Projection characteristics of cylinder

The projection characteristics of the cylinder are: on the projection plane parallel to the bottom, the projection of the cylinder is circular, and on the other two projection planes, the projection of the cylinder is rectangular.

Cylindrical projection is a kind of map projection. Assuming that a cylinder is tangent to the earth or tangent, take the cylindrical surface as the projection surface and project the longitude and latitude lines on the spherical surface onto the cylindrical surface. In the cylindrical projection of the normal position, the parallel line is the parallel line after the cylindrical surface is flattened, and the parallel line is the parallel line and orthogonal to the parallel line.

A projection with a cylindrical surface as the bearing surface. Suppose there is a cylinder wrapped around the earth, tangent to the surface of the earth, project the graticule onto the cylindrical surface, and then expand the cylindrical surface into a plane.

Similar to conical projection, cylindrical projection also has two cases of tangency or tangency. Mercator projection is one of the most commonly used cylindrical projections, which is usually tangent to the equator. Meridian is geometrically projected onto a cylindrical surface, while weft is mathematically projected.

This projection method generates a 90-degree latitude and longitude grid. The final cylindrical projection can be obtained by "cutting" the cylinder along any meridian. The warps are arranged at equal intervals, and the interval between the wefts increases as we approach the pole. This projection is an isometric projection, showing the true direction along a straight line. In Mercator projection, the constant line and the constant azimuth line are straight lines, but most great circles are not straight lines.

For more complex cylindrical projections, the cylinder will rotate, so the positions of the tangent and secant will change. Transverse cylindrical projection, such as transverse Mercator projection, takes the meridian as the tangent contact line or the line parallel to the meridian as the secant. In this way, the standard line is the line in the north-south direction, and the ratio above is true. Oblique axis cylinder is a cylinder that rotates around any great circle line between equator and meridian. In this more complex projection, most of the longitude and latitude lines are no longer straight lines.