WireCAD ENT Tools Manual > ENT Basics > GPS Mapping Tools > Using Your DWG Drawings as Maps > How To: Calibrate (Geo-Reference) Your DWG to the GPS Coordinate System

Prerequisites

This topic assumes that you have a scaled drawing of your plant.

Further that there exists in the drawing two control points. Control points are typically survey markers for which you have the GPS coordinate data. However, they can be any geometry in your drawing such as the corners of buildings or manhole covers as long as you have reliable GPS data for that point.

Procedure

1.Open your plant or campus drawing. If the your plant drawing is very large you may want to consider Externally Referencing (XREF) it into a new drawing. This is done to keep the save operation lightweight. Externally referenced drawings do not get saved, only the base drawing.

2.Click Mapping Tools > GPS > Calibrate.

3.You will be prompted in the Command Prompt to pick the first point, or lower left point, from the drawing. Do so.

4.Enter the GPS point data for the lower left point. The control point does not necessarily have to be the lower left corner. We just need points opposite.

Please note that the coordinate is expected in decimal lat,lon form. Do not Crtl+V to paste your coordinate data as this will initiate the paste function in the drawing not the command line. Use the Right-Click context menu and select Paste there.

5.Pick the upper right point in the drawing.

6.Enter its GPS coordinate.

When done the drawing will display GPS in the lower right-hand corner to indicate that it is calibrated.

You will be able to use the GPS tools to pick location points from the drawing.

The statusbar text will show you the GPS coordinate of the current cursor position.

Once the drawing is calibrated you can use the Mapping Tools > GPS > Show Calibration Marks tool to place a marker in the drawing at your calibration points.