Abstract: A display device includes: a first generator to generate first display information for displaying, in a first area, a first map and a first route including a first position in the first area; a second generator to calculate an intersection of an entire route with a boundary of the first area, calculate a tangential area in which a second route connecting a second position and the intersection is inscribed, determine a scale at which the tangential area is included within a second area when the first route and the second route are displayed in such a manner as to be connected to each other at the intersection, and generate second display information for displaying, in the second area, a second map with the scale and the second route; and a controller to control displaying the first display information and the second display information in a combined manner on a display.

Abstract: An image-rendering device: divides a large region whose minimum configuration unit is an element into small regions each configured with the elements; calculates low resolution distance data showing a distance from a base line serving as a reference for color change in gradation for each of the small regions; associates low resolution distance data showing each distance from the base line for each of the small regions with high resolution distance data showing each distance from the base line to each of the elements, and stores them in high resolution data storage; obtains, from the high resolution data storage, the high resolution distance data associated with the calculated low resolution distance data; and renders gradation on the basis of the high resolution distance data. Therefore, it is possible to reduce the number of times for calculating a minimum distance between the base line and each pixel.