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New research: Enabling coastal analytics at planetary scale

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Coastal science is evolving rapidly, driven by open satellite data, cloud platforms, and models that nowadays can achieve comparable resolutions for local and broad-scale studies. Altogether, this allows us to better understand and manage coastal risks at scales that were unimaginable just a decade ago. But while the resolution of the analyses increases, so does the challenge of managing, accessing, and analyzing these massive datasets efficiently.

At Deltares, we explored how cloud technology enables coastal analyses at scale. Our work introduces the Global Coastal Transect System (GCTS), a foundational dataset of over 11 million transects at 100-meter resolution that supports scalable coastal analytics and is excellent for regional comparisons. 

Our work aims to show that if the coastal community wants to address urgent challenges at scale—without sacrificing accuracy or resolution—it probably has to embrace cloud technology.

Key highlights from the study

  • Position: Addressing global coastal challenges requires scalable data repositories, tools and models
  • Foundational dataset: GCTS provides a global dataset of over 11 million coastal transects at 100-meter resolution, ideal for coastal analytics and regional comparisons.
  • Scalability: Cloud-native methods can map coastal waterlines at 50 kilometers per second—up to 700 times faster than traditional approaches—enabling high-resolution analyses that scale from local applications to broad-scale studies.
  • Critical findings: One-third of the world’s first kilometer of coastline lies below 5 meters—areas often vulnerable to accelerating sea-level rise—highlighting the need for climate adaptation planning. 
  • Next steps: As a community, we must work together to establish the foundations for scalable, transparent, and reusable coastal research.

Cloud technology to elevate coastal science 

Cloud technology already plays a critical role in modern science—particularly in fields that rely on large datasets such as satellite data catalogs. It is becoming equally crucial in coastal science as global flood maps and other coastal datasets are increasingly produced at resolutions previously reserved for local studies.

An essential component of this shift is using cloud-optimized data formats, such as Cloud-Optimised GeoTIFF (COG), (Geo)Parquet, and Zarr. These formats allow selective access to specific parts of a dataset, eliminating the need to download or load the entire file into memory. Like streaming a movie scene rather than downloading the entire film, cloud-optimised formats enable efficient access to large geospatial datasets.

The performance gains are substantial. In one of our benchmark tests, a common GIS task—retrieving data for a specific region of interest (e.g., the Basque Country)—took nearly 20 minutes using traditional formats like Shapefiles or GeoPackages. The same task was completed in under seven seconds with a cloud-native setup and could run on a much smaller computer. 

Cloud systems are also designed to scale. Instead of relying on a single computer, data is stored across vast networks of machines, enabling parallel access. Rather than pulling all the data through one narrow straw, cloud technology lets us use as many straws as needed—dramatically increasing throughput.

An equally important feature is data-proximate compute, which brings code to the data rather than vice versa. This minimises delays caused by data transfer and enables rapid processing directly where the data is stored.

Together, these two principles—cloud-optimised formats and data-proximate compute—make it possible to scale local methods to continental and even global domains, such as waterline mapping. In our study, this setup enabled us to map waterlines at 50 kilometers per second. Cloud-native workflows rely on metadata—structured summaries that describe the contents of a dataset—to streamline and optimise processing. Rather than loading entire files into memory, cloud systems use metadata to determine exactly which parts of the data are needed and when. It’s like scanning a table of contents before reading a book—knowing where to look before turning each page.

None of this is possible without standardised, well-structured data. While the broader cloud-native community has made significant progress in developing formats and protocols for scalable analysis, coastal science still needs to define standards that fit its specific needs. This is not just a technical task—it’s a shared responsibility. As a community, we must work together to establish the foundations for scalable, transparent, and reusable coastal research.

Global Coastal Transect System (GCTS): a foundational dataset for coastal analytics

This paper introduces the Global Coastal Transect System (GCTS), a novel foundational dataset comprising over 11 million coastal transects at 100-m resolution. Cross-shore coastal transects are essential to coastal monitoring, offering a consistent reference line to measure coastal change, while providing a robust foundation to map coastal characteristics and derive coastal statistics thereof. The transect system is computed in the UTM projection to avoid zonal bias that was present in earlier systems. The system also comes with administrative fields (continent, country, region), making it ideal for robust statistical regional comparisons.

Built with scalability in mind, the study uses GCTS as the foundation to analyze low-lying coastal regions across the world. The analysis combines GCTS, a vector dataset, with DeltaDTM, that is high-resolution elevation data stored in rasters. Typically integrating both data types at scale is challenging, but cloud-native changes the game. By using cloud-optimised data formats and organizing GCTS so that it is ideal for analytics (geospatial partitions),  the team achieved processing speeds up to 700 times faster than traditional methods. Our case study, about global coastal elevation shows that 33% of the world’s first kilometer of coastline lies below 5 meters—highlighting the vulnerability of coastal zones to sea-level rise and the pressing need for large-scale climate adaptation planning.

Access the Global Coastal Transect System (GCTS) data

While the data is available in a Zenodo repository for download, we highly recommend direct access via the cloud. The data is described in a STAC Collection part of the CoCliCo STAC catalog. For usage instructions, please see this tutorial or the documentation in the public TU Delft GitHub repository CoastPy—which also contains the codes used to conduct this analysis and much more! 

Read the full paper here:

Floris Reinier Calkoen, Arjen Pieter Luijendijk, Kilian Vos, Etiënne Kras, Fedor Baart, Enabling coastal analytics at planetary scale, Environmental Modelling & Software, Volume 183, 2025, 106257, ISSN 1364-8152, https://doi.org/10.1016/j.envsoft.2024.106257 

Abstract:

Coastal science has entered a new era of data-driven research, facilitated by satellite data and cloud computing. Despite its potential, the coastal community has yet to fully capitalise on these advancements due to a lack of tailored data, tools, and models. This paper demonstrates how cloud technology can advance coastal analytics at scale. We introduce GCTS, a novel foundational dataset comprising over 11 million coastal transects at 100-m resolution. Our experiments highlight the importance of cloud-optimised data formats, geospatial sorting, and metadata-driven data retrieval. By leveraging cloud technology, we achieve up to 700 times faster performance for tasks like coastal waterline mapping. A case study reveals that 33% of the world’s first kilometer of coast is below 5 m, with the entire analysis completed in a few hours. Our findings make a compelling case for the coastal community to start producing data, tools, and models suitable for scalable coastal analytics.

Keywords:

Coastal analytics; Cloud technology; Coastal change; Coastal monitoring; Satellite-derived shorelines; Low elevation coastal zone; Data management

This blog was written by Floris Calkoen (Deltares) and Jacinta Hamley (Vizzuality)

Publication: Comparing built-up area datasets to assess urban exposure to coastal hazards in Europe

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As coastal hazards rise with climate change, European cities face increasing exposure to flooding. A recent CoCliCo study published in Nature compares several built-up area datasets to assess this exposure and highlights the need for precise data in urban planning.

Information on urban land use beyond the urban-rural divide can enhance assessments of coastal hazards by refining damage estimates and supporting adaptation planning. However, inconsistent definitions of “urban” in past studies have resulted in varying exposure estimates. This study examines the exposed population and built-up area across four settlement types defined by different datasets.

Key Insights:

  1. Urban Vulnerability: The study compares datasets, revealing significant discrepancies in estimating urban areas at risk from coastal flooding.
  2. Data Accuracy: Precise data helps decision-makers better plan for future flood risks and enhances climate adaptation strategies.
  3. Resilience Planning: Comprehensive urban assessments help ensure European cities’ preparedness against rising sea levels and storm intensities.

Conclusion:

Our study highlights the critical importance of selecting the appropriate built-up area data for accurate population and exposure assessments. The choice of dataset can significantly affect estimates, with variations in population exposure reaching up to 65%(127 million people). This emphasises the need for careful consideration of dataset characteristics, including spatial resolution and classification thresholds, to ensure the data’s suitability for its intended purpose. Furthermore, refined urban classifications, beyond the simple urban-rural divide, are essential for more precise risk and damage assessments. Especially in rapidly growing suburban areas. Future research should explore more nuanced urban distinctions and assess the impacts of other contributing data variables to enhance the accuracy of exposure estimates.

To read the full study for more insights on adapting urban areas to coastal hazards in Europe click here.

Authors: Hedda Bonatz, Lena Reimann & Athanasios T. Vafeidis

Publication: Assessing Current Coastal Subsidence at Continental Scale: Insights From Europe Using the European Ground Motion Service

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Location of coastal flood plains in Europe as defined in this study

Land subsidence increases the risk of flooding in low-lying coastal zones by amplifying relative sea-level rise (SLR). In this study, the current coastal land subsidence at the scale of Europe is assessed for the first time using the new Copernicus European Ground Motion Service (EGMS), released in 2022. The results suggest that nearly half of the low-lying coastal areas in Europe are currently subsiding at a rate faster than 1 mm/yr on average!

Coastal subsidence is higher on average in areas with more people, urban centers, and critical infrastructure. This raises concerns that coastal subsidence—and therefore relative SLR—tends to be underestimated in Europe and presumably in many other regions around the world. This study demonstrates the utility of emerging continental-scale land motion services like EGMS in better characterising the issue, and anticipating coastal risks and adaptation needs accordingly.

Key Findings

  1. Challenges in VLM Calibration: The study compares the InSAR-based EGMS Ortho (Level 3) with nearby global navigation satellite systems (GNSS) vertical velocity estimates. It shows that the geodetic reference frame used to calibrate EGMS strongly influences coastal vertical land velocity estimates at the millimeter-per-year level. This calibration needs to be considered with caution.
  2. Adjusted Assessments of Coastal VLM: After adjusting the EGMS vertical velocity estimates to a more updated and accurate International Terrestrial Reference Frame (ITRF2014), an assessment of VLM in European low-elevation coastal flood plains (CFPs) was performed. The findings indicate that nearly half of the European CFP area is subsiding at a rate faster than 1 mm/yr on average.
  3. Urban and Harbor Vulnerabilities: The study reveals that urban areas and populations located in CFPs experience a near −1 mm/yr VLM on average (excluding the uplifting Fennoscandia region). For harbors, the average VLM is even larger, increasing to −1.5 mm/yr on average. This highlights the widespread importance of continental-scale assessments based on InSAR and GNSS to better identify areas at higher risk from relative SLR due to coastal subsidence.

Insights for Decision-Makers

  1. Impact on Flood-Prone Coastal Areas: The research shows that European flood-prone coastal cities subside on average at 1 mm/yr (Fennoscandia excluded). This is critical information for urban planning and coastal management in light of increasing SLR.
  2. Geocentric Reference Frame Considerations: The study underscores that the geocentric reference frame used to calibrate continental-scale land motion assessments significantly affects the results for geodetic (non-geophysical) reasons. This should be taken into account in future assessments.

Conclusion

Our study shows that there is a potential for a service for coastal adaptation practitioners, positioned downstream of EGMS or similar services in other regions worldwide. EGMS is a service of the “land” component of the European Earth Observation program Copernicus, but delivering actionable information to coastal users concerned with relative SLR requires additional analysis, as shown in this paper. Similar services can be developed in other regions of the world owing to the almost global coverage of the world’s coasts by the Sentinel 1 constellation of satellites. Given the challenges raised by SLR, it would be important to make sure that such operational services are further tailored to the needs of coastal practitioners concerned with understanding risks and planning for adaptation.

To read the full article click here.

Publication: The evolving landscape of sea-level rise science from 1990 to 2021

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As we navigate the challenges of climate change and environmental degradation, the health and sustainability of our floodplains are becoming increasingly crucial. A recent study, involving the efforts of the CoCliCo team and published in Nature Communications, sheds light on the alarming rate at which Europe’s floodplains are diminishing, presenting significant risks to both natural ecosystems and human societies.

The Critical State of Europe’s Floodplains

This groundbreaking research reveals a concerning trend in Europe’s floodplains. These vital ecosystems, which play a crucial role in maintaining biodiversity, regulating water cycles, and protecting against floods, are under threat due to intensified human activities and environmental neglect. The study quantitatively assesses the current state of Europe’s floodplains, highlighting the need for immediate and effective coastal risk management strategies.

Implications for Coastal Risk Management in Europe

The findings of this study are particularly relevant for coastal risk management in Europe. With the increasing frequency and severity of flooding events, understanding the dynamics of floodplains is essential for developing effective adaptation and mitigation strategies. This research not only highlights the challenges but also provides valuable insights for managing coastal risks, ensuring the safety of communities, and preserving natural ecosystems.

This will be crucial when providing context and information to develop and navigate the CoCliCo platform we’re building right now.

Strategies for Preserving Europe’s Floodplains

Drawing insights from the study, it is evident that a multifaceted approach is required to protect and restore Europe’s floodplains. This includes:

  • Enhancing Public Awareness and Engagement: Educating communities and stakeholders about the importance of floodplains, and involving them in conservation efforts.
  • Strengthening Environmental Policies and Regulations: Implementing robust policies that limit harmful activities and promote sustainable practices in floodplain areas.
  • Adopting Integrated Management Approaches: Coordinating efforts across different sectors and regions to ensure a holistic approach to floodplain management.

The way forward

The study serves as a crucial reminder of the interconnectedness of human actions and natural systems. It calls for an integrated approach, combining scientific research, policy-making, and community involvement to effectively manage and preserve Europe’s floodplains. This will not only mitigate the immediate risks associated with flooding but also contribute to the long-term health of our ecosystems and societies.

Conclusion

As highlighted in this important research supported by the CoCliCo project, addressing the challenges facing Europe’s floodplains is imperative for sustainable coastal management. By understanding the threats, acknowledging the value of these ecosystems, and taking concerted action, we can ensure a resilient and thriving future for Europe’s natural landscapes and the communities that depend on them.

For more detailed insights into this study and its implications for floodplain management, visit the research page on Nature Communications.