Stream mode digitizing provides a quick and easy way to capture features on a paper map when you don’t require as much precision or when you’re digitizing smooth, curved lines—for example, rivers, streams, and contour lines. With stream mode, you create the first vertex of the feature and trace over the rest of the feature with the digitizer puck. When you’re finished tracing, you use the puck to complete the feature.

As you stream, ArcMap automatically adds vertices at an interval you specify; this interval, expressed in current map units, is called the stream tolerance. You can change the stream tolerance at any time, even while you’re in the process of digitizing a feature.

The group tolerance is the number of streaming vertices you want to group together. The number you set tells ArcMap how many vertices to delete when you click the Undo button. For example, if you set this number to 20 and click the Undo button while you’re digitizing a feature, ArcMap deletes the last 20 digitized vertices from your feature.

Press F8 to start digitizing in stream mode.

If you make a mistake while streaming, you can click the Undo button to remove the last group of vertices. You’ll need to press F8 to suspend streaming while you’re choosing interface elements, and press F8 again when you want to return to stream mode digitizing.