| 摘要 |
PURPOSE:To eliminate the need to change coordinate values at the time of a change of a surveying area by setting coordinate values from a zero base point and the inclination of the surveying area to an A axis together with contraction scale values by using the center point of the target surveying area. CONSTITUTION:The center point of a rectangular surveying area 14 which is planed previously is denoted as a surveying origin P and a zero base point based upon the surveying method or values X0 and Y0 from the zero base point 0 of local area coordinate systems X and Y and the inclination theta of the area 14 around an X0 axis clockwise or counterclockwise are supplied. Further, the extent of the necessary area 14 is given by contraction scale values Nx and Ny. Then, the values of the coordinate system detected by a ship position measuring instrument 4 are inputted to an arithmetic part 23 through an input/ output interface 8. The arithmetic part 23 converts ship position data into coordinate values of local coordinate systems XR and YR set by X0, Y0, and theta to find the position of its ship on the coordinate systems. On the other hand, the X0, Y0, and theta, and Nx and Ny are set and inputted previously by the arithmetic part 23 and those constants are processed on a screen to make a drawing on the screen 26.
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