WETMAAP Technique 2
Cocodrie Element 1 

Technique 2:  Manual GIS
Element 1:  Making Feature Overlays

Materials:

            1994 1:24,000 scale  Lake Quitman-Cocodrie Topographic Quadrangle

            (3) 11"x 17" clear film overlay

            drafting tape

            Colored marker pens: Blue, Red, Black  

Exercise:  

            1. Use 1:24,000 scale 1994 Lake Quitman-Cocodrie Topographic Quadrangle

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

            3. Tape the clear film overlay on top of the 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 2) on the overlay, one at each corner of the study site.

            6. Trace the shorelines of Bayou Petite Caillou in Blue on the overlay.

            7. At the bottom of the overlay (in blue) draw a short horizontal line and label beside it “Bayou Petite Caillou.” 

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

            8. Remove the “Bayou Petite Caillou” 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 Black pen.

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

            13. Trace the primary and secondary roads in Black on the overlay.

            14. At the bottom (in black) draw a short horizontal line the same length as the Blue line and label it “Roads.” 

            15. Remove the “Roads” 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 Red pen.  

            19. Use the Red pen to make four “corner marks” (tick mark 2) on the overlay, one at each corner of the study site. 

            20. Trace the shoreline of the Houma Navigation Channel in Red on the overlay

            21. At the bottom (in red) make a dashed line and label it “Houma Navigation Channel.” Do not remove this overlay. 

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

            22. Tape the “Bayou Petite Caillou” and “Roads” overlays one on top of each other, over the “Houma Navigation Channel” 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 alignments. You have created a manual GIS.