Blockchain technology has come to the public’s attention through the development of cryptocurrencies such as bitcoin. Blockchain technology, however, has other applications, where simultaneous change and sharing of information can update a block of data using a cryptographic security environment. It is an open and distributed design that allows real-time and simultaneous transactions.
For Earth observation and spatial technologies, only recently have researchers begun contemplating what might be useful in applying blockchain technologies. The European Space Agency has recently called for new ideas and applications of blockchain for Earth exploration. The European Union has recently funded projects that apply blockchain technologies to research, such as in sharing and simultaneous use of scientific data, where the European Space Agency looks to create ways in which information can be utilised across and between different institutions. Already in China, there have been developments of a protocol, based on the Consultative Committee for Space Data Systems (CCSDS) system, using the common format of TCF of sending data, to enable satellites to communicate and to share resources or apply communicative functions that do not repeat other satellites’ functions. This, effectively, means that such a blockchain-based protocol could allow satellites, including those not created using the same operating systems, to simultaneous work together using common data sharing and communication.
While Earth observation is one areas blockchain could have potential use, the medical field has already begun exploring blockchain for sharing and providing secure medical information about patients and provider data. Use of blockchain have included the application of crypto-spatial coordinate systems, with security of information sharing of location a key benefit of blockchain, that incorporates an immutable spatial context where time and spatial references are part of the record kept in a blockchain. The integration of blockchain with artificial intelligence (AI) has also allowed forecasting that can be used to assess patients and healthcare providers. Using a secure chain of historical movement data, AI can be used to identify healthcare needs based on daily activities.
Other fields have also begun to explore the use of blockchain, such as in land management. In this case, some applications have been used to assess how simultaneous accessible secure data can enable more efficient and real-time knowledge about parcels of land, including their tenure, vegetation, and seasonal change. However, so far, applications have been relatively limited and have not been fully explored for more complex applications.
One interesting application is something called littercoin, which is a type of blockchain application developed from OpenLitterMap using geospatial data on litter that is shared among a user group. Users simply upload data about plastic litter they spot where that data is then shared and edited by different users. The littercoin rewards users when they report the location of plastic litter in a location. Littercoin does not have a monetary reward but the intent is to eventually enable a monetary incentive for people to help keep their local area clean from plastic waste.
Blockchain has increasingly been a type of technology that many of us are becoming aware of. However, its application outside of cryptocurrencies is still relatively limited. This is the case with spatial technologies. Most application are experimental or based on narrow focus areas. Nevertheless, this might change as benefits are increasingly realised, such as in simultaneously sharing secure data and enabling communities of providers, such as in healthcare, to track sensitive information across time and space.
 For more on blockchain and how Europe is seeking further application of blockchain for Earth observation, see: https://eo4society.esa.int/2019/04/09/blockchain-and-earth-observation-a-white-paper/.
 For more on the use of blockchain for satellite communication, see: Ma, N., Wang, X., Li, Z., Zhan, P., He, X., Zhang, X., & Liu, Z. (2019). Design of Routing Incentive Protocol for Space Network Based on Blockchain Technology. In A. N. Shiryaev, Probability-2 (Vol. 95, pp. 123–131). https://doi.org/10.1007/978-981-13-6553-9_14.
 For more on healthcare application of blockchain and use of spatial technologies, see: Kamel Boulos, M. N., Wilson, J. T., & Clauson, K. A. (2018). Geospatial blockchain: promises, challenges, and scenarios in health and healthcare. International Journal of Health Geographics, 17(1), 25, s12942-018-0144–x. https://doi.org/10.1186/s12942-018-0144-x.
 For more on the use of blockchain in land management, see: Bennett, R. M., Pickering, M., & Sargent, J. (2019). Transformations, transitions, or tall tales? A global review of the uptake and impact of NoSQL, blockchain, and big data analytics on the land administration sector. Land Use Policy, 83, 435–448. https://doi.org/10.1016/j.landusepol.2019.02.016.
 For more on OpenLitterMap and littercoins, see: Lynch, S. (2018). OpenLitterMap.com – Open Data on Plastic Pollution with Blockchain Rewards (Littercoin). Open Geospatial Data, Software and Standards, 3(1), 6. https://doi.org/10.1186/s40965-018-0050-y.