1, indicating the geographical location with coordinates. 2. Coordinate translation. The vertical axis is the X axis, and the upward (north) direction is positive; The horizontal axis is the Y axis, and the right (east) is positive; The angle (azimuth) is measured clockwise from the positive direction of the X axis, and the quadrants are also numbered clockwise.

1, axis has different meanings.

The measuring coordinate system takes the north-south line passing through the origin as the ordinate axis and the X axis; The east-west line passing through the origin is the abscissa axis, designated as the Y axis; The abscissa axis of the mathematical coordinate system is the X axis, and the ordinate axis is the Y axis.

2. Coordinate quadrants are stipulated differently.

The measurement coordinate system is also different from the mathematical rules of coordinate quadrant. Both of them take the northeast as the first quadrant, but the four quadrants in mathematics increase counterclockwise, while the measurement increases clockwise.

3. The coordinate point numbers are different

The coordinates (y, x) of the origin o of the survey coordinate system are mostly two large positive integers, such as the coordinates of the origin of Beijing local coordinate system, y = 500,000 m, x = 300,000 m; The coordinates of the origin of mathematical coordinates are generally similar to x = 0 and y = 0.

Extended data:

In rectangular coordinate system, any point on the plane corresponds to a unique ordered number pair; Conversely, for any ordered number pair, there is a unique point on the plane corresponding to it.

For any point C on the plane, the intersection point C is perpendicular to the X-axis and Y-axis respectively, and the corresponding points A and B perpendicular to the X-axis and Y-axis are called the abscissa and ordinate of the point C respectively, and the ordered pair (A, B) is called the coordinate of the point C. A point is in different quadrants or coordinate axes, and the coordinates of the point are different.

Coordinate characteristics of special position points:

1, and the ordinate of this point on the X axis is zero; The abscissa of a point on the y axis is zero.

2. If the abscissas of any two points are the same, the connecting line of the two points is parallel to the longitudinal axis (the abscissas of the two points are not zero); If the vertical coordinates of two points are the same, the connecting line of the two points is parallel to the horizontal axis (the vertical coordinates of the two points are not zero).

3. Distance from point to axis and origin:

The distance from the point to the X axis is | y | The distance from the point to the Y axis is | x | The distance from the point to the origin is the arithmetic square root of the square of x plus the square of y.

quadrant

The first quadrant can also be written as I, the second quadrant as II, the third quadrant as III and the fourth quadrant as IV.

The horizontal and vertical coordinates of the points on the bisector of the first quadrant and the third quadrant are equal; The horizontal and vertical coordinates of the points on the bisector of the second and fourth quadrants are opposite to each other.

symmetry point

1. The coordinates of the points symmetrical about the X axis have the same abscissa and the opposite ordinate. (horizontal and vertical)

2. With regard to the coordinates of points symmetrical about the Y axis, the ordinate is the same, and the abscissa is the opposite number. (horizontal and vertical)

3. With regard to the coordinates of a point whose origin center is symmetrical, the abscissa and abscissa are reciprocal, and the ordinate and ordinate are reciprocal. (Horizontal and vertical directions)

Baidu Encyclopedia-Plane Cartesian Coordinate System