The Polygonal Lasso Tool

                                         

     Polygonal Lasso Tool

1. In the Toolbox, select the Polygonal LassoTool.
2. Click on your image to set the first anchor point; then create a contour by adding anchors (clicking) in the key points.
3. When you come near the first anchor points it looks like this . Click to close the contour.
4. You can also double-click to close the contour at anytime and any point.
5. While the New selection option is chosen on the Options bar, you delete the existing selection by making a new selection. 
6. To add an area to the existing selection you have either to choose the Add to selection mode on the Options bar or to hold down [Shift] key while selecting. 
   
7. To subtract an area from existing selection you have either to choose the Subtract from selection option on the Options bar or to hold down [Alt] key while selecting.

8. To intersect a new selection with the existing selection, either choose the Intersect with selection mode on the Options bar or by holding [Shift+Alt] keys while selecting.
9. While the New selection option is chosen and the cursor is within the selected area the tool looks like this and can move the selection (ie. borders of the selected area and not the image content).
10. You can also move selection by using the keyboard cursor keys.