This paper introduces a new intelligent method to generate vector maps from printed maps to provide a basis for GPS navigation. This new approach has been applied in our GIS-DMG (Digital Map Generation) software, which has four key steps: Map Layers Extraction, Road Network Digitalization, Map Geo-locating and Map Automatic Geo-adjusting, different from typical procedures. These four steps play essential key roles for developing city vector map of GIS. The new intelligent method is effective and less time-cost. The produced city or highway network maps have been well used for GPS applications, e.g., vehicle navigator or intelligent transport system (ITS).