Through a combination of gesture input with audio output, the KnowWare™ system offers blind users a new way to access spatial information. An invisible virtual map is defined on the desktop. When the user “touches” a feature on the map with the tip of an index finger, the computer identifies that feature via generated speech or synthesized sound codes. “Touching” (merely placing the finger on a virtual feature that cannot be seen or felt) is detected by means of an overhead video camera that looks down at the user’s hands as they rest upon the desktop. Because KnowWare™ is an electronic medium, it can instantly zoom in on a particular country to display it in more detail. The twenty blind subjects who have tested KnowWare™ were able to use it for most tasks as well as they do traditional raised-line maps.