Downloading and Installing Google Earth

Transcription

1 Google Earth is a GIS software package that can be used to view aerial photography and other data. Although its data analysis capabilities are less powerful than other GIS software, it is relatively simple to use, free to download, and provides simple access to a wealth of aerial photography, street side photography, 3D imagery, and other data maintained by Google. In addition to the imagery and data installed natively in Google Earth, customized information can also be represented. This data is saved in either.kml or.kmz files. For normal operations, the file formats are essentially equivalent. The z in.kmz simply indicates that a.kml file has been zipped to reduce the size. Downloading and Installing Google Earth Google Earth software can be downloaded from Google free of charge, subject to the restrictions in their Terms of Service and licensing. Although multiple versions are available, it is recommended that you download Google Earth Pro. Previously, a $400 annual subscription was charged for this version, It can now be licensed free of charge using your address and the key GEPFREE to sign in, as noted in the top-right area of the download website: Once the software is downloaded, run the executable file and follow the prompts for installation. Navigating in Google Earth When Google Earth opens, you will see a globe of the Earth. To start your search, type an address in the search bar in the upper-left corner of the screen and then press Enter. The screen will fly in to the location you entered, as shown in Figure 1. You can also enter latitude/longitude coordinates, place names or even parcel numbers.

2 Page 2 of 7 Figure 1: Locating an address in Google Earth The easiest way to navigate on the screen is with a mouse that has a wheel. By default, 3D Buildings are shown. This, and other information, can be turned on and off via the layers menu in the bottom left area of the window. Common navigation commands using the mouse are: Double-Click Click and Drag Scroll Wheel Up Scroll Wheel Down Wheel Button Drag (press down on the mouse wheel and hold) Zoom in at the location of the click Pans the view in the window Zoom in at the location of the cursor Zoom out at the location of the cursor Pan in 3-dimensions. In many metropolitan areas, 3D views are available that show dramatic 3D rendering. In other areas, rendering is based on ground topography. Figure 2, below, shows example 3D imagery in Columbus, Ohio.

3 Page 3 of 7 Figure 2: Example 3D imagery of Columbus, Ohio

4 Viewing Historical Aerial Photography Google Earth Primer Page 4 of 7 In most areas of the country, historical aerial photography is available that may go back to the 1990s or earlier. This is accessible by clicking on the clock-like icon in the upper toolbar (see Figure 3). A time bar will appear allowing you to step back through the years of imagery available. You will likely want to turn off 3D buildings when looking at historical imagery. When viewing the imagery, note that the exact date of the image is shown at the bottom of the screen (if this is not visible, turn off 3D buildings and hover your cursor over the aerial image). These dates are more precise than those given on the time bar. However, accuracy sometimes varies by a few days. Figure 3: Historical Aerial Imagery

5 Street View and Ground Level View Google Earth Primer Page 5 of 7 On the right-side of the screen is a compass and navigation tools for zooming and orientation. When you hover over these, you will see a little orange man (Figure 4). When you drag him onto the image, blue lines will appear where Street View is available. When you release him, the view will change to the Street View (Figure 5). The Street View imagery is gathered by Google s Fleet ( You may occasionally see their cars driving around with cameras, GPS and survey equipment mounted on their roof. They also have backpacks, bicycles, snowmobiles and carts they use to survey everything from canyons to museums. If Street View is not available, you will instead enter Ground-Level View which shows an overlay of aerial photography on surface topography (Figure 6). Figure 4: Entering Street View To exit Street View or Ground View, click the button in the top-right corner of the screen. You may occasionally need to rotate the display by holding down the mouse wheel button and dragging upward to re-orient the image.

6 Page 6 of 7 Figure 5: Street View Figure 6: Ground-Level View

7 Page 7 of 7 Viewing.kml and.kmz Files If you are provided a.kml or.kmz file, simply save it to an appropriate location on your computer and then double-click it to open. You can also open files through the File menu within the Google Earth application. Once open, you will see the contents of the file in the panes on the left of the window. These typicall appear under the Temporary Places folder, although when you exit Google Earth you may be prompted to also save them in the My Places folder. By saving them in My Places, they will be available every time you open Google Earth. Double-clicking on a feature will pan and zoom the map to that feature. Checking boxes next to the feature will either hide the features or make them visible. If you cannot see the features, click the small triangles to the left to expand the folder (Figure 7). There are a host of other features and layers available in Google Earth that can also be explored and turned on and off. Figure 7: Viewing.kmz files K:\CCA\Nate\Google Earth Memo.docx