In this paper we describe our investigation of using interactive sonification (non-speech sound) to present the geographical distribution pattern of statistical data to vision impaired users. We first discuss the design space in the dimensions of interaction actions, data representation forms, input devices, navigation structures, and sound feedback encoding. Two interfaces have been designed according to the design space, one using a keyboard and another using a smooth surface touch tablet. A study with three blind users shows that they are able to perceive patterns of 5-category values on both familiar and unknown maps, and learn new map geography, in both interfaces.