High-resolution coastal topobathymetries dataset

The High-resolution coastal topobathymetries product provides periodic beach topography and shallow water bathymetry measurements. The datasets include sand level measurements (elevation/altitude) covering the entire beach system, typically ranging from approximately +2 m to -15 m depth depending on the site. The output files are delivered in two different formats: very-high resolution multipoint datasets with a best point spacing of ~1 m, and gridded datasets with a spatial resolution of 10 m. The data product also delivers comprehensive quality control flags following established standards, ensuring the reliability of the topobathymetric measurements.

Technical details

The datasets are provided separately for each location in NetCDF format. Each file contains a time series of topobathymetric surveys, gridded on a 10 m grid along the time dimension, following the naming convention site_yyyy0_yyyy1_bathy.nc (e.g., clm_2011_2024_bathy.nc). The files include altitude/elevation parameters, their corresponding quality control flags, and additional metadata. Additionally, multipoint XYZ files at ~1×1 m resolution are generated per site and date, following the convention site_yyyymmdd_bathy.zip for bathymetric surveys and site_yyyymmdd_prof.zip for cross-shore profiles (e.g., clm_20220607_bathy.zip). All individual multipoint files for a given site are bundled together in a single compressed archive named site_yyyy0_yyyy1_bathy.zip (e.g., clm_2011_2024_bathy.zip). A combined multipoint file containing all survey dates merged into a single Shapefile is also provided per site, named site_yyyy0_yyyy1_bathy_merged.zip (e.g., clm_2011_2024_bathy_merged.zip). Each ZIP file contains an ESRI Shapefile in WGS84 coordinates and a JSON file with CF-compliant metadata.

Parameters

This product includes measurements of altitude (geometric height above the geoid) across the dry beach and shallow water domains. The parameters included in the dataset are listed below.

Data sources

Platforms: Valiant DR 620; human

Instruments: BioSonics DT/DE Series Digital Echosounder; R2Sonic 2020 multibeam echosounder; Septentrio Altus RTK-GNSS; Leica GS10 RTK-GNSS; GEOMAX Zenith60 RTK-GNSS

Data quality

The accuracy of the topobathymetric measurements depends on the instrument, surveying method, and environmental conditions. The approximate horizontal and vertical positional accuracy for the altitude parameter is reported as 0.05 m.

Topographic and bathymetric surveys are processed to correct, filter, and flag raw full-density data. The post-processing stage involves data point density reduction (thinning) and interpolation. A rigorous quality control (QC) procedure has been applied to the data. For topographic data (RTK-GNSS), an initial manual cleaning step removes spurious points. For bathymetric data (echosounders), the workflow involves both manual and automatic procedures to mitigate acoustic noise and non-physical outliers. 

Data points that pass these checks are assigned appropriate quality flags. For gridded products, cleaned measurements are resampled by averaging points within 10 m cells, and linear interpolation is used for gap filling. Interpolated cells are assigned a quality flag of 8.

Spatial and Temporal coverage

*There are fewer NetCDF files than multipoint files because profile-only dates (non-bathymetry) were not resampled to a 10×10 grid for NetCDF generation and are instead provided as 1×1 multipoint data.

Contact information

For further technical inquiries or additional information about the dataset, please contact mobims@socib.es