GIS has been utilized in sailing and other small craft to help navigate not just the location of other vessels but also land features and obstacles that may arise or even cause danger to boats. Safety, therefore, is often of critical importance, particularly as objects that can cause hazards are constantly changing (e.g., positioning of other boats). In early forms of GIS used for small ships, adaptive GIS processes were critical aspects requiring not only the use of GPS data but other signals as well, including transmitters used for traditional signaling. The signal and geographical contexts are the two critical datasets needed in this approach. Combining contexts and different possibilities between the presence and absence of data within these contexts allow a simple adaptive process for navigation (e.g., another ship emitting a signal that provides a location context). If data are found within the context, then the application can update and provide a view, while data outside the contexts (i.e., no signal) are left without updates or could be interpolated based on known last transmission.
With greater preponderance of mobile phones, commercial applications have been developed to work similarly to GPS devices for cars. GeoRacing is one application that uses GPS signals to track the path of boats using such signals.
However, there is also a need for more developed GIS applications, include integrating more information on hidden as well as surface objects, in particular bathymetry data. GIS tailored for ships has been used to provide nighttime and foggy perspectives, helping to visualize a setting when visibility is affected by conditions. Integration of sonar has been an important development, where TIN models can be utilized to provide real time information on water depth. Another problem area is geodesic calculations needed in real time. An algorithm that replaces integrals for distance and longitude has been one way that addresses this problem. The approach also uses a finite difference method to correct for locations on extreme ends of poles. This method improves calculations over longer distances in particular, where the only limitation to accuracy is the accuracy of the signal and computing precision. With these developments, GIS has been able to substantial benefit safety conditions for small vessels.
 For more information on methods to process signal and geographic contexts, see: Petit, Mathieu, Cyril Ray, and Christophe Claramunt. 2006. “A Contextual Approach for the Development of GIS: Application to Maritime Navigation.” In Web and Wireless Geographical Information Systems, edited by James D. Carswell and Taro Tezuka, 4295:158–69. Berlin, Heidelberg: Springer Berlin Heidelberg.
 For more on GeoRacing, see: http://www.georacing.com/.
 For more information on developing technologies that utilize multiple datasets for navigation, see: Shiotani, Shigeaki, Xinzhu Liu, and Kenj Sasa. 2015. “Basic System of Sea Navigation for a Maneuvering Support System.” In , 1–4. IEEE. Navigation World Conference 2015. doi:10.1109/IAIN.2015.7352249.
 For more on using sonar, see: Fuska, Jakub, PhD; Barek, Viliam; Halaj, Peter; Pokryvkova, Jozefina. 2013. “Evaluation of the Non-contact Measuring of Water Reservoir Bottom Topography.” International Multidisciplinary Scientific GeoConference : SGEM : Surveying Geology & mining Ecology Management. Pg.149-156. Sofia: Surveying Geology & Mining Ecology Management (SGEM).
 For more on Tseng’s method, see: Tseng, Wei-Kuo. 2014. “An Algorithm for the Inverse Solution of Geodesic Sailing without Auxiliary Sphere.” Journal of Navigation 67 (05): 825–44.