (esa.int))
To foster more collaboration and exchange among satellite data providers, users, and researchers, especially for sharing best practices, experiences, feedbacks, or innovations. (Earthdata Cloud Evolution | Earthdata (nasa.gov))
Also, the article Grand Challenges in Satellite Remote Sensing reviews the achievements and challenges of satellite remote sensing of the Earth’s atmosphere, land, and ocean in the past five decades and discusses the future directions and opportunities for improving the quality and value of satellite data.
There are already initiatives to provide data free of charge and to make the access as easy as possible. Open access initiatives like NASA's Earth Science Data Systems (ESDS) Program and the Copernicus program exemplify this commitment to accessibility. The Copernicus programme is a joint initiative of ESA and the European Commission that provides operational information on the state of the environment through a network of satellites (Sentinel), ground stations (in situ), services (land, marine, atmosphere, climate change, emergency management, security), and users. However, obtaining high-resolution optical and SAR data is often costly, and in situ data are also rarely shared publicly with the community.
Another community-driven initiative which aims to ease the access to EO data is the OpenSpaceData. The goal of OpenSpaceData is not to provide a full solution for satellite data analysis, but rather to offer an entry point for first-time users and to educate them on how to use the data for their own purposes.
OpenSpaceData is a tool that allows users to access and analyse satellite data without any technical or professional knowledge. Users only need to specify what they want to analyse, which location or area they are interested in, and which time period they want to examine. The tool then provides them with the best possible satellite image and step-by-step instructions on how to use the data and derive insights from it. The goal of OpenSpaceData is not to provide a full solution for satellite data analysis, but rather to offer an entry point for first-time users and to educate them on how to use the data for their own purposes.
The tool was developed as a prototype, but I like the concept of guiding even inexperienced users through the entire process. I see possibilities to further improve it. For example, the steps for processing the image data could be included in a wizard in applications like QGIS or SNAP. I can also recommend reading the article Outer Space for All! Just How Accessible Is ESA's Satellite Data? by Niklas Jordan (@email@example.com - Mastodon). His article covers other facets of the topic. Niklas is also one of the developers of OpenSpaceData.
Privateer, a company co-founded by Steve Wozniak, aims to change that accessing and processing satellite data is often costly, complex, and exclusive by creating a data ride-sharing economy for space.
Privateer's main mission is to provide space situational awareness: creating the "Google Maps of space" for satellite mission planning and orbital debris tracking. Its first product, Wayfinder, offers such tracking for spacecraft and other objects in space. Wayfinder uses proprietary knowledge graph technology to collect and process information about space objects, enabling space operators to manoeuvre safely and effectively. It is also launching a new module for satellite operators called Pono, which will help make space data available at scale and at a far lower cost than it is today. Pono will allow customers to "ride-share" on satellites and task them to collect data on whatever region of Earth is of interest.
Privateer's vision is to democratise and ease the access to satellite data, making it available to anyone who needs it.
Another platform that aims to democratise and ease access to satellite data is Sentinel Hub. It is a cloud-based service that allows users to browse, process, and analyse satellite imagery from various sources, such as Sentinel, Landsat, MODIS, and more. Sentinel Hub provides a user-friendly interface, a powerful API, and a set of tools for creating custom applications and workflows. Sentinel Hub enables users to access satellite data in real-time, perform complex analyses, and visualise the results in different formats. Sentinel Hub also offers a free educational account for students and teachers, as well as a playground for experimenting with satellite data. By lowering the barriers to entry and providing flexible options, Sentinel Hub makes satellite data more accessible and useful for a wide range of users and purposes.
Satellite imagery is a valuable source of information for Earth observation and remote sensing, and therefore a key factor in addressing the climate crisis. However, accessing and using satellite imagery can be challenging for many users due to several factors such as cost, availability, quality, and complexity. The earth is in our hands, so the data must be too! Knowledge is the prerequisite for action. I'm not saying that everything must be free, but prices should be within a reasonable range. They could be offered more cheaply for research and journalism than for purely commercial use.
What are the most main challenges you face when working with data? What action should be taken either by the major agencies, governments, or the community to improve the situation?
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