Motor vehicle guidance aid using appearance and disappearance of elements on a displayed map

摘要

The scale of a displayed map is altered between a starting value (S) and a final value (F). Two types of data are distinguished, 'surface' data and 'base' data. A composed image is formed by placing the surface data on the base data. Each pixel in the composed image is evaluated by weighted combination of surface image pixels and base image pixels, with the weighting of the surface image pixel a function of the current value (C) of the map scale.