Part 4—Prepare Data for Analysis
Step 1 Buffer Florida Interstate 10
- Launch My World GIS by double-clicking its icon on your desktop or by clicking its icon in the dock (Mac) or Launch Bar (PC).
- Choose File > Open Project, and navigate to the file, Wetlands_Part3.m3vz, that you either saved at the end of Part 3 or to the file that you downloaded at the end of Part 3. Select it and then click Open.
- Your map should be centered around the Florida Interstate 10 layer.
- To make a buffer around a line, first click on the Analyze tab, scroll down the list of options, and then click on Make Buffer Around....
In the panel to the right, make the following choices:
- Create Buffer of: Florida Interstate 10.
- Set the buffer at 15 Kilometers (about 9 miles).
- Click the radio button for Dissolve All Buffers.
- Name the result "15 km of Interstate". Click OK.
- A new layer is created for the 15 km buffer, and displayed on the map as 15 km of Interstate. Edit the appearance of the new layer to make the buffers transparent. Select the new 15 km layer by clicking on it, and then click on the Edit Layer Appearance
button just above the Layer List. In the window that opens, select the following options:
- Set Choose Fill Color by to Uniform and make it a yellow.
- Adjust the slider for Transparency to 80%.
- Change the Outline Color to Orange.
- Adjust Outline Width to a larger option.
- Click Apply and Close.
- Turn on the Valdosta Land Use layer, zoom in, and visually compare the pattern of land use data with the 15 km buffer around Florida Interstate 10.
- For now, turn off the new 15 km buffer around Florida Interstate 10 layer.
- Switch to Analyze mode and select all the wetlands in the Valdosta Land Use layer.
- Choose Select... > By Value.
- Select Records from: Valdosta Land Use.
- Whose: Land Use Contains 61 OR Whose: Land Use Contains 62 (Note: this will select BOTH sets of Wetlands). Note: to enable the "OR" selection criteria, you may need to click on the (+) button.
- Check Make Selection a New Layer.
- Name your new layer "Forested and Non Forested Wetlands", and Click OK.
- The wetlands will now be on your map, you may decide to edit their appearance to be less transparent.
- Turn off (hide) the original Valdosta Land Use layer.
- Next, use My World to create a buffer around the all the wetlands in the study area. In general, wetlands are protected by a 100 meter buffer around each wetland.
- To make a buffer around a polygon, first click on the Analyze tab, scroll down the list of options, and then click on Make Buffer Around....
In the panel to the right, make the following choices:
- Create Buffer of: Forested and Non-Forested Wetlands.
- Set the buffer at 100 meters.
- Check: Outside, with interior.
- Click the radio button for Don't Dissolve All Buffers.
- Name the result "100 meters of Wetlands". Click OK. This analysis process may take several minutes, there are a lot of wetlands!
- Once the buffer layer is complete and on the map, edit its appearance to be transparent with an orange outline.
- In Part 5, your final task is to select an optimal area for the proposed development. Begin the process by looking for areas that are:
- Outside of any 100 meter buffer of a wetland.
- Within the 15 kilometers of either side of Florida Interstate 10.
- Within 100 kilometers of the town of Macclenny, Florida.
- Use the Zoom and Pan tools to examine the area bounded by the Florida Interstate 10 buffer. Turn layers on and off as needed. What do you look for that makes a good development site? In general, you probably are looking for an area that is away from any wetlands and near a service road (as seen from your topographic map).
- Now that you have added the new data, choose File > Save Project As... and name your project Wetlands_Part4, or some other unique name. Then click the Save button.
- Quit My World GIS.
Step 2 Select and Buffer the Wetlands
Wetlands are important both ecologically and economically. They provide services such as flood control and groundwater recharge. They also serve as filters for both sediment and pollution. The wetlands in Florida are some of the most productive wetlands in the United States, recharging major underground aquifers and providing the cleanest water in the nation. While performing these essential services, they also provide habitat for many species of animals such as deer, raccoons, and salamanders. In addition to providing permanent homes for some animals, wetlands serve as important stopover points for millions of migratory birds as they travel between their summer and winter residences.
Over the past 100 years, many wetlands have been destroyed by human actions. Agricultural drainage creation, the deposition of fill materials and stream channelization dredging have all contributed greatly to this loss. Florida, and many other states in the Southeastern U.S., have lost as much as 50% of their original wetland area since the 1780's.
Because of their importance, federal legislation now limits the loss of wetlands and promotes restoration and conservation of formerly degraded wetlands. Laws now protect wetlands, which prevents existing wetlands from being converted to other uses without special permits. In order for wetlands to remain healthy and to function properly they need to be buffered from development by at least 100 meters, (330 feet). Use the Buffer tool to set a 100 meter buffer around the wetlands in this area.
Step 3 Examine the Map and Consider Options for Development
Step 4 Save the Project File and Quit My World
Wetlands_Part4.m3vz ( 25.6MB Oct11 10)
Right-click (PC) or control-click (Mac) the link above to download the file.