CIESE - International Boiling Point Project

Project Finished - Next Run Fall 2008

Help for Reading TopoZone Maps

Check out the TopoZone to view online USGS maps. These topographical maps will help you find the elevation of your school (or other location) as well as latitude and longitude.

From the TopoZone web site: "January 6, 2000 - Groton, MA. TopoZone today announced that it has been selected as the winner of the Second Annual "Best of the Net" Award by About.com and has been designated as the #1 Online Geography Site for 1999. TopoZone is the first interactive topographic map and database of the entire United States and is accessible at no charge to anyone with an industry standard Web browser."

General Instructions

Enter a Place Name in the search box on the first page or click on Get a Map at the top of the page and enter a Place Name. Enter in the name of your city or town. Do not enter your state name. The search results will display all the places with the name you typed. It will give latitude, longitude, and elevation data for each of those locations. However, you can find more precise information by viewing the map.

The scale of the displayed map is shown in the bars at the top left of the page. The default map will be at the scale of 1:100,000. The size of the map is shown at the top right of the page and the default size should be Small. The latitude and longitude of the map center (in decimal degrees) is also displayed at the top of the page. Clicking on the green arrows at the corners and in the middle of each side will let you see more of the map in that direction. Clicking anywhere in the map centers the map around that location.

Finding the Elevation of Your School

Click on the 1:25,000 scale button. After it redraws you can click on any point on the map to re-center it, then click on the Medium or Large size button. At this resolution, you can easily locate street corners and even buildings on your school site. The contour lines should also be visible. The contour line intervals will vary depending on the map you are viewing. Sometimes the contour lines are in 5 feet intervals and sometimes 20 feet (or other) intervals. Count how many lines are between the numbered contour lines to figure out this interval. For example, if you see a 200 foot contour line and a 300 foot contour line and there are 4 unmarked lines in between them, the contour lines will be: 200 ft (marked), 220 ft, 240 ft, 260 ft, 280 ft, and 300 ft (marked). Note: all measurements on USGS maps are in feet.

Try to find the nearest contour line to your school. If your site lies in between two contour lines, try to estimate what the elevation would be between those lines. Once you have determined the elevation of your location, use a conversion calculator (found on the Reference Material page) to convert your elevation into meters. Or, if you would prefer to do it by hand, 1 foot = 0.3048 meters.

Finding the Latitude and Longitude of Your School

As you move your cursor around the map the latitude and longitude coordinates are displayed in the browser status bar at the bottom of the screen. The coordinates will change as the cursor moves. The coordinates shown may not be for the exact location you are pointing at, but rather, the coordinates for that tile of the map. However, this still might be a better approximation than what you may find for the general latitude and longitude coordinates of your town.

** Special thanks to Dave Williams for providing these instructions **