Abstract: A map database stores map data in multiple levels having different levels of details. In displaying a three-dimensional map, the map data having a higher level of details is used for a close view area near the viewpoint to a predetermined distance, and the map data having a lower level of details is used for a distant view area farther from the predetermined distance. The distant view area is first drawn by a perspective projection, and then, after clearing a depth buffer that stores depth information, the close view area is drawn, such that an undesirable hidden line removal process based on the depth information is not performed between the projected image in the distant view area and that in the close view area, thereby avoiding an unnatural phenomenon in which part of the close view image is hidden by the distant view image.

Abstract: A projection (projected image) is drawn by perspective projection of a three-dimensional model with a background image having improved reality. When a sightline of the perspective projection looks down from above, the projected image is drawn into an object drawing area which is a lower part of an image picture. A background layer representing the stratosphere is separately generated by two-dimensionally drawing a background image, in which the stratosphere (hatched area) is opaque, while the remaining area is transparent. The boundary between the opaque portion and the transparent portion forms a curved line that is convex upward to express a curved horizon. The background layer is superimposed in front of the projected image, not behind the projected image, thereby covering an upper edge portion of the projected image including a straight-lined upper edge, so as to provide a curved boundary realizing a curved pseudo horizon in the image picture.

Abstract: A three-dimensional (3D) map display system displays a 3D map on which a ground surface and a feature are represented three-dimensionally. The 3D map display system includes (a) a map database for storing map data representing a 3D shape of the ground surface and the feature, (b) a first drawing unit for drawing the ground surface and the feature by executing depth determination by referring to the map database, and (c) a second drawing unit for drawing a target feature, which is a feature in which at least a part thereof is hidden by a ground surface or other features in the drawing by the first drawing unit, by overwriting the target feature on a drawing result by the first drawing unit by using the map data without executing depth determination with respect to the drawing result by the first drawing unit.

Abstract: A map database stores three-dimensional polygons of features, as well as water system polygons such as sea and lake and ground surface polygons. The map database stores map data in multiple levels having different levels of details, such as levels LVa to LVc. A procedure of displaying a three-dimensional map offsets the water systems relative to the ground surfaces, draws a map of a distant view area distant away from the viewpoint using map data at a low level of details, subsequently clears a depth buffer and newly draws a map of a close view area close to the viewpoint using map data at a high level of details. The offset is set to increase in the distant view area and decrease in the close view area. Increasing the offset in the distant view area avoids the occurrence of Z-fighting in the distant area from the viewpoint.

Abstract: A three-dimensional map is displayed in a bird's eye view with a stereoscopic effect of feature polygons by providing shading in an appropriate direction according to the gaze direction in a simulative manner. Shading wall polygons are set in addition to feature polygons in three-dimensional map data. The shading wall polygon is a virtual plate-like polygon provided vertically, for example, along a boundary of a feature polygon. When provided around the water system, the shading wall polygon is specified to be opaque on one surface viewed from the water system side and to be transparent on the opposite surface. The shading wall polygons are drawn along with the feature polygons in the process of displaying a map. The shading wall polygon is drawn in black, gray or the like only at a location where the surface specified to be opaque faces a gaze direction.

Abstract: A stereoscopic image output system includes a stereoscopic vision output unit, an image database storage unit, and an output control unit. The stereoscopic vision is realized by outputting, from the stereoscopic vision output unit, a left-eye image and a right-eye image with parallax such that the left and right-eye images are visually recognized by the left and right eyes, respectively. Left-eye parallel projection data and right-eye parallel projection data are generated by parallel projection of a three-dimensional model using respective projection angles set for the left eye and right eye so as to produce the parallax therebetween, and stored in the database storage unit as two-dimensional drawing data. The output control unit controls an output range of the left and right-eye images. If the output range for the stereoscopic image changes, moving directions of the left-eye image and the right-eye image are individually determined by the output control unit.

Abstract: A stereoscopic map display system includes (a) a stereoscopic vision display unit for providing a stereoscopic vision by displaying a right-eye image and a left-eye image with parallax so as to be visually recognizable by the right eye and the left eye, respectively, (b) a map database storage unit for storing map data, and (c) a display control unit for providing the right-eye image and the left-eye image at least part of which has the parallax, to the stereoscopic vision display unit based on the map data. The map data stores feature data indicating a shape of a feature and a display-depth adjusted object indicating an object other than the feature and displayed by a display depth under a predetermined rule. The display control unit displays the display-depth adjusted object with the multi-staged display depths under a predetermined rule for an attribute or a display position thereof.

Abstract: In displaying a 3D map, a feature image is generated by perspective projection of the feature based on a predetermined position of the point of sight and a predetermined direction of the line of sight. A plate polygon on which characters are pasted is arranged in a virtual 3D space in a direction along a road and tilted from the ground surface, and parallel projection is applied to the plate polygon so as to generate a character image. A tilt angle between the plate polygon and the ground surface is set based on a display direction of the road and a display position of the character. Thus, by generating the feature image by perspective projection while generating the character image by parallel projection, negative effects such as crushing of distant characters can be avoided, whereby the characters can be displayed in three-dimensional shape without reducing visibility thereof.

Abstract: Representation of undulation with a light processing load is realized using three-dimensional ground surface data. Ground surface data representing a three-dimensional shape of a ground surface is stored in a map database. A two-dimensional image representing contrast of the ground surface is also generated by projecting the ground surface data by applying lighting thereto, and the two-dimensional image is stored in map data as a ground surface texture. In displaying the map, the ground surface texture is pasted on the ground surface data and perspective projection is performed. By such a configuration, even without applying lighting, a map can be provided which can give undulation of a ground surface with a light processing load.

Abstract: A 3D map representing a feature that cannot be visually recognized such as an underground structure is displayed without a sense of discomfort. Among features stored in the map database, underground structures such as tunnels are classified into transmissive objects, and other features into non-transmissive objects. Then, the transmissive objects and the non-transmissive objects are projected individually so as to generate a transmissive object projection view and a non-transmissive object projection view. The transmissive object projection view thus obtained is superposed on the non-transmissive object projection view with adjusted transmittance. Making the transmissive objects to be transmissive and superposing them enables to realize a map that appears to the user as if a ground surface or features which blocked the transmissive objects are made to be transmissive whereby the transmissive objects become visible.

Abstract: A thee-dimensional (3D) map display system displays a 3D map on which a ground surface and a feature are represented three-dimensionally. The 3D map display system includes (a) a map database for storing map data representing a 3D shape of the ground surface and the feature, (b) a first drawing unit for drawing the ground surface and the feature by executing depth determination by referring to the map database, and (c) a second drawing unit for drawing a target feature, which is a feature in which at least a part thereof is hidden by a ground surface or other features in the drawing by the first drawing unit, by overwriting the target feature on a drawing result by the first drawing unit by using the map data without executing depth determination with respect to the drawing result by the first drawing unit.

Abstract: A three-dimensional map display system displays a three-dimensional map representing features thereon three-dimensionally. The system includes a map database, a projection view generation unit, and an attribute representation image superimposing unit. The map database stores drawing data including a three-dimensional model of a feature and appearance attribute information representing an appearance attribute of the feature, by associating the drawing data and the appearance attribute information with each other. The projection view generation unit generates a projection view by projecting the drawing data.

Abstract: A drawing data generation device performs an integration process on map data so as to integrate line data for drawing linear features such as roads, such that a drawing speed of a map image is improved. The line data is grouped by the line type and the line width. The integration process links thin solid lines L1 and L3 by a non-display line LA1, and links thick solid lines L2, L4 and L5 by non-display lines LA2 and LA3, for example, so as to integrate the line data of a plurality of lines into integrated line data for an integral line formed of linked lines in a same group.

Abstract: A projection (projected image) is drawn by perspective projection of a three-dimensional model with a background image having improved reality. When a sightline of the perspective projection looks down from above, the projected image is drawn into an object drawing area which is a lower part of an image picture. A background layer representing the stratosphere is separately generated by two-dimensionally drawing a background image, in which the stratosphere (hatched area) is opaque, while the remaining area is transparent. The boundary between the opaque portion and the transparent portion forms a curved line that is convex upward to express a curved horizon. The background layer is superimposed in front of the projected image, not behind the projected image, thereby covering an upper edge portion of the projected image including a straight-lined upper edge, so as to provide a curved boundary realizing a curved pseudo horizon in the image picture.

Abstract: A three-dimensional map effectively uses a space of the sky or the background to display character strings. A transmitter/receiver obtains map data used to display each feature three-dimensionally and character data representing a character string to be displayed in the three-dimensional map from a map database. A feature image generator generates a feature image in which each feature is drawn three-dimensionally. A character display controller controls display of the character string on the feature image. The character display controller changes over at least one of a display direction and a number of display lines of the character string with respect to each of a plurality of areas in the feature image specified according to a distance from a viewpoint set for generating the feature image, such that a length of the character string in a vertical direction increases with a decrease in distance from the viewpoint.

Abstract: A map database stores map data in multiple levels having different levels of details. In displaying a three-dimensional map, the map data having a higher level of details is used for a close view area near the viewpoint to a predetermined distance, and the map data having a lower level of details is used for a distant view area farther from the predetermined distance. The distant view area is first drawn by a perspective projection, and then, after clearing a depth buffer that stores depth information, the close view area is drawn, such that an undesirable hidden line removal process based on the depth information is not performed between the projected image in the distant view area and that in the close view area, thereby avoiding an unnatural phenomenon in which part of the close view image is hidden by the distant view image.

Abstract: A map database stores three-dimensional polygons of features, as well as water system polygons such as sea and lake and ground surface polygons. The map database stores map data in multiple levels having different levels of details, such as levels LVa to LVc. A procedure of displaying a three-dimensional map offsets the water systems relative to the ground surfaces, draws a map of a distant view area distant away from the viewpoint using map data at a low level of details, subsequently clears a depth buffer and newly draws a map of a close view area close to the viewpoint using map data at a high level of details. The offset is set to increase in the distant view area and decrease in the close view area. Increasing the offset in the distant view area avoids the occurrence of Z-fighting in the distant area from the viewpoint.

Abstract: A three-dimensional map is displayed in a bird's eye view with a stereoscopic effect of feature polygons by providing shading in an appropriate direction according to the gaze direction in a simulative manner. Shading wall polygons are set in addition to feature polygons in three-dimensional map data. The shading wall polygon is a virtual plate-like polygon provided vertically, for example, along a boundary of a feature polygon. When provided around the water system, the shading wall polygon is specified to be opaque on one surface viewed from the water system side and to be transparent on the opposite surface. The shading wall polygons are drawn along with the feature polygons in the process of displaying a map. The shading wall polygon is drawn in black, gray or the like only at a location where the surface specified to be opaque faces a gaze direction.

Abstract: A stereoscopic image output system includes a stereoscopic vision output unit, an image database storage unit, and an output control unit. The stereoscopic vision is realized by outputting, from the stereoscopic vision output unit, a left-eye image and a right-eye image with parallax such that the left and right-eye images are visually recognized by the left and right eyes, respectively. Left-eye parallel projection data and right-eye parallel projection data are generated by parallel projection of a three-dimensional model using respective projection angles set for the left eye and right eye so as to produce the parallax therebetween, and stored in the database storage unit as two-dimensional drawing data. The output control unit controls an output range of the left and right-eye images. If the output range for the stereoscopic image changes, moving directions of the left-eye image and the right-eye image are individually determined by the output control unit.

Abstract: A stereoscopic map display system includes (a) a stereoscopic vision display unit for providing a stereoscopic vision by displaying a right-eye image and a left-eye image with parallax so as to be visually recognizable by the right eye and the left eye, respectively, (b) a map database storage unit for storing map data, and (c) a display control unit for providing the right-eye image and the left-eye image at least part of which has the parallax, to the stereoscopic vision display unit based on the map data. The map data stores feature data indicating a shape of a feature and a display-depth adjusted object indicating an object other than the feature and displayed by a display depth under a predetermined rule. The display control unit displays the display-depth adjusted object with the multi-staged display depths under a predetermined rule for an attribute or a display position thereof.