Abstract An efficient, automated system for the collection of spatially variant environmental data has been designed and tested in a limnologic setting. The technique links differentially corrected global positioning system (GPS) data directly with that of a digital environmental sensor. The entire system is fully compatible with geographic information system (GIS) applications and can be utilized for a plethora of applications requiring the simultaneous recording of precise (2–5 m) global position and environmental response variables. A limnologic application of the combination of GPS with an external sensor illustrated the efficacy of this technique. Linking an advanced fathometer directly to GPS through a common data logger facilitated the precise mapping of the physical and biological attributes of a lake in central Oregon. The output from this application was compared to results from a traditional aquatic mapping method, requiring fixed velocity navigation along a set transect. The GPS-fathometry technique greatly out performed the latter method.