How to draw an isobar map

Bathymetric Maps- Oceanography

Bathymetry is the measurements of water depths. One way to visualize the seafloor is by using a contour map. Contours are lines drawn connecting points of equal depth. It’s like “connect the dots” but with a twist. The lines are called isobaths, a line on a map that connects all points having the same depth below sea-level. Watch the first 6 minutes of this video, How to Draw Contours http://www.youtube.com/watch?v=L6FbV0LiA_k. The twist is that the depths for the isobaths may not be marked on the map; you’ll have to make an educated guess.

Looks like the boat captain didn’t finish drawing this bathymetric map. He managed to draw the 500-foot isobar. Draw the 485, 490, 495, 505, and 510 feet isobars.
contour line
Figure 1. Bathymetric map with the 500-ft contour line.
This map contains a bunch of soundings. Complete this contour map using a contour interval of 10 feet starting at 80ft, 90ft, ... to 130 ft. For now, ignore the line connecting points A and B.
contour lines to draw
Figure 2. Soundings map with points A and B.
Once you have drawn all the isobars, take the edge of a sheet of paper, and line it up with the gray dotted line. Mark the letters A and B on your paper. For every spot an isobar touches your paper, make a tick mark and write down the depth.
draw contour map
Figure 3. A pirate constructing a contour profile map of the ocean floor.
Take the sheet of paper, line it up with the graph paper and plot the depths on the graph below.

graph paper
Figure 4. A blank contour profile map.

How to Submit Your Task
Once you have finished the assigned task, submit Figure 1, Figure 2, and Figure 4.