WETMAAP Technique 2
False River - Element 1

Technique 2: Manual GIS
Element 1: Making Feature Overlays

Materials:

1:24,000 scale 1962/1994 New Roads, LA / 1962/1980 Erwinville, LA,, USGS Topographic Quadrangles.

(3) 11"x 17" clear film overlay

drafting tape

Colored marker pens: Blue, brown, Orange

Exercise:

1. Use 1:24,000 scale 1962/1994 New Roads, LA / 1962/1980 Erwinville, LA,, USGS Topographic Quadrangles.

2. Use a clear film 11"x 17"overlay.

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

4. Use the Blue pen.

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

6. Trace the hydrologic features (streams and water bodies) in Blue on the overlay.

7. At the bottom of the overlay (in blue) draw a short horizontal line and label beside it "Hydrologic Features"

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

8. Remove the "Hydrologic Features" overlay.

9. Use a second 11"x 17"clear film overlay.

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

11. Use the Brown pen.

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

13. Trace the 35 Foot Contour with a Brown line on the overlay.

14. At the bottom (in Brown) draw a short horizontal line the same length as the Brown line and label it "35 Foot Contour"

15. Remove the "35 Foot Contour" overlay.

16. Use the third 11" x 17" clear film overlay.

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

18. Use the Orange pen.

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

20. Trace the 30 foot contour with an Orange line on the overlay.

21. At the bottom (in orange) make a small polygon and label it "30 Foot Contour" Do not remove this overlay.

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

22. Tape the "Hydrologic Features" and "35 Foot Contour" overlays one on top of each other, over the "30 Foot Contour" 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 otheroverlay 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.