
The Data Reader and Screen Reader Tools
Use the Data Reader tool to read the X, Y, and Z (for 3D and contour) coordinate values for a data point. Use the Screen Reader tool to read the X,Y, and Z coordinates (contour only) at any location on the graph page.
Using the Data Reader tool
- Click the Data Reader button
on the Tools toolbar. This opens the Data Display tool (if it is not already open).
- Click on a data point to read its X,Y, and Z coordinates (3D or contour). Coordinate values display in the Data Display tool.
- To move the cross-hair to the next data point along the data plot, use the left and arrow keys or click on the data point using your mouse.
- To change the vertical and horizontal cross hair size after clicking on a point, press the spacebar. Continue pressing the spacebar to further increase the size of the cross hairs.
- Click the Pointer button
on the Tools toolbar when you are finished with the Data Reader tool.
| Hint: The initial selection of a point in a 3D surface or contour plot is sometimes difficult. It generally helps to click on a grid intersection point. Once you have selected a point, you can use the four arrow keys to maneuver over the surface or contour plot to read other points.
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Refining the data point search behavior of the Data Reader tool
When you click on a data plot with the Data Reader tool, Origin begins searching for the nearest point by one of two methods. Which method is used depends upon the number of points in the data plot and the Bisection Search Points combination box value on the Miscellaneous tab of the Options dialog box (Tools: Options):
- When the number of points is less than the Bisection Search Points value, then a sequential search is used.
- When the number of points is greater than the Bisection Search Points value, then a bisectional search is used.
A bisectional search can find the nearest point rapidly, but it only works if the X data are sorted. The middle point of the data set is tested first to determine which half contains the nearest point. This half becomes the new search set. If the X data set is not sorted, then this search scheme fails and you get a 'beep error' (Actually a few points will be found this way purely by chance).
If you discover that the X data are unsorted, you can do one of two things:
- Sort the source worksheet on the X column.
- Set the Bisection Search Points combination box to a value larger than the total number of data points to 'turn off' bisectional search.
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Note: When you use the Data Reader tool to view the coordinates of a data point in a graph, Origin displays the actual X and Y data values for the data point, not the displayed worksheet values. For more information, see Numeric Formats in Origin.
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Using the Screen Reader tool
- Click the Screen Reader button
on the Tools toolbar. This action opens the Data Display tool (if it is not already open).
- Click on a location in the graph page to read its X,Y, and Z coordinates (contour only). Coordinate values display in the Data Display tool.
- To increase cross hair size, press the spacebar.
- Click the Pointer button
on the Tools toolbar when you are finished with the Screen Reader tool.