Beachmeter: an easy ArcGIS tool for quick, automated beach monitoring and change detection

What is it about?

Beaches are constantly changing as waves, wind, and storms move sand back and forth. These changes can happen in just a few days, yet many coastal management decisions—such as where to build protective structures or how to maintain tourist beaches—depend on understanding how the shoreline is shifting. Modern surveys collect huge amounts of detailed data with drones and airborne laser scanning, but it is difficult and time-consuming for coastal scientists and local authorities to analyse these measurements by hand, especially along many kilometres of coast. My publication presents Beachmeter, a free and open-source Python tool that works inside the widely used ArcGIS mapping software. Beachmeter reads digital elevation models (DEMs), which are three-dimensional maps of the land surface, from at least two different survey dates. It then automatically identifies the seaward and landward limits of the beach based on elevation values that can be adjusted for local conditions. The software quickly produces beach outlines, elevation models, and change maps, and it calculates key indicators such as beach width, area, and sediment volume. Because Beachmeter relies on elevation thresholds rather than manual drawing, it provides consistent and repeatable results that are often more precise than traditional cross-section surveys. Coastal managers can use it to detect erosion or accretion hotspots, track the effectiveness of nourishment projects, and plan responses to extreme storm events. Researchers can also adapt the method to a wide range of coasts worldwide.. In short, Beachmeter makes it practical to monitor multi-kilometre shorelines rapidly and objectively, helping communities protect infrastructure, tourism assets, and natural habitats from the impacts of coastal change.

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Photo by Secret Travel Guide on Unsplash

Photo by Secret Travel Guide on Unsplash

Why is it important?

Coastal communities face accelerating challenges from sea-level rise, stronger storms, and rapid shoreline change. Yet most official monitoring programs still rely on slow, labour-intensive field surveys along a few fixed profiles, leaving large stretches of coast unmeasured. At the same time, high-resolution digital elevation data from drones and airborne lidar are now collected at unprecedented frequency and scale. The key problem is not the lack of data, but the lack of practical tools to turn that data into timely, actionable information. Beachmeter fills this gap. It is the first freely available ArcGIS-compatible tool that automatically maps entire beaches and measures their width, area, and sand volume directly from elevation models. By using elevation thresholds rather than hand-drawn lines, it delivers consistent, repeatable results across multi-kilometre coastlines in minutes rather than days. Users can tailor the settings to local storm levels or tide conditions, making it applicable from tideless Baltic shores to other low-tide coasts worldwide. This combination of scientific rigor, open access, and ease of use allows government agencies, researchers, and consultants to detect erosion hotspots and evaluate nourishment projects before the next storm hits. In a time when rapid adaptation to climate-driven change is critical, Beachmeter turns abundant remote-sensing data into an immediate decision-making resource.

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