To easily confirm a specified facility and a remote facility by selecting and executing any processing among opaque display processing, translucent display processing and wire frame display processing to facility data consisting of polygons included in map data.

When viewpoint position and direction where a map is seen are inputted by a keyboard 3 or a mouse 4 or when they are decided according to an application program, the image processing software 2b of a small computer 2 performs three-dimensional computer graphics processing of map data, such as turning, magnification and reduction and parallel displacement to prepare a landscape map. Here, any processing is selected among opaque display processing, translucent display processing and wire frame display processing and executed to facility data consisting of polygons included in map data. Which processing to be used is stored in the map data in each facility or inputted by using a keyboard 3 and a mouse 4.