The Create Calibration Points dialog is part of the Tablet Calibration Wizard. In the Create Calibration Points dialog, enter the World X and World Y coordinates for the calibration points you select. After the values are input, click on the tablet at these locations to define the correspondence between the source document coordinates and the digitizing tablet coordinates.
At least three calibration points must be entered. Depending on which georeference method is selected, additional points can be added. Calibration points cannot be in a straight line (collinear). In addition, an optional ID for each point can be entered to help identify the points as each is calibrated.
Enter the calibration points World X and World Y coordinates.
Click on the points to have Didger enter the Tablet X and Tablet Y coordinates.
To enter calibration points:
Position the puck's cross hair over the place on the paper source document where you want to define a calibration point.
Click the puck's digitize button (usually button 1). The tablet coordinates for that point are filled into the Tablet X and Tablet Y columns.
Assign the fields in the data file to the calibration points field.
Click in the Point ID box and type the ID for this calibration point. The ID is optional.
Click in the World X box and type the document's X coordinate for this calibration point.
Click in the World Y box and type the document's Y coordinate for this calibration point.
Click the Add Point button to create a new row in the calibration points table. The new row is automatically highlighted.
Repeat steps 1-4 for each additional point.
If one or more of the calibration points needs to be changed, click on the row in the calibration points table. Place the puck over the calibration point, and click the puck's digitize button. The new tablet coordinates are written to the calibration grid.
Click the Add Point button to add a new row to the calibration points table. Each row is a single calibration point.
Rows can also be added by clicking the Cancel button on the puck. Normally, this is button 3.
To remove a calibration point, click on the row in the calibration points table and click the Delete Point button.
The Load button imports coordinates for a previously defined set of calibration points. The calibration points can be stored in any supported data file format, including .XLS, .TXT, .XLSX, .DAT, or .ACCDB. Loading a previously defined set of calibration points saves time by not needing to type in the coordinates for a project that have bene previously defined. This works extremely well with a tablet when the paper document on the tablet has not moved.
Click the Load button to open the Open dialog. Select the data file and click Open. In the Load Calibration Points dialog, set the columns to the appropriate fields from the calibration points table and click OK.
To use previously defined calibration points:
In the Create Calibration Points dialog, click the Load button.
In the Open dialog, click on the data file containing the calibration points and click Open.
In the Load Calibration Points dialog, set the columns to the appropriate fields from the calibration points table. Click OK.
Back in the Create Calibration Points dialog,
If the document has not moved on the tablet, accept the previously calibrated points locations.
To relocate points on the document, click on the row and click on the appropriate point on the document.
Add additional calibration points, if desired, by typing the coordinates into the calibration grid and digitizing the added points.
Delete existing calibration points by clicking on the row and clicking the Delete Point button.
Click the Save button to open the Save As dialog. Type a File name and click Save to save the calibration points to a file. The Point ID, Tablet X, Tablet Y, World X, and World Y values are stored in the data file. This file can be used later to load the calibration points in this project or another project.
If the box next to the Activate Tablet option is checked, the tablet is ready to digitize the calibration points. If the box next to the Activate Tablet option is not checked, the puck can be used as a mouse. For example, you can click on the Next button when Activate Tablet is not checked.
Calibration points are added by clicking the Digitize button on the puck. Normally this is button 1.
Moving to the next row can be done by clicking the Finish button on the puck. Normally this is button 2.
Rows can also be added by clicking the Cancel button on the puck. Normally, this is button 3.
Check the box next to the Auto Advance Row Position option to automatically move to the next row when clicking on calibration points. When checked, after clicking on a point on the tablet with the puck, the next point is automatically highlighted. When unchecked, the point just selected remains highlighted in the calibration points table.
Moving to the next row can also be done by clicking the Finish button on the puck. Normally this is button 2.
See Also