3. Results and Thematic Synthesis
3.1. Evidence Base and Organizing Domains
The review process shown in
Figure 1 resulted in a final evidence base of 30 studies and official documentation sources. These sources show that AI-enabled remote sensing is being applied across a wide range of coastal and environmental domains. The evidence base includes review articles, empirical remote-sensing applications, machine-learning method papers, official data-source documentation, and policy-relevant climate assessment reports. Together, these studies indicate that the field is moving from isolated image classification toward integrated, multi-sensor, and decision-oriented workflows.
Five domains organize the synthesis: shoreline extraction and erosion monitoring; coastal flooding, storm surge, overtopping, and susceptibility mapping; mangrove, wetland, and coastal ecosystem monitoring; land-cover change and coastal urbanization; and GIS-based decision support for adaptation planning. These domains overlap. For example, shoreline extraction may support erosion risk assessment, while mangrove monitoring may inform nature-based flood protection and blue-carbon policy.
Figure 2 visualizes the thematic structure used to organize the synthesis.
3.2. Earth Observation Data Infrastructure
Coastal AI applications depend on a multi-sensor data ecosystem. Sentinel-1 provides C-band synthetic aperture radar observations that support day-and-night, all-weather imaging, making it valuable for flood mapping, inundation monitoring, wetland water dynamics, and storm impact assessment [
12]. Sentinel-2 provides multispectral imagery across 13 spectral bands at spatial resolutions of 10 m, 20 m, and 60 m, making it central to shoreline, vegetation, water, and land-cover applications [
13]. Landsat 8/9 provides a long-running, globally consistent archive through OLI/TIRS products, enabling multi-decadal coastal change analysis [
14]. MODIS provides broad, frequent observations across 36 spectral channels and supports global environmental monitoring, including vegetation, land-cover, ocean, and natural hazard applications [
15].
Data selection is application-specific. Sentinel-2 and Landsat are widely used for optical shoreline and land-cover mapping, but they are affected by clouds, shadows, turbidity, mixed pixels, and tidal-stage variation. Sentinel-1 SAR is useful in cloudy or storm-prone regions, but speckle, geometric distortions, and specialized preprocessing requirements can complicate interpretation. UAV imagery and LiDAR provide high-resolution validation and local detail, but their spatial coverage, cost, permitting requirements, and processing burden can limit routine application.
Table 3 summarizes the main values and limitations of common Earth observation sources used in coastal AI workflows.
Data interoperability remains a major challenge. AI workflows often require co-registration of sensors with different spatial resolutions, temporal frequencies, viewing geometries, and radiometric properties. Without careful harmonization, models can learn artifacts rather than environmental patterns. Publication-quality studies should therefore report sensor products, acquisition dates, preprocessing steps, tidal controls, class definitions, training and validation splits, and uncertainty measures. These details are not secondary. They determine whether model outputs can be compared across sites, repeated by other teams, and trusted by coastal managers.
3.3. AI and Machine Learning Method Families
The reviewed literature uses three broad families of methods. The first is classical ML, including Random Forest, support vector machines, decision trees, logistic regression, and gradient boosting. Random Forest remains popular because it handles nonlinear relationships, mixed predictors, and relatively small training datasets while providing feature-importance measures [
16]. XGBoost and related boosting methods are useful for structured geospatial variables and susceptibility mapping because they learn sequential corrections that improve predictive performance [
17].
The second family is deep learning for imagery and time series. CNNs, U-Net, DeepLab-style architectures, residual U-Nets, recurrent models, and edge-aware models are used for semantic segmentation of shorelines, water-land boundaries, land cover, and mangrove extent. U-Net remains influential because its encoder-decoder structure preserves localization while capturing contextual information [
18]. Deep learning has become central in remote sensing because it can learn spatial features directly from imagery and can exploit large satellite archives when training labels are sufficient [
19]. Shamsolmoali et al. demonstrated a deep U-Net structure for sea-land segmentation in remote sensing imagery [
20], and BDCN_UNet extended shoreline extraction through deep learning and edge-aware boundary logic [
21].
The third family is hybrid and explainable modeling. Hybrid AI-GIS systems combine model outputs with spatial decision layers, exposure data, infrastructure networks, and planning zones. Recent domain applications include deep learning for mangrove monitoring [
22], machine-learning-based shoreline change prediction [
23], remote-sensing-integrated flood susceptibility mapping [
24,
25,
26], hydrological flood prediction [
27], and explainability methods such as SHAP [
28]. These hybrid systems are strongest when they combine classification or prediction with external validation, domain knowledge, uncertainty communication, and decision thresholds.
Table 4.
AI methods, outputs, and validation requirements for coastal resilience applications.
Table 4.
AI methods, outputs, and validation requirements for coastal resilience applications.
| Application Domain |
Common Methods |
Typical Outputs |
Publication-Quality Validation Needs |
| Shoreline extraction and erosion |
CNN, U-Net, BDCN_UNet, residual U-Net, edge detection, Random Forest, object-based classification. |
Water-land boundary, shoreline displacement, erosion/accretion rates, change maps. |
Independent shoreline labels, GNSS/UAV/LiDAR validation, boundary-distance metrics, tidal-stage reporting, cross-region tests. |
| Flood susceptibility and inundation |
Random Forest, XGBoost, SVM, gradient boosting, AdaBoost, deep learning, hydrological AI. |
Hazard zones, susceptibility classes, inundation maps, predictor importance. |
Event-based validation, independent flood inventory, AUC/F1 plus uncertainty, temporal holdout, operational thresholds. |
| Mangrove, wetland, and habitat monitoring |
Random Forest, SVM, CNN, U-Net, vegetation-index fusion, time-series classification, SAR-optical fusion. |
Habitat extent, change maps, health indicators, restoration progress, carbon-relevant indicators. |
Field plots, UAV imagery, expert labels, class-balanced reporting, species or structure validation. |
| Land-cover and coastal urbanization |
Random Forest, gradient boosting, CNNs, change detection, transformers, time-series segmentation. |
Urban expansion, impervious surface, vegetation loss, land-use transition maps. |
Cross-region validation, confusion matrices, class-specific precision/recall, and socioeconomic context. |
| GIS decision support |
AI-GIS integration, spatial MCDA, dashboards, digital twins, scenario modeling. |
Adaptation priorities, early warning products, restoration suitability, exposure-vulnerability layers. |
Stakeholder validation, interpretability, uncertainty communication, update schedule, and governance documentation. |
3.4. Shoreline Extraction and Coastal Erosion Monitoring
Shoreline extraction is one of the most active coastal AI applications because shoreline position is a key indicator for erosion, accretion, storm impact, sediment dynamics, and coastal hazard exposure. Traditional methods use water indices, thresholding, edge detection, object-based image analysis, and supervised classification. These approaches can be efficient, but they are sensitive to turbidity, vegetation, foam, wet sand, shadows, tidal stage, wave runup, and image resolution. Deep learning segmentation models attempt to reduce manual rule-setting by learning features directly from training labels.
Recent reviews highlight the expansion of deep learning for coastal boundary extraction and erosion monitoring. Blais and Akhloufi synthesize advances in remote sensing and deep learning to extract coastal boundaries [
3]. Christofi et al. review open remote sensing data, GIS, AI, UAV support, and ground truth for shoreline detection and erosion monitoring, emphasizing Sentinel-2 and Landsat 8/9 as core open-access datasets [
4]. BDCN_UNet illustrates the shift toward specialized architecture for coastal boundaries by combining semantic segmentation and edge-aware logic [
21]. Osondu et al. illustrate the growing use of machine learning for shoreline change prediction and erosion analysis in a coastal case-study setting [
23].
The strongest shoreline studies go beyond single-site accuracy. They specify shoreline definitions, control or document tide and wave conditions, report boundary-distance errors, compare optical and SAR performance, and test transferability to different geomorphic settings. A model trained on sandy beaches may not transfer to mangrove shorelines, rocky coasts, tidal flats, deltas, coral islands, or urban seawalls. Publication-quality shoreline AI work should therefore report both pixel-level accuracy and boundary-location error in terms meaningful to coastal managers. For planning, a boundary error of a few meters may matter more than a high image-wide accuracy score because the shoreline itself can occupy only a small portion of the image.
A major limitation in this domain is the mismatch between image segmentation and coastal geomorphology. Many algorithms treat the shoreline as an instantaneous water-land boundary. Still, coastal management often relies on geomorphic proxies such as dune toe, vegetation line, high-water line, wet-dry boundary, cliff edge, or seawall alignment. Future shoreline AI systems should state the proxy being extracted, relate it to the management decision, and avoid treating all coastal boundaries as equivalent. This is especially important in low-slope tidal flats and wetlands, where tidal stage can shift the apparent waterline substantially between images.
3.5. Coastal Flooding, Storm Surge, Overtopping, and Hazard Susceptibility
AI contributes to coastal flooding and hazard research through susceptibility mapping, short-term prediction, event detection, and post-disaster mapping. Machine learning models commonly combine flood inventories with elevation, slope, drainage density, rainfall, soil, land cover, distance to river or coast, and SAR-derived inundation information. Such workflows can generate spatially explicit hazard layers that support planning, insurance, emergency management, and infrastructure prioritization.
Recent studies and reviews demonstrate both promise and caution. Duiker et al. review machine learning for coastal flooding and overtopping, identifying trends, data sources, and prospects [
5]. Hajji et al. integrate remote sensing, machine learning, Google Earth Engine, and explainability for flood prediction [
24]. Islam et al. synthesize urban flood susceptibility mapping across remote sensing, machine learning, and other modeling approaches [
25]. Feizbahr et al. demonstrate flood susceptibility mapping using machine learning and the geospatial integration of Sentinel-1 SAR data to enhance early warning [
26]. In hydrological forecasting, Nearing et al. show that AI can improve access to extreme flood predictions in ungauged watersheds [
27].
Despite these advances, operational flood warning requires more than a high AUC. It requires near-real-time data ingestion, reliable exposure layers, threshold design, uncertainty communication, emergency protocols, institutional trust, and mechanisms for communicating warnings to vulnerable communities. Retrospective susceptibility models can be valuable for planning, but they should not be presented as operational early-warning systems unless they have been tested under real-time conditions. The review, therefore, distinguishes susceptibility mapping from operational flood forecasting. The former identifies areas likely to flood under plausible conditions; the latter must issue timely warnings as hazards evolve.
The flood domain also illustrates the need to connect AI with knowledge of physical processes. Coastal flooding often results from compound interactions among rainfall, river discharge, storm surge, astronomical tide, waves, drainage capacity, and land subsidence. Purely data-driven models may capture correlations in past events, but they can fail when future events fall outside the range of the observed training data. Hybrid systems that combine remote sensing, hydrodynamic simulation, elevation correction, and machine learning are better positioned to support decision-making under nonstationary climate conditions.
3.6. Mangrove, Wetland, and Coastal Ecosystem Monitoring
Coastal ecosystems such as mangroves, salt marshes, seagrass beds, tidal flats, and wetlands are central to environmental sustainability because they support biodiversity, fisheries, carbon storage, water quality, shoreline stabilization, and storm-surge attenuation. Remote sensing is essential for monitoring these ecosystems because field access can be difficult, spatial extent can be large, and change can occur through both natural and anthropogenic pressures.
Verified mangrove and wetland sources show the diversity of methods in this domain. Xu et al. present a deep learning model for mangrove monitoring in the Indus Delta [
22]. Sunkur et al. review mangrove mapping and monitoring with remote sensing for climate-change resilience [
6]. Rondon et al. provide a systematic review of remote sensing-based assessments of mangrove ecosystems in Gulf Cooperation Council countries [
7]. Cazzetta et al. synthesize AI tools for ecological research and monitoring in transitional water ecosystems [
8]. These sources show that AI can improve mapping consistency, but they also show that ecological interpretation requires more than spectral classification.
Mangrove and wetland mapping illustrates the need for multi-sensor approaches. Optical imagery and vegetation indices such as NDVI, EVI, SAVI, NDWI, and red-edge bands are useful. Still, mangrove signatures can be mistaken for other vegetation or obscured by tidal inundation. SAR adds structural and moisture sensitivity, while UAVs and LiDAR improve local validation and canopy-structure assessment. Field labels and local ecological knowledge remain essential because spectral separability does not automatically equal ecological validity.
For environmental sustainability, the most valuable ecosystem products are not only binary maps of presence and absence. Managers need change trajectories, restoration success indicators, degradation alerts, fragmentation measures, canopy condition, hydrological connectivity, and carbon-relevant proxies. AI can support these outputs when the training data are ecologically meaningful and when validation distinguishes between map accuracy and ecological validity. A model may accurately identify green vegetation but still fail to identify mangrove species composition, canopy age, hydrological stress, or restoration performance.
3.7. Land-Cover Change and Coastal Urbanization
Coastal urbanization changes exposure, runoff, habitat connectivity, sediment supply, and the social geography of risk. Remote sensing has long supported land-cover change analysis, but AI expands this capacity by improving classification of heterogeneous urban edges, impervious surfaces, vegetation transitions, and informal development. AI-enabled land-cover monitoring can support zoning, green infrastructure planning, wetland protection, evacuation-route assessment, and post-disaster recovery analysis.
Land-cover and urbanization applications often use multi-temporal optical imagery, SAR backscatter, vegetation indices, built-up indices, night-time lights, road networks, population layers, and administrative boundaries. Classical ML models remain useful when labels are limited, and predictor variables are tabular or raster-derived. Deep learning can improve segmentation of complex urban textures, but it requires careful labeling and external validation. In coastal regions, urban growth may be spatially adjacent to wetlands, beaches, ports, or industrial facilities, so class definitions should reflect both land-cover type and management relevance.
A recurring risk is that models treat land-cover categories as neutral technical classes. For coastal resilience, the significance of a land-cover transition depends on its location, social context, exposure, and regulatory setting. The conversion of a vacant parcel to impervious surface may have different implications depending on whether it occurs next to a drainage channel, on a barrier island, near a low-income neighborhood, or within a wetland buffer. AI outputs, therefore, require GIS context before they can support adaptation decisions. This is why land-cover change analysis should be integrated with vulnerability layers, infrastructure data, and stakeholder review rather than reported only as area statistics.
3.8. GIS Decision Support and Coastal Governance
GIS is the bridge between AI outputs and coastal decision-making. AI maps are most useful when integrated with administrative boundaries, infrastructure, evacuation routes, conservation areas, land tenure, exposure data, population vulnerability, and planning regulations. Huang et al. emphasize the managerial perspective in deploying spatial data for coastal community resilience [
9]. Diehr et al. review AI and ML-powered GIS for proactive disaster resilience in a changing climate [
10]. These perspectives highlight that the value of AI depends on how outputs are embedded in institutions, not only how accurately they classify pixels.
A practical coastal dashboard might integrate shoreline-change alerts, flood susceptibility layers, post-storm damage maps, wetland health indicators, and restoration-priority rankings. However, dashboards must be maintained, updated, validated, and governed. Without institutional ownership, models risk becoming one-off academic products. Without uncertainty communication, decision-makers may over-trust maps. Without stakeholder participation, models may prioritize technically measurable outcomes over community-defined resilience priorities.
Equity is therefore a central concern. Open satellite data reduces barriers, but vulnerable regions may still lack high-performance computing, training data, field validation capacity, stable internet access, or technical staff.
Figure 3 summarizes a decision-support workflow that links Earth observation, context data, ground truth, preprocessing, AI modeling, validation, explainability, implementation, and equity. This workflow shows why AI-enabled coastal resilience should be designed as capacity-building infrastructure, not merely as a model-building exercise.
3.9. Evaluation Metrics and Common Reporting Pitfalls
Evaluation metrics determine how readers interpret model quality. In coastal remote sensing, a single metric rarely adequately captures performance because model outputs vary across tasks. Shoreline extraction requires geometric accuracy at a narrow boundary. Flood susceptibility mapping requires distinguishing among hazard classes and calibrating against event observations. Mangrove and wetland monitoring requires class-specific accuracy because minority classes can be ecologically important even when they occupy small areas. GIS decision-support systems require usability, update reliability, and stakeholder interpretability in addition to statistical accuracy.
A common reporting pitfall is using random pixel-level train-test splits for spatial data. Random splits can place neighboring pixels from the same scene in both the training and testing sets, inflating performance estimates because the validation data are not independent. Spatial holdout, temporal holdout, event holdout, or cross-region validation provide stronger evidence. This matters in coastal environments because neighboring pixels often share tide, illumination, geomorphology, and sensor conditions. A model that performs well on randomly split data may fail when applied to a different image date or coastline type.
Another pitfall is overreliance on overall accuracy. Overall accuracy can be high when a dominant class, such as open water or inland land cover, overwhelms a smaller but management-relevant class. For shoreline extraction, intersection-over-union may be useful for segmentation masks, but boundary-distance error may better reflect coastal management needs. For flood products, AUC can rank susceptibility but does not tell managers which threshold should trigger action. For ecosystem products, kappa or F1 scores should be accompanied by class-specific precision, recall, and independent ecological validation.
Table 5 links common coastal AI outputs to stronger evaluation practices.
A municipality deciding where to prioritize erosion monitoring requires a different error statement from a researcher comparing segmentation architectures. An emergency manager needs information on lead time, threshold reliability, and uncertainty. A conservation agency needs habitat-specific accuracy and ecological interpretability. When researchers align validation design with the intended decision context, AI outputs become more credible, transparent, and less likely to be overclaimed.
The same principle applies to reproducibility. Researchers should clearly state whether validation labels were interpreted by experts, derived from spectral indices, copied from existing maps, or generated from field observations. They should also report whether the model was tested beyond the training geography. These details help editors and reviewers distinguish robust coastal AI systems from models that perform well only under narrow local conditions.
3.10. Data Governance, FAIR Workflows, and Documentation
Data governance is an implementation requirement, not merely an administrative concern. Coastal AI workflows combine satellite images, derived indicators, field observations, elevation data, infrastructure layers, hazard records, and sometimes social vulnerability data. Each input may have different licensing terms, spatial accuracy, update frequency, and sensitivity. If these differences are not documented, downstream users may misunderstand the reliability or permissible use of the resulting map. For example, an open Sentinel-derived classification can usually be shared widely, but a layer showing critical infrastructure or household-level vulnerability may require access restrictions.
FAIR principles are especially relevant to coastal AI because many studies rely on reproducible processing pipelines. Data should be findable through stable identifiers or clear source descriptions; accessible through documented repositories or official portals; interoperable through common geospatial formats, coordinate systems, and metadata; and reusable through clear licensing and processing documentation. These principles do not require every dataset to be fully public. They require researchers to explain what can be shared, what cannot be shared, and why.
Documentation should also distinguish raw data, preprocessed data, labels, model outputs, and decision products. A shoreline label created by an expert, a water mask produced by thresholding, and a final erosion-risk map are different evidence objects. Combining them without clear provenance makes it difficult to audit the workflow. Coastal AI manuscripts should therefore describe the lineage from input observation to final map. This is particularly important when cloud platforms, automated preprocessing, or AI-assisted labeling are used because reproducibility can depend on software versions, platform defaults, and hidden processing choices.
Table 6.
Data-governance elements that strengthen coastal AI workflows.
Table 6.
Data-governance elements that strengthen coastal AI workflows.
| Governance Element |
Publication-Ready Reporting Expectation |
| Data lineage |
Identify raw data sources, preprocessing steps, label sources, model outputs, and final decision layers. |
| Licensing and access |
State whether data and outputs are open, restricted, proprietary, sensitive, or available upon request. |
| Spatial reference and scale |
Report coordinate system, spatial resolution, resampling choices, and known positional uncertainty. |
| Version control |
Document software platforms, model versions, processing dates, and parameter settings that affect reproducibility. |
| Sensitive information |
Explain how infrastructure, community, or ecological sensitivity was handled when sharing maps or data. |
| Long-term maintenance |
State whether the workflow is a one-time analysis, repeatable research pipeline, or operational system with an update schedule. |
A well-governed coastal AI workflow should be understandable to both technical reviewers and decision-makers. Technical reviewers need sufficient detail to evaluate reproducibility and methodological validity. Decision-makers need enough information to judge whether the map is appropriate for planning, emergency management, restoration prioritization, or public communication. Clear documentation reduces the risk of an AI product being used outside its intended range.
Data governance also supports equity. Communities affected by coastal risk should not only appear as variables in vulnerability layers; they should have opportunities to understand, question, and shape the outputs that may influence planning decisions. When community-level data are used, researchers should discuss safeguards, consent where relevant, and the limits of spatial precision. Responsible documentation can make AI more transparent without exposing sensitive locations or reinforcing unequal data power.