Whilst the remit of national hydrographic offices is generally to meet the needs of defence and commercial shipping, there is increasing pressure to meet the needs of other seagoers (which vastly outnumber the commercial shipping sector), and the increasing needs of the Blue Economy more more data. Against this, funding for surveys is generally being cut. This is causing many hydrographic offices to consider how they can best use more cost effective methods than deploying survey vessels.
Crowd sourced bathymetry is being studied by the IHO, with their establishment of a crowd sourced bathymetry working group. TeamSurv are active participants in the group, providing input from their experience to the cookbook being written, and also providing trial data sets. We will also be one of the nodes uploading data to the IHO's repository, once this is in place.
But successful use of crowd sourced bathymetry is more than just having a collection of vessel tracks. The error characteristics are notably different from professional single beam surveys. TeamSurv have built up a high degree of expertise in understanding and processing crowd sourced data, and have built up a suite of statistical algorithms to process the data effectively - our equivalent of the CUBE algorithm used for multi-beam surveys.
The accuracy of crowd sourced bathymetry increases as the number of tracks, and the number of vessels, in an area increase. In validating our data against contemporaneous multibeam surveys, we have found that where we have reasonable data coverage we can readily obtain IHO S-44 Order 2 levels of accuracy, increasing to Order 1b as the data density increases.
Hydrographic offices have a duty to fully investigate any data submitted to them, so many are concerned that a flood of crowd sourced data will place a heavy load on their resources, without necessarily providing much new data. TeamSurv can help with this by comparing crowd sourced bathymetry against a base bathymetry layer, and just advising the hydrographic office when a significant change is detected.
Lidar and satellite derived bathymetry are both being increasingly accepted by hydrographic offices, but to achieve maximum accuracy they generally benefit from having some ground truth data from the area they are covering. Having to deploy a survey vessel can negate many of the cost benefits of these methods, but crowd sourced bathymetry can provide this, as we are demonstrating in the Base Platform project.
In addition to national hydrographic offices, there are numerous publishers of bathymetric data for commercially produced nautical charts and for non-navigational use, often in GIS compatible file formats or as digital terrain models (DTMs).
For incorporating crowd sourced data into other data sets, our recommendation is that we provide the data in our adaptive grid, which is a sparse, variable resolution grid providing mean depth data plus a number of quality metrics. This may be based on just data from TeamSurv's fleet, or it may incorporate tracks from other sources, such as the IHO DCDB. Alternatively we can provide surfaced data sets as a DTM in a number of formats, which offers easier processing though the information content is not as rich.
Please contact us to discuss how we can best help you.