An extension to ESRI's, ArcGIS was created to allow spatial data to be represented using sound. A number of previous studies have used sound in combination with visual stimuli, but only a limited selection have looked at this with explicit reference to spatial data and none have created an extension for industry standard GIS software. The extension can sonify any raster data layer and represent this using piano notes. The user can choose from a number of different scales of piano notes and decide how the program plays the sound; this flexibility allows the extension to effectively represent a number of different types of data. The extension was evaluated in one-to-one semi-structured interviews with geographical information professionals, who explored aspects of a number of different data sets. Further research is needed to discover the best use of sound in a spatial data context, both in terms of which sounds to use and what data are most effectively represented using those sounds.