The difference between central projection and vertical projection of photos

Central projection? The basic principle of aerial photogrammetry is perspective transformation of central projection, and the basic principle of stereo mapping is geometric inversion of projection process. The work of aerial photogrammetry is both outdoor and indoor. ?

The projection formed by light scattering from a point is called central projection.

1, the projection lines of the central projection intersect at one point.

2. A point light source illuminates a figure on a plane, and the shadow of this figure is its central projection on this plane. ?

3. The plane is the projection plane, and each ray is the projection line. ?

4. After the spatial figure is projected by the center, the straight line becomes a straight line, but the parallel line may become a straight line intersecting vertically. ?

5. Compared with the original picture, the figure after central projection has changed greatly, but it is intuitive and looks in line with human visual effect. ?

6. I like the original most, so I often use this method when drawing, but in solid geometry, I seldom use the principle of central projection to draw. ?

7. If the plane of the plane figure is parallel to the projection plane, the figure obtained after central projection is also parallel to the original figure, and the figure obtained after central projection is similar to the original figure.

Vertical projection is a geometric projection method used in plane map. The ground point is projected on the horizontal plane along the vertical line, and the plane position of the ground point on the horizontal plane is obtained, which constitutes the plane figure corresponding to the ground point. It is also a perspective rule widely used in painting creation art.

The length and area of the plane figure are smaller than the real object, and the deformation of the flat ground after horizontal projection is very small. It is often used in plans with a small scope and the influence of the curvature of the earth does not exceed the surveying and mapping error.