MAP DISPLAY DEVICE, MAP DISPLAY METHOD, COMPUTER PROGRAM AND RECORDING MEDIUM

摘要

PROBLEM TO BE SOLVED: To suppress the sudden change in the width of a feature at the time of changing the scale over a switching scale.SOLUTION: A map display device comprises: large scale map data which performs polygon display of the shape of a feature; small scale map data which performs polyline display of the shape of the feature; and map display means which displays a large scale map in an enlarging/contracting manner with a polygon when the map display scale is within a large scale range, and displays a small scale map in an enlarging/contracting manner with a polyline when the map display scale is within a small scale range to continuously perform map display from the large scale range to the small scale range. The map display means comprises: a display continuation part which continues display with the polygon at least to a reference scale from the large scale range to the small scale range when the size of the polygon in a prescribed switching scale is greater than the size of the polyline by a prescribed value; and an alternative display part which performs display by using an alternative polyline complementing the difference in the size between the polygon and the polyline instead of the polyline when the size of the polygon in the prescribed switching scale is smaller than the size of the polyline by the prescribed value.SELECTED DRAWING: Figure 1