TruDepth Seamless Layer of UK Bathymetry TruDepth survey bathymetry products represent a collection of Digital Terrain Model (DTM) tiles. The models are based on the best available survey data from authorative sources which are quality controlled and contain detailed information on water depth. After re-engineering, the products designed for a wide range of activities and applications.
The data comes from the best available surveys (for example best sounding density and most up to date surveys) that are held in Seazone's bathymetry database. The SeaZone database includes around 20,000 survey blocks, 500 of which have been scanned, geo-referenced and digitised from UKHO archive fairsheets.
The Grids are supplied to customers as SeaZone TruDepth Grids, available in half degree (~50km) tiles, with a 1 arc-second (~20m) resolution, in ASCII Grid and Esri Binary Grid formats. SeaZone has generated some 200 TruDepth Grids around UK coastal waters and has a development program for complete UK coverage by mid-2011.
One of the most technically challenging elements of producing the TruDepth Grids is the de-confliction process, where areas of overlapping surveys (potentially hundreds) are assessed against set criteria and extents boundaries and soundings are modified and clipped to provide one seamless layer of best available bathymetry. This survey de-confliction is undertaken using new methodology and specially designed GIS tools developed at SeaZone.
SeaZone TruDepth Grids has already been used by a number of key organisations including government, universities, research institutions and consultants. It has been used for marine spatial planning, site selection activities, habitat map creation, volumetric calculations, nutrient loading models, capacity planning and general bathymetry background mapping. The data can be used in most GIS software and as input into modelling programs.
The DTM has been generated from a unique database of some 20,000 multi-beam, lidar and single beam survey blocks covering UK Waters. This data has been authoritatively sourced through the UK Hydrographic Office and captured under the Civil Hydrography Programme or by various ports, harbours and other third parties. Where gaps exist around the UK, analogue survey sheets have been scanned, geo-referenced and digitised by SeaZone. In total, SeaZone has digitised approximately 500 paper fairsheets using a specifically developed quality checking tool to identify any anomalies in the data that need to be reviewed.