Part 3—Launch My World GIS and Import Auburn Forest Inventory Analysis (FIA) Data
Step 1 Launch My World and Open the Maine Forest Project File
- 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, Maine_Forest.m3vz. Select it and then click Open.
When the project opens, a world map displays. It shows Elevation and Bathymetry with outlines of Countries overlaid on top. Layers not visible on the map include Maine Rivers, Auburn Forest Inventory Growth (FIG), Nokomis FIG, Major U.S. Highways, Biophysical Polygons of Maine, Maine Counties, Continents, and Lines of Latitude & Longitude.
Step 2 Zoom To the United States
- Select the Zoom In tool. Your cursor will now look like a magnifying glass with a plus sign in it.
- Click once on North America with the Zoom In tool.
- Click once on the Zoom to All tool
to take the map all the way back out to a full view.
NOTE: This is a nice trick if you get lost and just want to start over again. - Continue clicking on the map with the Zoom In tool. The tool automatically centers the zoom level on the area where you click. How far can you zoom in?
- Click the Zoom Out tool several times. Keep clicking. How far can you zoom out?
- When you are done exploring zooming, click the Zoom to All tool.
- Click and drag out a rectangle across the contiguous U.S. States with the Zoom In tool. Notice how this allows for more precise zooming.
- Click the Zoom to All tool to return to the full map view.
- Two other buttons help you navigate on screen. They are the Zoom to Previous Extents and Zoom to Next Extents buttons. Try zooming in and then experimenting with these buttons. The Zoom to Previous Extents button lets you go back to a previous level of focus. Both of these buttons give you unlimited zooms back and forth between levels.
- When you are zoomed in, you can use the Move Map tool to adjust your view. Click and hold the Move Map tool and drag your mouse to center your map on another place.
- When you are done exploring zooming, zoom to North America and use the Move Map tool to center the map on the United States.
As you zoom closer and closer on the image, you eventually see "pixels", or squares, of image data. However, most GIS data are vector-based, allowing you to continue to zoom in nearly infinitely.
Step 3 Locate the State of Maine, Zoom In and Explore State Data
Explore Active Layers
To the left of the map view is a listing of Layers, called the Layer List. In the Layer List, notice the checkbox to the right of the name of a layer. Click once in this box to turn a layer on and make it visible. Notice that when a layer is on, there is an eye in the checkbox.- Turn on U.S. States by clicking in the box next to its name. Layers that are on have an Eye in the checkbox.
- Notice that as you turn on a layer there is a legend for that Layer. To turn a legend on and off, click on the L symbol next to the words "Category List".
- Click anywhere in the box next to the name of a layer. The box will turn white and have a yellow highlight. This indicates that this layer is the Active layer. In the image below, U.S. States layer is the active layer and the Legend for the U.S. States is on.
- Make Countries active and click the Zoom to Active layer button. Your map will zoom out to the extent of this layer.
- Click on the Zoom to Previous Extents button and re-center your map on the United States.
- Make U.S. States the active layer and use the legend to find Maine.
When you click on the name of a layer, it is highlighted and becomes active, which tells My World GIS to pay attention to it. Understanding the difference between a layer that is turned on and one that is active can save you time and help prevent frustration. A layer may be on or off as well as active or not. Layers that are on have a checked box while layers that are active are highlighted white with a yellow border. More than one layer can be on but only one layer can be active.
- Make sure the Highlight Mode is set to Color Selected (Yellow). Click once on the name Maine in the Legend for the U.S. States. Maine will be selected and highlighted on the map.
- Click the Zoom to Selection button to zoom to the extent of the selection, Maine.
- Once you have zoomed in to Maine turn off the highlighting by clicking the All (highlighting off) radio button. (It is located in the Layer List under the layer name.)
- Turn off (uncheck) the Elevation & Bathymetry layer.
- Turn on the Maine Counties Layer.
- In the Layer List, select the Maine Counties layer by clicking and holding its name. Drag the Maine Counties layer up the list and place it above the U.S. States layers.
Each layer in a GIS builds the map. The data that make up the layers are shown as either points, lines, or polygons. These layers come from shapefiles, a standard GIS data format. (It is also possible to add images to a GIS as is shown here.) The layers are drawn from the bottom to the top as they appear in the Layer List. If not positioned properly, some layers may cover up others. In general, images and polygons should be placed at the bottom, while lines and points should be arranged near the top.
- Practice turning other Maine layers on and off, and moving them up and down in the layer list.
- When you are finished exploring, turn off (uncheck) Maine Counties. Then turn on Maine Cities.
- Choose File > Import Layer from File and locate the .csv file in the unzipped folder that you downloaded in Part 1. Single click to select the file, Auburn FIA.csv, and then click Open.
- The Import Text window checks that the Latitude and Longitude fields are correct, which they are, so click OK.
- A Window opens asking whether you want to overwrite the existing file. Choose "Save as a New File", rename the file "Auburn_FIA2", and navigate to the location where you are saving your data. Click Save. My World GIS imports the CSV file, places it on the map, and saves a copy in the My World "data" folder on your computer.
- The new data layer should now be visible on the map and in the Layer List. Make it the Active layer and click the Zoom to Active Layer button in the toolbar. The map now displays the Auburn FIA csv data in green dots. (Note: your color may be different as My World randomly assigns a color when it imports data.)
- Zoom to the group of dots on the map.
- Now that you have added the new data, choose File > Save Project As... and name your project Maine_Forest_Part_3, or some other unique name. Then click the Save button.
- If this is the end of the session, quit My World GIS.
Explore Moving Layers in the Layer List
Step 4 Import Auburn Forest Inventory Analysis (FIA) Data as a Layer
If you have trouble downloading data or saving the project file, then use this completed (and saved) project file.
Maine_Forest_Part_3.m3vz ( 17.6MB Jun30 10)
Right-click (PC) or control-click (Mac) the link above to download the file.
Maine_Forest_Part_3.m3vz ( 17.6MB Jun30 10)
Right-click (PC) or control-click (Mac) the link above to download the file.