3D (3-dimension) mapping method for down-hole three-component magnetic measurement

The invention discloses a 3D (3-dimension) mapping method for down-hole three-component magnetic measurement. The 3D mapping method includes the steps of (1) simulating a work area: drawing a cube, establishing an END coordinate system used for drawing a borehole trajectory graph by taking the center point of the top surface of the cube as the origin; drawing a direction of magnetic north, a direction of a transverse section and a direction of a longitudinal section respectively according to a magnetic declination and a transverse section angle; and establishing an XYD coordinate system used for positioning magnetic anomaly points; (2) drawing borehole trajectory graph with E, N and D in the END coordinate system, wherein the E is an offset distance of the borehole trajectory in a direction to the east, the N is an offset distance of the borehole trajectory in a direction to the north, and the D is a true depth of the borehole trajectory; drawing a curve of delta Z, delta H , delta H// and delta H', and a vec