WETMAAP Technique 2
Mobile Bay: Fresh Water Inflow Element 1

Technique 2: Manual GIS
Element 1: Making Feature Overlays

Materials:

1:24,000 USGS Map
(3) 11"x17" clear film overlay
drafting tape
Colored marker pens: Red, blue, black

Exercise:

1. Use 1:24,000 scale USGS Map

2. Use clear film 11"x17"overlay (large)

3. Tape clear film overlay on top of 1:24,000 scale map. Tape at the top edge.

4. Use the red pen to make four "corner marks" (tick mark – make one) on the overlay, one at each corner of the study site.

5. Trace only the Interstate in Red on the overlay.

6. At the bottom of the overlay (in red) draw a short horizontal line and label beside it "Interstate."

Hint: Use of a symbol with a short description beside it is a "key," or means of identifying selected features.

7. Remove the "Interstate" overlay.

8. Use a second 11x17"clear film overlay

9. Tape clear film overlay on top of 1:24,000 scale map. Tape at top edge.

10. Use the blue pen

11. Use the Blue pen to make four "corner marks" (tick mark) on the overlay, one at each corner of the study site.

12. Trace only the state highways in Blue on the overlay

13. At the bottom (in blue) draw a short horizontal line the same length as the red line and label it "State Highways."

 14. Remove the "State Highway" overlay

15. Use the third 11x17" clear film overlay

16. Tape clear film overlay on top of the 1:24,000 scale map. Tape the top edge.

17. Use the black pen

18. Use the Black pen to make four "corner marks" (tick mark) on the overlay, one at each corner of the study site

19 Trace only the streets n black on the overly

20. At the bottom (in black) draw a short horizontal line the same length as the red and blue lines and label it "Streets." Do not remove this overlay

Hint: Combining several single "key" items creates a "legend." Every map should have a legend

21. Tape the "State Highway" and "Interstate", one on top of each other, over the "Street" overlay. Use the four corner marks to line-up (‘register’) the overlays on top of each other.

Hint: Tape one overlay at the bottom edge and the other overlay at the left or right edge. By attaching the overlays at opposite edges, you can flip the overlays up and down in various alignment. You have created a manual GIS.