(http://funnel.sfsu.edu/courses/gm309/F05/problems/OceanBeach/OceanBeach.Mapping.html)
(Due at the end of class Thursday, Nov. 10, along with beach profile plots created by other group members.
Worth 5% of course grade, shared by all group members)

Objectives

• Use Ocean Beach field measurements and observations to construct annotated plan view and side view maps of a portion of Ocean Beach and the cliff face behind it.
• Compare our observations with previous ones at the same site.

Introduction. On Tuesday, Nov. 1, we collected a variety of data from a stretch of San Francisco's Ocean Beach south of Sloat Ave. These data included measurements of distance along the top of the cliff behind the beach, relative to the north end of the second parking lot south of Sloat Blvd.; measurements of the distance between the edge of the pavement and the edge of the cliff; measurements of the height of the cliff; measurements of the width of the beach; qualitative observations and samples of materials in and on the cliff face and on the beach; and photographs of portions of the cliff face and other aspects of the beach. We now want to organize these data to facilitate comparisons with past and future observations from the same site.

Materials Needed

• data recorded during our Ocean Beach field trip
• 11"x14" or larger piece of paper
• ruler (either metric or English units will do)
• colored pencils (optional)
• calculator (e.g., on the laptops in the classroom, look in the Applications folder after double-clicking on the hard drive icon on the Desktop)

Your Tasks. Your first job will be to consolidate the data collected by different people working in different groups. Some of these data will be redundant, but some won't be, and having more than one person recording data tends to increase the quality of the data. Type up these diverse field notes into a coherent set.

One of your group members (the "expert" on geologic history of Ocean Beach) helped collect data from along the top of the cliff and another member (the "expert" on the near-shore environment) helped make and record observations from the cliff face. Those two group members should collaborate to construct the maps described below. You'll also need data (and possibly assistance) from the remaining group members, who helped record observations and collect samples from the beach.

1. Draw a "plan" or "map" view of the beach and terrace behind the cliff. (A plan or map view is a view from above, looking straight down.) The map should start with the assumption that the edge of the paved surfaces (the parking lot or Great Highway) behind the edge of the cliff lie along a straight line (an assumption that is not quite true and will distort the map, but we can live with that). The map should show (a) the edge of the cliff relative to the edge of the pavement and (b) the width of the beach relative to the edge of the cliff, both drawn to scale. (You can assume that the cliff is vertical for this purpose.)
   
   To show the variations in pavement-to-cliff distance and beach width clearly, you'll need to establish one distance scale for the direction parallel to the beach and cliff edge, and another scale for the direction perpendicular to the beach and cliff edge. (All measurements should be in feet. If your data are in meters, convert them to feet by multiplying by 3.28 feet per meter.) The map should fit onto one of the legal size (11"x14") or larger pieces of paper that we provide to you. The long side of the paper should be the direction parallel to the beach and cliff edge. The size of the paper, together with the range of distances recorded during the field trip in each direction, largely determine the distance scale that you should use.
   
   Once you've got the edge of the cliff and the width of the beach plotted to scale, you'll need to annotate the map. These annotations should include:
   
   
   1. The actual distances along the cliff top from the starting reference point to several landmarks. (The posts installed every 300 ft. along the beach and in some cases along the cliff top would be good choices.)
      
      
   2. The actual distances measured between the pavement and the cliff edge and from the cliff base to the average edge of the water (that is, the width of the beach at that particular point in the tidal cycle).
      
      
   3. Notable features and other non-quantitative observations, including photographs as appropriate.
      
      
   4. Locations of samples collected.
      
      
   You can indicate the locations of features and samples simply by numbering them on the map, and summarize the meaning of numbered locations on a legend (probably on a separate piece of paper). To mark the locations where photographs were taken you might use letters instead of numbers and prepare a separate photograph legend or appendix to which the letters refer. (Photographs should be captioned.)
   
   
   
   
   
   
   
   
   
   
   
   
   
   
2. Draw a side view map of the cliff face, looking directly at the cliff face. This map should use the same scale in the direction parallel to the beach and cliff edge as the previous map. It should start with the assumption that the bottom of the cliff is at the same level everywhere (an assumption not quite true and that will distort the map, but we can live with that). The map should show the top of the cliff relative to this (assumed) flat baseline. The distance scale in the vertical direction should be based on the width of the paper and the maximum height of the cliff measured during the field trip.
   
   Once you've got this cliff profile plotted to scale, you'll need to annotate the map. These annotations should include:
   
   
   1. Actual heights of the cliff wherever they were recorded. (You'll need to convert measurements recorded where the cliff was not very steep into a vertical distance. For 45 degree slopes, you can estimate the vertical height by dividing the measured distance from the top of the slope to the bottom by the square root of two, which is about 1.4.)
      
      
   2. Materials covering the cliff face, if any. (You can shade the cliff face on the map with different colors and symbols, such as dots, cross-hatching, etc., to distinguish among different materials.)
      
      
   3. Materials of which the cliff face is made (if visible beneath any covering materials).
      
      
   4. Notable features and other non-quantitative observations, including photographs as appropriate.
      
      
   5. Locations of any samples collected from the cliff face.
      
   
   
   As for the other map, you'll need one legend for annotations and symbols and another legend or appendix for captioned photographs.

Of course, both maps should be titled, and information about the authors and the date and time where the data were recorded should appear on it as well.

Finally, compare your group's maps, beach profiles, and observations with those recorded by GEOL./METR 309 field trips to Ocean Beach in previous semester(s), and note whether or not there seem to be significant changes over time that you can document.

Turn in your maps, beach profiles (assignment described in a separate document), consolidated and typed field observations, etc. as a single package for your group.