WETMAAP Technique 2
Texas City/Virginia Point: Element 1

Technique 2: Manual GIS
Element 1: Making Feature Overlays

Materials:

1:24,000 1994 USGS Virginia Point Quadrangle

(3) 11"x 17" clear film overlay

drafting tape

Colored marker pens: Red, Blue (Sharpies), and Black (ultra-fine)

Exercise:

1. Use 1:24,000 scale USGS Virginia Point Quadrangle

2. Use clear film 11"x 17"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 _) on the overlay, one at each corner of the study site.

5. Trace the Primary and Secondary roads, in red on the overlay.

6. At the bottom of the overlay (in red) draw a short horizontal line and label beside it "1980 Shoreline.

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

7. Remove the "Roads" overlay.

8. Use a second 11"X17" clear film overlay.

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

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 the shoreline 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 "1994 Shoreline"

14. Remove the "1994 Shoreline" overlay.

15. Use the third 11"X17" clear film overlay.

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

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

17. Use a Black pen.

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

19. Trace the railroads in Black on the overlay.

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

21. Tape the "Railroads" and "1992 Shoreline", one on top of each other, over the railroads" 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.