Abstract: PEANO normalized linear key is based on, 2D spa.ee filling curve character. This paper introduces its concepts, and its application in computer. map ping. Due to its ability of reordering the 2D random data ppints in pne dimension sequence, it is an efficient tool for 2D space search. It is proposed to be used in geoscientific mapping, GIS and any space information system. Its principle is also suitable for nD space search.