Identifying curves

The Curve identification tab is activated once the axis settings step is complete. You can then begin selecting data points to acquire data. The coordinates of the points that are generated are scaled using the values entered during the axis settings.

Adding points

Data points can be added continuously by selecting the Add points toggle button. After starting Add points mode, you see a crosshair highlighting the mouse position on the screen when hovering your cursor over the image. Click on the image to add points.

The coordinates of the added points are shown in the table on the left. The points are sorted in the table in the order of the click. Each click adds a new row to the end of the table. A polyline is drawn on the image to help you match the connected points to the curve and check the order of the points

Figure 3: Add points

If you want to select an exact position on the image, you can use the Arrow keys to adjust the mouse cursor position pixel-wise. Press Return to apply the data point of the selected position.

As in the Axis settings tab, you can toggle the magnifying glass by pressing Z on your keyboard or click the reticule button at the top right of the image view. The zoom view appears, delimited by a reticule shape. It helps you to improve the accuracy of pixel selection.

Note

If you see incorrect numbers in the table according to your graph, then perhaps incorrect axis scales were entered. You can switch to the Axis settings tab, change the settings and switch back to the Curve identification tab. The existing data points are kept, and their values are updated based on the new axis settings.

You can press Esc to exit Add points mode.

Edit existing points

You can reposition an existing point. Select the point, hold down the left mouse button and drag the point to a new position, or use the Arrow keys to adjust the position.

Press Return to apply the new position and release the selection, or right-click anywhere on the image.

The values of the data points are updated in the table once you release the left mouse button or when you press an Arrow key.

This feature is available whether the Add points toggle button is enabled or not.

Note

If the magnifier is enabled, the reticule of the zoom view turns blue to notify you that a point is selected.

Insert new points

You can insert a new point on a segment of the polyline. Hover your cursor over a segment and click on the line. A new point is created and remains selected.

A new row containing the values of the data point is inserted into the table between the rows of the data points that correspond to the ends of the segment.

This feature is available whether the Add points toggle button is enabled or not.

Note

When you hover the cursor over a segment, a plus sign appears to notify you that you can insert a point.

Delete points

You can delete an existing point. Select the point and click the Delete button on your keyboard.