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coordinate transformation

Location description of spatial entities
Coordinate transformation is the description of the location of spatial entities and the process of transforming from one coordinate system to another. This is achieved by establishing a one-to-one correspondence between the two coordinate systems. It is an essential step to establish the mathematical basis of maps in the surveying and mapping of various scale maps. When two or more coordinates are converted, the dimension space is determined by relative reference to polar coordinates.
Chinese name
coordinate transformation
Foreign name
coordinate transform
Discipline
mathematics
Field
geometry
Basic transformation
Translation, magnification, rotation, shear, reflection
Research space
2D, 3D

meaning

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There are five kinds of coordinate transformation. Except for translation, the coordinate origin is taken as the reference point, that is, the coordinate origin remains unchanged before and after transformation.
The Chinese and English names and matrix Description. [1]

Basic transformation

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Multidimensional view

two-dimensional
one
zero
zero
zero
one
zero
x
y
one
three-dimensional
one
zero
zero
zero
zero
one
zero
zero
zero
zero
one
zero
x
y
z
one
[1]

Doubler

scale
two-dimensional
x
zero
zero
zero
y
zero
zero
zero
one
three-dimensional
x
zero
zero
zero
zero
y
zero
zero
zero
zero
z
zero
zero
zero
zero
one
[1]

rotate

Rotate: Take counterclockwise rotation as an example. Then the transformation matrix from the old coordinate to the new coordinate is
two-dimensional
[cos(θ) sin(θ)]
[-sin(θ) cos(θ)]
three-dimensional
Around Z, around Y, around X
▏cos(θ) -sin(θ) 0 0▕ ▏cos(θ) 0 sin(θ) 0▕ ▏1 0 0 0▕
▏sin(θ) cos(θ) 0 0▕ ▏ 0 1 0 0▕ ▏0 cos(θ) -sin(θ) 0▕
▏ 0 0 1 0▕ ▏-sin(θ) 0 cos(θ) 0▕ ▏0 sin(θ) cos(θ) 0▕
▏ 0 0 0 1▕ ▏ 0 0 0 1▕ ▏0 0 0 1▕ [1]

shear

shear
two-dimensional
Along X axis along Y axis
▏1 k 0▕ ▏1 0 0▕
▏0 1 0▕ ▏k 1 0▕
▏0 0 1▕ ▏0 0 1▕
three-dimensional
Along X axis along Y axis along Z axis
▏1 k l 0▕ ▏1 0 0 0▕ ▏1 0 0 0▕
▏0 1 0 0▕ ▏k 1 l 0▕ ▏0 1 0 0▕
▏0 0 1 0▕ ▏0 0 1 0▕ ▏k l 1 0▕
▏0 0 0 1▕ ▏0 0 0 1▕ ▏0 0 0 1▕ [1]

reflex

Reflect: The essence of reflection transformation is negative magnification, which is actually called "mirror".
two-dimensional
Based on X axis Based on Y axis
▏1 0 0▕ ▏-1 0 0▕
▏0 -1 0▕ ▏0 1 0▕
▏0 0 1▕ ▏0 0 1▕
three-dimensional
Based on Y-X plane Based on X-Z plane Based on Z-Y plane
▏1 0 0 0▕ ▏1 0 0 0▕ ▏-1 0 0 0▕
▏0 1 0 0▕ ▏0 -1 0 0▕ ▏0 1 0 0▕
▏0 0 -1 0▕ ▏0 0 1 0▕ ▏0 0 1 0▕
▏0 0 0 1▕ ▏0 0 0 1▕ ▏0 0 0 1▕
The coordinate transformation based on any plane can be regarded as the mapping of two linear spaces [1]

Application type

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Plane analytic geometry

In plane geometry, there are Cartesian coordinates Translation and rotation, as well as mutual transformation between polar coordinates and rectangular coordinates.
In the rectangular coordinate system, the translation of coordinates focuses on Relative coordinate And absolute coordinates. The translation of coordinates is determined by Axis Caused by the translation and rotation of. If we can find out Chuyuan The moving distance, moving direction and turning angle of the coordinate (before moving relative to the original coordinate). Then the required coordinates can be found in the new coordinates by performing the same transformation as the original coordinates.

Cartographic mathematics

stay Geographic Information System In, there are two kinds of coordinate transformation, one is Map projection Transformation, that is, from one map projection to another, the coordinates of each point on the map change; The other is coordinate transformation of the measurement system, that is, from Geodetic coordinate system To map coordinate system Digitizer Coordinate system graph plotter Coordinate conversion between coordinate systems or display coordinate systems.

measure

During the construction of the project, due to the use of different coordinate systems, coordinate transformation between different coordinate systems is required.