To automatically find all similar symbols, you must make sure you are in Scanning for symbols mode. You can select Scanning for symbols mode from the Edit menu, or from the mode selection in the top left of the window.
You can only enter Scanning for symbols mode if your axes have been defined.
Start with properly selecting the symbol you want to scan for. To do this, first click in the center of a symbol, when the window size is set appropriate to the symbol size (in pixels). You can see the scan window as a box in the Zoom View.
Once you have clicked in the center of a symbol, a window will pop up showing a zoomed in version of the symbol. Here, you can modify the reference symbol until it looks good:
The symbol should appear with a black foreground color. If this is not the case, the symbol color detection failed and you will need to click with the right mouse button on a pixel that you are sure is part of the symbol. From the menu that pops up, choose to set that pixel as reference color.
You want to select a symbol that is free of other graphics, such a curve that goes through the symbol. If there is no such symbol, select the cleanest you see, and in the symbol window remove the parts that are not part of the symbol with the left mouse button. If there are larger areas, separate them from the symbol using the left mouse button. Then click with the right mouse button on the group of pixels you want to erase. Choose Erase connected pixels from the menu that pops up.
When you are ready to scan for symbols, press OK. ScanIt will analyze the image and after a short wait (press Esc to cancel) a window will appear. At the same time, symbols appear in your image.
Not all symbols can always be perfectly matched; if the shape deviates to much from the symbol initially selected or the symbol is obscured by other data in the image, the match will have a higher deviation. Drag the slider to the right to get more symbols, or to the left if too many items have been detected as a symbol that are not. The tickmarks at the bottom of the slider show the positions at which symbols will be accepted or removed. To remove the next symbol, click the arrow button on the left. To add the next symbol, click on the arrow button on the right. Click OK to accept.
See also: Defining your axes, Manual pick mode, Trace curve mode.