Approach for optical satellite imagery Source: DigitalGlobe WorldView-2, acquisition date: Indicative / empirical methods: Relate brightness to water depth Photogrammetric / stereo approach: Find matching points on seafloor Multispectral, physics based approach: Resolve light-transfer and retrieve optical properties
Approach for optical satellite imagery (Semi-) EmpiricalPhysical Setup & investmentEasySophisticated Location independent (In situ data not mandatory) NoYes Uncertainties traceable (independent on in-situ data) NoYes Production capabilityDependent on in situ data availability Large, highly automatable Methods Relating brightness or log-ratios to depth (e.g. Lyzenga et al., Stumpf, etc) Resolving the light transfer (e.g. CSIRO SAMBUCA, EOMAP MIP) Focus on the multi-spectral approach:
Un-corrected imagery: view at sensor Heron Island, WorldView-2 Radiances (RGB: ch4, 3, 2) Source: DigitalGlobe WorldView-2, acquisition date:
2m spatial resolution SDB Acquisition date: 3 rd Mar m spatial resolution SDB Acquisition date: 24 th Jan 2014 Nautical chart Scale: 1:35 000, Ed Mulitple resolutions between 0.5m and 30m grid spacing Example: Sir Bani Yas island, Abu Dhabi Sir Bani Yas Island Sir Bani Yas Island
Off-The-Shelf Bathymetry – BASEMAPS Improved transnational base maps for planning Off-the shelf catalogue Resolutions: 30m,.. 70 cm > 1 Mill sqkm mapped in 2013/2014
What happens next? Objective: Increase awareness and acceptance of satellite derived bathymetry Rapid availability also in remote areas, independent, Cost effective synthesis with hydrographic surveys Supporting initial planning or reconnaissance in hydrographic applications SDB standards development Operational uncertainty values: prove and define Definition of SDB product and qualification categories: Quantitative depth, indicative depth, minimum depth, map representation Seafloor, Obstructions, Environment Supporting Trans-national Base-maps and electronic data sets Large scale production of relevant SDB product categories Easy access: Integration into online portals and electronic charts Regular updates, change monitoring, multi-source integration
We acknowledge contributions from: Don Ventura, Fugro Arnold Dekker, CSIRO Thank you! Questions?