Use a GPS (Global Positioning System) device to determine your altitude. GPS devices retrieve information from satellites. 'Altimeter' is a feature in your GPS device that gives extremely precise information about the altitude (accuracy up to 100 meters). Power on your GPS, and select 'Altimeter' from the main options list that is displayed when you power on your device. Some GPS devices may directly display the option 'Altitude' in the main options list.
Use a map to determine the altitude. Look for some prominent features in your surroundings and try to spot them on the map. You can look for a hilltop, a small valley between the hills or any other feature. Now, plot the same features on the map and estimate your position from those features. This will help you pinpoint your own location on the map. Now, count the total number of contours to your current position. Contours give the position of a given spot on the map from sea level. Your map will indicate the height of one contour. Multiply this value by the total number of contours to get your altitude.
Observe the vegetation around you. Typically, as you climb uphill, vegetation changes from leaf bearing trees to pines, bushes and moss, and finally to rocks and snow. If you get information about the altitude at which each of these changes becomes visible in the area you're currently positioned, you will be able to figure out your location. This is not a very accurate method, though.
Study the temperature changes. An increase in altitude is also characterized by drop in temperature. The local weather forecasts will probably cover the temperature levels at different altitudes. Measure the temperature of your surroundings and then use it to estimate your altitude. This method is also not very accurate.
