access canals throughout this area. These are the indicators of the rapid loss of land that has taken place over the past century in this area. As the vegetated marsh turns to open water, the protective buffer between the community and the Gulf of Mexico is reduced. Zoom in to Isle de Jean Charles to less than 500 m eye altitude. Observe the elevation of the ground as you mouse over the community. Note a levee that runs around the (does it completely surround the island?). Record the greatest and least “island” elevation of ground (not water). How high is the levee? What is the average elevation of the land, not counting the levee? height: Average land elevation: Zoom out so your eye altitude view is at 85 90 km. – Select the ruler icon at the top of the view. Select km. as your unit of map length (or ground length). Draw a line (directly N- S orientation) with your mouse between Isle de Jean Charles and Timbalier Island, directly south of the community. Record the distance. Distance from Timbalier Island to Isle de Jean Charles: Use the mouse to continue south out from Timbalier Island into the Gulf. Find the first location where the elevation is -10 m (10 m below sea level). Use the ruler tool to measure from this point to Isle de Jean Charles. Distance from -10 m to Isle de Jean Charles: Island Road, Isle de jean Charles. Photo Credit: Gary Allen. 2. Visualizing the Louisiana Coast in Cross Section: Calculating slope (example): Simple calculation: If a is located 1 km (1000 m) from the shoreline and is 1 meter above mean sea level, then the slope can be expressed as slope = rise/run = 1/1000 = .001 % If we were to draw this on graph paper and use a scale of: X axis: 1 square = 10 meters of horizontal distance so 100 squares = 1 km (1000m). Y axis: 1 square = .2 meters of vertical distance (5 squares = 1 meter) This slope can be expressed as a percentage or a decimal: Slope = Rise/run 1/1000 = 0.001
access canals throughout this area. These are the indicators of the rapid loss of land that has taken place over the past century in this area. As the vegetated marsh turns to open water, the protective buffer between the community and the Gulf of Mexico is reduced. Zoom in to Isle de Jean Charles to less than 500 m eye altitude. Observe the elevation of the ground as you mouse over the community. Note a levee that runs around the “island” (does it completely surround the island?). Record the greatest and least elevation of ground (not water). How high is the levee? What is the average elevation of the land, not counting the levee? height: Average land elevation: Zoom out so your eye altitude view is at 85 – 90 km. Select the ruler icon at the top of the view. Select km. as your unit of map length (or ground length). Draw a line (directly N- S orientation) with your mouse between Isle de Jean Charles and Timbalier Island, directly south of the community. Record the distance. Distance from Timbalier Island to Isle de Jean Charles: Use the mouse to continue south out from Timbalier Island into the Gulf. Find the first location where the elevation is -10 m (10 m below sea level). Use the ruler tool to measure from this point to Isle de Jean Charles. Distance from -10 m to Isle de Jean Charles: Island Road, Isle de jean Charles. Photo Credit: Gary Allen. 2. Visualizing the Louisiana Coast in Cross Section: Calculating slope (example): Simple calculation: If a is located 1 km (1000 m) from the shoreline and is 1 meter above mean sea level, then the slope can be expressed as slope = rise/run = 1/1000 = .001 % If we were to draw this on graph paper and use a scale of: X axis: 1 square = 10 meters of horizontal distance so 100 squares = 1 km (1000m). Y axis: 1 square = .2 meters of vertical distance (5 squares = 1 meter) This slope can be expressed as a percentage or a decimal: Slope = Rise/run 1/1000 = 0.001
Module8Formative-final.docx