Generally, it is expressed in meters, indicating the relative position of the point from the origin of coordinates, but the commonly used coordinates are slightly different. The abscissa is the y coordinate and the ordinate is the x coordinate.

The main function of building general plane coordinates is to calibrate the relative position between buildings in the plane and the relative position relationship with other buildings or reference objects outside the plane. ?

There are generally two kinds of coordinates used in the general construction plan: the building coordinate system and the survey coordinate system, both of which belong to the plane coordinate system and are expressed in the form of grid. ?

The building coordinate system is generally a coordinate system made by the designer himself. Its origin is determined by the designer, and its two axes are represented by A and B respectively. The survey coordinate system is associated with the national or local survey coordinate system, and the two axes are represented by X and Y respectively. If there are two kinds of coordinate systems in the general plan, the conversion formula between them should generally be given. ?

The reading method of coordinates in the general construction plan is the same as that in the plane coordinate system in mathematics. For example, if we know the coordinates of four corners of a building (usually two or three diagonal points are given), we can calculate its length, width or distance from other buildings by calculating the triangle relationship. ?

However, it is particularly important to note that the X-axis direction of the measuring coordinate system is north-south, pointing to the north; Y axis is east-west, pointing to the east. That is to say, in the plan view, the coordinate axis in the horizontal direction is the Y axis, and the coordinate axis in the vertical direction is the X axis.