Defining an NEZ coordinate system based on control points

If you will not be using a known control point with known transformation scale and angle for your locality, you could have these values computed based on two points: a Reference Point and a Control Point. It’s best to select these two points near the two opposite corners of your work site. You will need to obtain the coordinates for these same two points in the two different coordinate systems.

To do so, first tap the Control Point check box in the NEZ System screen of  the CMTINC.COM app that provides NEZ setup capability. The pull-down arrow on the same line of this option will show two modes: Reference Point and Control Point.

For each mode, enter the actual LLA values of the GPS coordinates of the point and the NEZ coordinates you wish to assign for the same point. The software will automatically fill the Angle and Scale fields with the computed values. (If you have survey-grade GPS, you could use it to get the LLA coordinates for these points.)

Save your settings, then return to Map View. When you tap on the map, you will see that the coordinates are now displayed in terms of the NEZ system.

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