JP2009059101A - Three-dimensional object processor, three-dimensional object processing method and three-dimensional object processing program - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a three-dimensional object processor, a three-dimensional object processing method and a three-dimensional object processing program, allowing more effective materialization of arbitrary designation of an attitude of the earth by a user and interpretation of the world from experience by interaction from a new viewpoint, recognition of difference between a map and the real world, or the like. <P>SOLUTION: This three-dimensional object processor has: a projection means expressing a sphere or a spheroid by a plurality of polygons, and projecting vertex positions of the polygons in a three-dimensional object having the surface expressed with the earth surface onto a circular cylinder; a development display means developing the circular cylinder and making a plane thereof be displayed while converting the vertex positions of the polygons into orthogonal coordinates on the plane; and a storage means storing a color table prescribing drawing color according to an altitude value in each spot constituting a planar earth map. The development display means makes the drawing color of the spot corresponding to the converted orthogonal coordinates to be displayed by the drawing color corresponding to the altitude value in the spot in reference to the color table when developing the circular cylinder. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a method for creating a global map that enables interaction with a user, and in particular, an apparatus and a method that allow a user to arbitrarily specify the attitude of the earth by performing dynamic map projection in real time. Related to the technical field.

  Conventionally, various methods for creating an earth map by projecting the earth as a sphere or spheroid to a plane, for example, are known, but errors occur when the earth as a sphere or spheroid is projected onto a plane. There are various problems such as. As a method for solving one of such problems, for example, Patent Document 1 discloses a non-obtained method obtained by dividing an earth map as a spheroid into predetermined longitude bands and predetermined latitude bands according to the UTM projection. A map database that stores projection map data defined by coordinate addresses on equilateral squares, and for each of the above sections, coordinate addresses on unequal squares of each section are maintained in the array and number of data in that section. There is disclosed a map creation apparatus comprising means for converting into coordinate addresses on an equilateral quadrangle, a memory for storing map data defined by the coordinate addresses on the equilateral quadrangle after conversion.

  By the way, many of the world maps that are close to us are based on the Mercator projection or similar projections, and have given us a world view with high latitudes distorted. This cartographic map has made it possible to share a common world view, but it has become difficult to interpret the world from a new perspective and to recognize the difference between the map and the real world.

  Until now, maps that have been developed in print media have had to read information given unilaterally and required some knowledge and training. However, in recent years, interactive earth maps using computers have been announced (for example, Google Earth http://earth.google.co.jp/), and it has become possible to interpret information not only through reading but also through interactive experiences. .

Patent Documents 2 to 4 also propose techniques related to the above.
JP 2001-118051 A Japanese Patent Laid-Open No. 11-83502 JP-A-10-91064 JP-A-6-138816

  However, the interaction with the existing interactive earth map is often for manipulating which part of the world map of the print media is to be cut out at what size. With these interactive Earth maps, it became possible to investigate the names of buildings far away and the way to the destination in detail, but when looking down at the earth, it is the same as the world map and globe of print media, Or I could only get an experience close to that.

  In view of such points, the present invention allows the user to arbitrarily specify the attitude of the earth, interpret the world from a new viewpoint from the experience of interaction, recognize the difference between the map and the real world, etc. An object is to provide a three-dimensional object processing device, a three-dimensional object processing method, and a three-dimensional object processing program that can be realized more effectively.

  In order to solve the above-mentioned problem, the invention described in claim 1 is characterized in that a sphere or a spheroid is expressed by a plurality of polygons, and a vertex position of the polygon in a three-dimensional object in which the surface of the earth is represented on a surface is a cylinder. Projection means for projecting, unfolding display means for displaying the plane by expanding the cylinder while converting the vertex position of the polygon into orthogonal coordinates on the plane, and elevation values at each point constituting the planar earth map Storage means for storing a color table that defines a drawing color according to the above, and the unfolding display means displays the drawing color of the point corresponding to the converted orthogonal coordinates when unfolding the cylinder. With reference to the color table, it is displayed in a drawing color corresponding to the altitude value at the point.

  According to a second aspect of the present invention, in the three-dimensional object processing device according to the first aspect, the unfolding display unit corresponds the orthogonal coordinates of a plurality of points inside the polygon on the plane to the vertex positions of the polygon. The drawing color of the point corresponding to the calculated orthogonal coordinate is displayed with the drawing color corresponding to the elevation value at the point with reference to the color table.

  According to a third aspect of the present invention, in the three-dimensional object processing apparatus according to the second aspect, the change control means for changing the reference level of the drawing color according to the altitude value according to an instruction from the user via the input means. The development display means changes the drawing color of the point on the already displayed plane with reference to the color table every time the reference level is changed.

  The invention of the three-dimensional object processing program according to claim 4 causes a computer to function as the three-dimensional object processing apparatus according to any one of claims 1 to 3.

  According to a fifth aspect of the present invention, a step of projecting a vertex position of the polygon in a three-dimensional object in which a sphere or a spheroid is represented by a plurality of polygons and the surface of the earth is represented on a surface to a cylinder; An unfolding and displaying step for displaying the plane by expanding the cylinder while converting the vertex position into Cartesian coordinates on the plane, and a color for defining a drawing color corresponding to the altitude value at each point constituting the planar earth map Storing the table, and in the unfolding display step, when the cylinder is unfolded, the drawing color of the point corresponding to the converted orthogonal coordinate is referred to the point of the color table. It is characterized by being displayed in a drawing color corresponding to the altitude value at.

  According to the present invention, when the cylinder is expanded, the drawing color of the point corresponding to the orthogonal coordinate converted from the vertex position of the polygon is referred to the color table with the drawing color corresponding to the elevation value at the point. Since it is made to display, a quick process is attained and a user can be made to interpret the world from a new viewpoint further.

  DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, the best embodiment of the invention will be described with reference to the accompanying drawings.

A three-dimensional object processing apparatus and method according to the present invention includes a processing unit (comprising a CPU, etc.), a storage unit (comprising a VRAM, a ROM, a hard disk drive, etc.), a display unit (comprising a display, etc.), and an operation unit (mouse). This is realized by installing and starting the earth map creation software (including the three-dimensional object processing program according to the present invention) on a general-purpose personal computer having a keyboard and the like. In this embodiment, the processing unit includes a GPU (Graphics Processing Unit) for real-time calculation processing of a display color determination program.
[1. Basic algorithm]
First, the basic algorithm of the global map creation software according to this embodiment will be described.

  FIG. 1 shows an example of the algorithm configuration of the global map creation software according to this embodiment.

  By this algorithm, the earth object as a three-dimensional object (the surface of the earth is represented on the surface of the object) is displayed in the globe mode and the map mode, and can be switched to each other. Note that the static data of the earth object can be referred to and presented regardless of the presence or absence of the map projection.

  In the globe mode, as an operation of the earth object that affects the map, the user rotates the earth object displayed on the display by moving the mouse (moving the pointer) while dragging the earth object with the mouse. Can do. The rotation of the earth object is applied to the earth object before projecting the map, and a known quota anion is used to perform an intuitive operation in a spherical state and to prevent gimbal lock. The rotation of the earth object is possible in any direction of 360 degrees on the plane. Further, the speed when the pointer is moved while dragging the earth object with the mouse is measured, and the earth object is rotated at the speed.

  In this specification, latitude and longitude are expressed as shown in (1.1) below.

(E│w│n│s) (angle) (1.1)
Here, e represents east longitude, w represents west longitude, n represents north latitude, s: south latitude, and the angle is 0 to 180 for e or w, and 0 to 90 for n or s.

  In the shape model of the earth object, a sphere (which may be a spheroid) is approximately represented by a plurality of polygons (in this embodiment, a triangle formed by three vertices). The vertex position of each polygon is arranged on a sphere having a radius of 1, for example, with the center of the object as the origin, and is associated with latitude and longitude. The vertex position of each polygon is an intersection formed by equally dividing between n90 and s90 and between e180 and w180. The number of divisions is nDivLat and nDivLng, respectively, and the vertex position is obtained by converting the latitude and longitude values of the intersections obtained by the division into an orthogonal coordinate system.

  Conversion to Cartesian coordinates is expressed by the following equation (1.2).

x = cos (rLat) * sin (rLng)
y = sin (rLat)
z = −cos (rLat) * cos (rLng)
(1.2)
Here, rLat and rLng represent latitude and longitude in radians.

  Each vertex holds a normal vector and texture coordinates. Since the earth object is a sphere having a radius of 1, the normal vector has the same value as the vertex position vector. The texture coordinates can be mapped (texture mapping) to an image including a range of e180 to w180 and n90 to s90 at a corresponding position on the sphere. Note that the texture image does not have to be a single image and can be mapped using a plurality of images covering the above range.

  On the other hand, in the map mode, an earth object is projected onto a cylinder, and the cylinder plane is expanded to display the map plane. Also in this case, an image corresponding to the latitude and longitude can be mapped (texture mapping) to a corresponding position on the map plane.

  Note that processing such as texture mapping is performed in units of polygons. That is, the three vertex coordinates of the polygon are read and processed.

  The display switching between the globe mode and the map mode is performed by continuously changing animation. In such an animation, only a corresponding point between the sphere and the map plane is used to realize a smooth trajectory. The sphere in globe mode is a sphere with radius 1 centered on the origin, and the map in map mode is z = 1 (x and y ranges are -π≤x≤π and -2≤y≤2 respectively). The trajectory of the corresponding point in each mode is obtained by interpolation. The interpolation is performed with an angle and a distance. The angle is a spherical linear interpolation according to the following equation (1.3), and the distance realizes a smooth motion using the linear interpolation.

Slerp (t, q ₀ , q ₁ ) = {q ₀ sin [θ (1-t)] + q ₁ sin (θt)} / sinθ (1.3)
Here, q ₀ and q ₁ are the end point quaternions, and θ is an angle formed by q ₀ and q ₁ . T represents the weight of interpolation, and 0 ≦ t ≦ 1.

According to the above equation (1.3), a line segment representing the shortest distance between any two points on the sphere can be obtained. For this line segment, for example, an end point is specified by clicking with the mouse, and the latitude and longitude of the earth object pointed to are acquired. As a specific implementation method, the clicked point is converted from the screen coordinate system to the world coordinate system, the intersecting polygon and the intersection of the polygon are calculated, and the latitude and longitude are obtained. If such a shortest distance is displayed, it also functions as a reference for assisting spatial grasp along with latitude and longitude lines.
[2. Projection cylindrical projection algorithm]
Next, a flat cylindrical projection algorithm of the earth map creation software according to the present embodiment will be described.

  The position after projection is calculated using the vertex coordinates P of the polygon in the earth object as input. Flat projection is used for map projection. This calculation is obtained by (1) calculating the light source position, (2) projecting the vertex position of the polygon onto the cylinder, and (3) expanding the cylinder. The coordinate system in each projection state is as shown in FIG.

Hereinafter, (1) to (3) will be described in detail.
(1) Calculation of light source position FIG. 2 is a diagram showing a state in which the vertex position of a polygon is projected onto a cylinder by the orthographic projection method. The light source position L in the orthographic projection is expressed by the following equation (2.3) and depends on the vertex coordinate P.

L = −A / │A│
A = (P _x , 0, P _z )
(2.3)
Here, the point A is a point obtained by projecting the point P on the xz plane.
(2) Projecting the vertex position of the polygon onto the cylinder The position C after projection onto the cylinder is expressed by the following equation (2.4).

C = L + 2V / R
V = P−L
R = √ (V _x ^ 2 + V _z ^ 2)
(2.4)
Here, the vector V is a vector from the light source L toward the vertex coordinate P. The scalar R is the length when the vector V is projected onto the xz plane.
(3) Expanding the cylinder When the radius of the earth object is 1, for example, and projected onto a cylinder having the same radius, the position in the horizontal direction (x-axis) of the plane after the expansion is calculated from the angle of the cylinder. Further, the position M after the expansion is expressed by the following formula (2.5).

M = (M _x , C _y , 1)
M _x = Sign (C _x ) ・ arccos (D ・ E)
D = (0, −1)
E = (C _x , C _z )
Sign (a) = {1 (a ≧ 0), −1 (a <0)
... (2.5)
The y-coordinate after development on the plane is C _y and the z-coordinate is 1. The x coordinate is calculated according to the angle formed by the vector D and the vector E. Note that when the radius r of the earth object is 1, the size of the map plane after the projecting cylindrical projection is 4 in the vertical direction and 2π in the horizontal direction.

As described above, the vertex positions of the polygons are converted into orthogonal coordinates on the map plane.
[3. Complementary algorithm for cylinder expansion]
Next, a supplementary algorithm at the time of cylindrical expansion of the global map creation software according to the present embodiment will be described.

  FIG. 3 is a conceptual diagram showing how a cylinder onto which the vertex positions of polygons are projected is developed.

  In the following description, a line that develops a cylinder and becomes a cut line of the cylinder is referred to as a seam line. Among the plurality of polygons constituting the earth object, some polygons exist on the seam line and cross the seam line (that is, the outline of the polygon intersects the seam line). In the example of FIG. 3A, a polygon PO1 having three vertices P0, P1, P2 is crossed by a seam line LI. In practice, a plurality of polygons exist on the seam line LI, but the illustration is omitted for convenience of explanation. When the polygon PO1 is developed on the map plane F, the processing unit recognizes it as an elongated triangle in the map plane F as shown in FIG. For this reason, the left and right sides H1 and H2 of the map plane F coinciding with the seam line LI are not linear and are projected and displayed with a jagged outer shape.

  In addition, any two of the plurality of polygons constituting the earth object intersect with the central axis of the cylinder (through the central axis). In the example of FIG. 3A, a polygon PO2 (upper part of the cylinder T) having three vertices P3, P4, and P5 intersects the central axis G (y axis) of the cylinder T. Actually, a polygon that intersects the central axis G of the cylinder T also exists in the lower part of the cylinder T. When the polygon PO2 is developed on the map plane F, the processing unit recognizes it as an elongated triangle as shown in FIG. For this reason, the upper side H3 of the map plane F (in the example shown in the figure, the ideal position of H3 is indicated by a broken line for easy understanding) is not linear, but is projected and displayed with a distorted outline. End up. The same applies to the lower side H4.

  Here, actual display examples are shown in FIGS.

  FIG. 4 shows a display example of the earth object displayed in the globe mode.

  In the example of FIG. 4A, the north pole is located at the uppermost end of the screen, the south pole is located at the lowermost end of the screen, and the axis G passing through the north and south poles corresponds to the central axis G of the cylinder T described above. become. In such a display state, when the user drags the earth object OB with the mouse and moves the mouse diagonally upward to the right, for example, the earth object OB rotates in the direction of the arrow in FIG. It is displayed as shown in (B). In the example of FIG. 4B, the north pole is no longer at the top edge of the screen, and the south pole is no longer at the bottom edge of the screen. In other words, the rotation of the earth object OB makes it possible to locate points other than the North Pole and the South Pole (for example, Japan) at the uppermost end of the screen and the lowermost end of the screen. However, the earth object OB axis G (center axis G of the cylinder T) does not change.

  4B, for example, when the user moves the mouse pointer to the earth object OB and clicks the mouse button (instruction to shift to the map mode), the earth object OB is projected by the algorithm described above. Then, the map mode is displayed and a map plane F as shown in FIG. 5 is displayed. As described with reference to FIG. 3B, the map plane F shown in FIG. 5 has its right and left sides H1 and H2 displayed with a jagged outer shape, and its upper and lower sides H3 and H4 have a distorted outer shape. None of them are displayed in a straight line, and the appearance is very poor. Even in such a display state, it is possible to change the display state by moving the point located on the map plane F by a mouse operation (for example, dragging and moving) by the user. In such a transition, the jagged outer shape of the left and right sides H1, H2 changes, and the distorted outer shape of the upper and lower sides H3, H4 changes.

  If the earth object OB cannot be rotated as shown in FIG. 4A, that is, if the positions of the north pole and the south pole are fixed, the above-described jagged outer shape when expanded on the map plane is complemented. However, in the configuration of the present embodiment, since the earth object OB or the map plane F can be rotated or the like, the complementation is difficult.

  The inventor has devised a complementation algorithm for complementing the jagged outer shape on the left and right sides H1 and H2, and a complementation algorithm for complementing the distorted outer shape of the upper and lower sides H3 and H4. Hereinafter, the supplementary algorithm will be described in detail with reference to FIG. FIG. 6 is a conceptual diagram showing a state of complementation when a cylinder onto which a vertex position of a polygon is projected is developed.

  First, a complementary algorithm for the left and right sides H1 and H2 will be described.

  In such a complementary algorithm, as described above, after the vertex positions of the polygons are projected onto the cylinder, the extraction unit of the processing unit has the outline (also referred to as a side or a line segment) among the plurality of polygons constituting the earth object. However, a polygon intersecting the seam line LI (for example, a polygon PO1 having vertices P0, P1, P2 shown in FIG. 6A) is extracted. In practice, a plurality of polygons are extracted by such processing. Further, the three vertex coordinates of the extracted polygon are temporarily stored at a predetermined address in the RAM. The polygon can be extracted even before the vertex position of the polygon is projected onto the cylinder. This is because the position of the seam line LI can be recognized even in the state of the axis G of the sphere before being projected onto the cylinder.

  Then, the development display means of the processing unit recognizes the intersection of the extracted polygon outline and the seam line LI, sets the position of the intersection as a new vertex position (orthogonal coordinates after projection), and uses the seam line LI as a boundary. After dividing the polygon and defining (recognizing) a new polygon, the cylinder is expanded and the map plane is displayed on the display unit. In the example of FIG. 6B, intersections P10, P11, P12, and P13 of the outline of the polygon PO1 having three vertices P0, P1, and P2 and the seam line LI become new vertices, and three polygons (polygon PO11, Polygon PO12 and polygon PO13). The x coordinate of P12 is a value obtained by adding 2πr to the x coordinate of P10, and the x coordinate of P13 is a value obtained by adding 2πr to the x coordinate of P11. Thus, for example, one side of the polygon PO11 constitutes the left side H1 of the map plane F, and one side of the polygon PO12 constitutes the right side H2 of the map plane F, so that the left and right sides H1, H2 of the map plane F Can be complemented in a straight line instead of a jagged outer shape.

  Next, a complementary algorithm for the upper and lower sides H3 and H4 will be described.

  In such a complementing algorithm, after the vertex position of the polygon is projected onto the cylinder as described above, the extraction unit of the processing unit causes the polygon (for example, a polygon that intersects the central axis of the cylinder among the plurality of polygons constituting the earth object) A polygon PO2 having vertices P3, P4, and P5 shown in FIG. 6A is extracted. In practice, two polygons on the upper and lower sides of the cylinder are extracted by such processing. Further, the three vertex coordinates of the extracted polygon are temporarily stored at a predetermined address in the RAM. The polygon can be extracted even before the vertex position of the polygon is projected onto the cylinder. This is because the central axis G of the cylinder T is the same as the axis G of the sphere.

  Subsequently, the specifying unit of the processing unit specifies the latitude and longitude of the intersection P6 between the extracted polygon and the central axis G of the cylinder T. For example, since the vertices P3, P4, and P5 of the polygon PO2 shown in FIG. 6A have latitude and longitude, the latitude and longitude of the intersection point P6 can be calculated and specified from these three vertices.

  The unfolding display means of the processing unit is a reference rectangular plane (that is, an ideal plane having straight upper, lower, left and right sides, and coordinates of the upper, lower, left, and right sides of the plane are defined and stored in advance. For all the points on the upper side that draw the image, the cylinder is expanded using the latitude and longitude of the intersection and the map plane is displayed. More specifically, in the example of FIG. 6B, new vertices P31, P32, P41, P51, P52 are defined on the upper side H3, and new vertices P33, P2 are also formed on the left and right sides H1, H2. P53 is defined. Here, the x coordinate of P32 is the same as the x coordinate of P3 (that is, P32 is defined vertically above P3), the x coordinate of P41 is the same as the x coordinate of P4, and the x coordinate of P51 is P5. Is the same as the x coordinate. These new vertices P31, P32, P33, P41, P51, P52, and P53 and the vertices P3, P4, and P5 of the extracted polygon PO2 are used to create a new polygon (of FIG. 6B). In the example, polygon PO21, polygon PO22, polygon PO23, polygon PO24, polygon PO25, polygon PO26, polygon PO27, and polygon PO28) are defined. The broken line indicates the outline of the polygon when not complemented. Further, illustration of other polygons is omitted.

  Thus, among newly defined polygons, one side of the polygon PO22, polygon PO24, polygon PO26, and polygon PO28 constitutes the upper side H3, and the vertices P31, P32, P41, P51, Since the latitude and longitude of the intersection point P6 (orthogonal coordinates after projection) are used for P52, all points on the side connecting P31, P32, P41, P51, and P52, that is, all points on the upper side H3 are the intersection point P6. The latitude and longitude (orthogonal coordinates after projection) are used. As a result, the upper side H3 of the map plane F can be complemented in a straight line rather than a distorted outer shape. The same applies to the lower side H4 of the map plane F.

FIG. 7 is a diagram showing a display example when a map plane is displayed using the above complement algorithm. The top, bottom, left and right sides of the map plane F shown in FIG. 7 are clearly displayed in a straight line.
[4. Altitude color determination algorithm]
Next, an altitude color determination algorithm according to this embodiment will be described.

  In the altitude color determination algorithm, instead of directly applying a texture image to the earth object, an altitude value is converted into image data and an rendering color is determined by a GPU fragment program at the time of rendering. Such a fragment program needs to use a color table (a color table defining a drawing color corresponding to an elevation value at each point constituting a planar earth map) that links an elevation value and a drawing color. It can be realized as a dimensional texture.

  FIG. 8 is a conceptual diagram showing the correspondence between elevation data and a color table. In the fragment program, as shown in FIG. 8, the elevation value of the pixel to be drawn is replaced with the texture coordinates for referring to the color table, and the calculation of the texture coordinates is performed dynamically.

  In other words, the expansion display means of the processing unit that operates according to the altitude color determination algorithm refers to the color table for the drawing color of the point corresponding to the orthogonal coordinate converted from the vertex position of the polygon when expanding the cylinder. The drawing color corresponding to the altitude value at the point is displayed. Further, the development display means of the processing unit calculates the orthogonal coordinates of a plurality of points inside the polygon on the map plane from the orthogonal coordinates corresponding to the vertex position of the polygon, and the point corresponding to the calculated orthogonal coordinates is calculated. The drawing color is displayed with the drawing color corresponding to the altitude value at the point with reference to the color table.

  The altitude color determination algorithm not only uses texture mapping directly, but also changes the drawing color dynamically by changing the offset value above sea level (the drawing color reference level according to the altitude value). It is said. More specifically, the change control means of the processing unit changes the offset value above sea level (for example, in the direction of the up and down arrows in FIG. 8) in accordance with an instruction (for example, an instruction by a mouse) via the input means from the user. The development display means of the processing unit changes the drawing color of the point on the already displayed map plane with reference to the color table every time the sea level offset value is changed. In other words, the elevation of each point seems to change substantially through the change in color due to the change in the offset value above sea level (actually, the elevation value does not change, and the drawing color reference changes). Become.

  FIG. 9 shows a display example when the sea level offset value is raised in the state where the map plane F shown in FIG. 7 is displayed, and the land level shown in FIG. It is expressed that it sinks under the sea surface. On the other hand, FIG. 10 shows a display example when the offset value of the sea level is lowered while the map plane F shown in FIG. 7 is displayed, and is not shown in FIG. 7 because the sea level is lowered. The land is now represented. In fact, since it is displayed in a color corresponding to the altitude value, the altitude can be easily grasped by the color even in the same land or the same sea.

  The unfolding display means of the processing unit displays the drawing colors of points corresponding to the points on the upper and lower sides of the map plane F supplemented by the upper and lower sides H3 and H4 when the cylinder is unfolded. As a drawing color corresponding to the elevation value at the point, the orthogonality on the map plane F corresponding to the vertex position of the polygon (polygon PO2 in the example of FIG. 6A) that intersects the central axis of the cylinder. Orthogonal coordinates of a plurality of points inside a new polygon composed of coordinates (in the example of FIG. 6B, polygon PO21, polygon PO22, polygon PO23, polygon PO24, polygon PO25, polygon PO26, polygon PO27, and polygon PO28). Is calculated from the Cartesian coordinates corresponding to the vertex position of the polygon that intersects the central axis of the cylinder, and corresponds to the calculated Cartesian coordinates. The drawing color of the point, by referring to the color table will be displayed in the foreground color corresponding to elevation values at the above point.

  As described above, according to the above-described embodiment, the user can arbitrarily specify the attitude of the earth, and the interpolation algorithm described above allows the right and left sides H1, H2 of the map plane F to have a jagged outer shape quickly and effectively. In addition, the contours of the upper and lower sides H3 and H4 of the map plane F can be complemented in a straight line quickly and effectively, giving the user a new perspective on the world. Interpretation and recognition of the difference between the map and the real world can be realized more effectively.

  Further, when the cylinder is expanded, the drawing color of the point corresponding to the orthogonal coordinate converted from the vertex position of the polygon is displayed with the drawing color corresponding to the altitude value at the point with reference to the color table. As a result, rapid processing is possible, and the user can be made to interpret the world from a new perspective.

  Furthermore, since the drawing color can be changed dynamically by changing the offset value above the sea level, the user can grasp, for example, how much land will sink below the sea level due to sea level rise due to global warming. be able to.

  In the present embodiment, the earth object is described as an example of the three-dimensional object. However, the present invention can be applied to other star objects and the like, or a process of developing a sphere on a plane.

It is a figure which shows the example of an algorithm structure of the earth map creation software which concerns on this embodiment. It is a figure which shows a mode that the vertex position of a polygon is projected on a cylinder by a normal projection method. It is a conceptual diagram which shows a mode that the cylinder on which the vertex position of the polygon was projected is expand | deployed. The example of a display of the earth object displayed in the globe mode is shown. The example of a display of the map plane displayed in map mode is shown. It is a conceptual diagram which shows the mode of a complementation when the cylinder which projected the vertex position of the polygon is expand | deployed. It is a figure which shows the example of a display when a map plane is displayed using a complementation algorithm. It is a conceptual diagram which shows the correspondence of altitude data and a color table. It is a figure which shows the example of a display at the time of raising the offset value of a sea level in the state where the map plane F shown in FIG. 7 is displayed. It is a figure which shows the example of a display when the offset value of a sea level is lowered in the state where the map plane F shown in FIG. 7 is displayed.

Explanation of symbols

OB Earth object T Cylinder F Map plane LI Seam line G Center axis PO1, PO11, PO12, PO13, PO2, PO21, PO22, PO23, PO24, PO25, PO26, PO27, PO28 Polygon

Claims (5)

Projection means for projecting a vertex position of the polygon on a cylinder in a three-dimensional object in which a sphere or a spheroid is represented by a plurality of polygons and the surface of the earth is represented on the surface;
An unfolding display means for unfolding the cylinder and displaying the plane while converting the vertex position of the polygon into orthogonal coordinates on the plane;
Storage means for storing a color table for defining a drawing color according to an altitude value at each point constituting a planar earth map;
With
The unfolding display means displays the drawing color of the point corresponding to the converted orthogonal coordinate in the drawing color corresponding to the altitude value at the point with reference to the color table when the cylinder is expanded. A three-dimensional object processing device. The three-dimensional object processing device according to claim 1,
The unfolding display means calculates the orthogonal coordinates of a plurality of points inside the polygon on the plane from the orthogonal coordinates corresponding to the vertex position of the polygon, and draws the drawing color of the point corresponding to the calculated orthogonal coordinates, A three-dimensional object processing apparatus, characterized by referring to a color table and displaying in a drawing color corresponding to an altitude value at the point. The three-dimensional object processing device according to claim 2,
A change control means for changing a reference level of the drawing color according to the elevation value according to an instruction from the user via the input means;
The development display means refers to the color table every time the reference level is changed, and changes the drawing color of the spot on the plane that has already been displayed. .   A three-dimensional object processing program for causing a computer to function as the three-dimensional object processing device according to any one of claims 1 to 3. Projecting the vertex position of the polygon in a three-dimensional object in which a sphere or a spheroid is represented by a plurality of polygons and the surface of the sphere is represented on a cylinder;
An unfolding display step of unfolding the cylinder and displaying the plane while converting the vertex position of the polygon into orthogonal coordinates on the plane;
Storing a color table that defines a drawing color according to an altitude value at each point constituting a planar earth map;
With
In the unfolding display step, when the cylinder is unfolded, the drawing color of the point corresponding to the converted orthogonal coordinate is displayed with the drawing color corresponding to the altitude value at the point with reference to the color table. A three-dimensional object processing method characterized in that