Definition and important uses of CSB

 The International Hydrographic Organization (IHO) defines Crowdsourced Bathymetry (CSB) as the collection and sharing of depth measurements from vessels using standard navigation instruments during their normal operations.

This data provides a valuable, cost-effective method for supplementing traditional, high-precision hydrographic surveys, filling in gaps in the existing maps of the world's oceans and waterways, and fostering a global community of ocean data contributors, while utilizing vessels which are often non-scientific in nature. These can be anything from commercial fishing vessels, to dive boats, to leisure yachts. CSB programs rely on vessels equipped with common marine electronics, such as a depth transducer (echo sounder), a GPS unit, and ideally a motion reference unit (inertial navigation system), often linked through NMEA 2000 or NMEA 0183 networks. Together, these devices provide depth measurements tied to time and position, creating seafloor profiles as vessels move through the water and resulting in a map of the seafloor. As we move into an era of increasingly capable technology becoming more accessible and widespread among vessels, the door to utilizing the masses has opened.

Some of the major strengths of CSB lie in its relative (and increasing) affordability as depth sounders become more capable and simultaneously more connected. This creates the potential for countries or organizations to collect seafloor data on a much larger scale than was previously possible. Additionally, it should be noted that CSB relies on vessels that are often smaller and have a shallower draft than hydrographic research vessels. As a result, CSB can target shallow and narrow water bodies that have long been inaccessible with traditional tools. While CSB isn’t a cure-all solution, its specific strengths allow it to be useful in scenarios such as localized community waterway mapping, or first-time mapping of areas where more advanced tools are financially or physically inaccessible.

While CSB data has historically been overlooked by the hydrographic community at large, the use of a “crowd” helps to bring increased legitimacy to this hydrographic tool. While multibeam data is traditionally utilized within hydrography, a high enough density of single beam data tracks over an area of seafloor could eventually allow data managers to identify and remove outliers, increasing the statistical soundness of the data. This level of sounding density could easily be generated by just a few vessels routinely navigating through the same waterways. As the volume of data within a defined area increases, so too does the accuracy and utility of Crowd Sourced Bathymetry. This approach also allows for high-frequency, low-cost sampling of navigationally significant coastal waterways when compared to traditional hydrographic surveying, as privately owned vessels can collect data on a highly regular basis, and all data are collected in locations where mariners are actively navigating.