This preview shows page 1. Sign up to view the full content.
Unformatted text preview: he outer perimeter in feet, (2) the
surface area in acres, (3) the elevation in feet, and (4) the outlet latitude/longitude coordinates in decimal
degrees for the three lakes. Despite the age of the original topographic map (1955), the Ophir USGS
topographic quadrangle will be used. Follow the steps below…
1. Start Internet Explorer, and go to the USGS Store website at http://store.usgs.gov. Click on the
Map Locator & Downloader link. In the next web page, type Ophir, Colorado in the Search box
and then click the Go button.
2. The red marker symbol
is on the “town” of Ophir and within the rectangular boundary of the
Ophir 7.5 minute USGS topographic map. If you zoom out one level, you can see this a little
more clearly. Left-click on the red marker symbol. A popup listing of the digital maps that cover
the town of Ophir are shown. Scroll down through the listing and find the 17.6MB link for the
1955 map. In the yellow box below the web page, click Save As. Save the .zip to your lab9
folder on the M: drive. The file will take a couple of minutes to completely download. Click the
View downloads button to track its progress. Once the file is completely downloaded and saved,
open it. Extract the contents of the .zip archive, a single PDF file named
CO_Ophir_233994_1955_24000_geo.pdf, into your lab9 folder.
3. Open Windows Explorer, browse into your lab9 folder, and double click on the PDF file that you
just downloaded and unzipped. Once Adobe Reader has started, open the Ophir PDF file that you
just downloaded. Set the Adobe Reader window to exactly ½ of the monitor width (left click, hold,
and drag the title bar into the upper left or right corner of the screen and then release).
This file is not your average-joe PDF file. It’s a GeoPDF! This type of PDF file is georeferenced,
and with the TerraGo Toolbar installed within the Adobe Reader software, you can do some very
lightweight GIS analysis. The GeoPDF format is relatively new; expect to see more functionality
in the near future. FYI, the free Terra...
View Full Document
- Fall '14