Tablet Calibrate

This command executes the routine to calibrate the digitizer tablet to a hardcopy drawing. There are two methods of calibration: Known Reference Points, and Drawing Scale with New Reference Points, which are explained in detail below. The Calibrate routine must be used prior to using the Digitize Contours command.

Please refer to Configure, General Settings and Digitizer Puck Layout for selection of the correct puck layout before proceeding. 

Tablet Calibration

Known Reference Points uses two known coordinates for reference points on the hardcopy drawing. When this option is selected, the fields for coordinate information activate. Enter the known northing and easting values for the reference points from the information on the hardcopy drawing in the appropriate fields and select the Pick button. Pick the points from the hardcopy drawing using the tablet. Carlson Civil saves the coordinates of the two reference points for future calibrations and displays them on the Tablet Calibration Dialog the next time it is accessed, so if you are working on the same drawing, you can use the Known Reference Points method with the saved coordinates to calibrate to your previous coordinates. For greater calibration accuracy, choose two points that are farther apart rather than closer together.

Drawing Scale with New Reference Points is very convenient when you don't know the precise coordinates of the entities on your hardcopy drawing. You must specify the drawing scale from the plan. This method establishes a coordinate system relative to the position of the plan on the digitizer board. In addition to the drawing scale, you are required to enter a random coordinate for the first reference point, the default coordinate is (1000,1000). You then select the Pick button and pick the point on the hardcopy drawing to assign the specified coordinate to. The routine will compute the coordinate of the second reference point that you pick based on the first point. The coordinates of these two reference points would be saved and will be display in the Tablet Calibration Dialog as Known Reference Points the next time you calibrate the tablet, so you can digitize the previous coordinates if you are working on the same drawing, even though you may have moved or rotated your drawing on the digitizer tablet.  

Tablet Calibration Dialog
Specify the Calibration Methods. If you select Drawing Scale method, enter the drawing scale and the coordinate of the first reference point. Otherwise enter the exact coordinates of the first and second reference points.
Pick first reference point: pick a point
Pick second reference point: pick another point

Pulldown Menu Locations: Surface >> Digitize Contours
Keyboard Command: digsetup
Prerequisite: Affix a drawing to your digitizer tablet. Have a digitizer board and a puck connected to your computer, correctly configured, and have Wintab driver installed. Select the puck layout in Configure.