The other methods are surprisingly accurate, but with a little more math and specialized tools you can get a more accurate reading. It's not as daunting as it sounds: all you need is a calculator that can calculate tangents, and a cheap plastic protractor, straw, and piece of string so you can Make a Clinometer yourself. A clinometer measures the slope of objects, or in this case the angle between you and the top of the tree. A transit is a more complicated tool used for the same purpose, but uses a telescope or laser to achieve more accuracy. The Piece of Paper method actually uses a piece of paper as a clinometer. This method, besides being more accurate, allows you to measure the height from any distance, instead of moving forward and backward to get the paper to line up with the tree. Stand with your back to the tree and walk out to a point that is approximately level with the ground at the tree’s base and from which you can clearly see the tree’s top.  Walk in a straight line, and use a measuring tape to measure your distance from the tree.  You need not stand any set distance from the tree, but this method generally works best if your distance from the tree is about 1-1.5 times the height of the tree. Sight the top of the tree and use a clinometer or transit to measure the "angle of elevation" between the tree and the ground.  The angle of elevation is the angle formed between two lines—the flat plane of the ground and your sight line, to some elevated point (in this case, the tree’s top) — with you as the vertex of the angle. You can find the tangent of an angle using a calculator or table of trigonometric functions. The method for finding the tangent may differ depending on your calculator, but usually you just push the “TAN” button, enter the angle, and then press the  “equal” button (=).  Thus if the angle of elevation is 60 degrees, you simply push “TAN” and then enter “60” and then press the equal sign.   Click this link to go to an online tangent calculator. The tangent of an angle in a right triangle is defined by the side opposite the angle, divided by the side adjacent to the angle. In this case, the opposite side is the height of the tree, and the adjacent side is your distance from the tree. Remember, you measured your distance from the tree at the beginning of this method. Multiply it by the tangent you calculated. The resulting number tells you how high the tree is above your eye level, since that's the level you calculated the tangent from. If you read the earlier substep about the definition of the tangent, you can see why this method works. As described earlier, the tangent = (tree's height) / (distance to tree). Multiply each side of the equation by the (distance to tree) and you get (tangent) x (distance to tree) = (the tree's height)! Now you have the height of the tree. Since you used the clinometer or transit at eye level, not ground level, add your height to the measurement to get the total height of the tree. You can get a more accurate result by measuring your height at eye level, not to the top of your head. If you are using a stationary transit, add the height from the transit eyepiece to the ground, not your own height.
और ज्यादा सटीक मेजरमेंट पाने के लिए इस मेथड का यूज करें: नजर आने वाली किसी पोजीशन पर से दूरी को मापें: पेड़ के ऊपरी हिस्से पर एंगल ऑफ एलिवेशन (angle of elevation) निकालें: एंगल ऑफ एलिवेशन की टेंजेंट को निकालें: पेड़ से लेकर अपनी दूरी को, एंगल ऑफ एलिवेशन की टेंजेंट के साथ में मल्टीप्लाय कर दें: पहले के स्टेप में कैलकुलेट की हुई हाइट में, अपनी हाइट को एड कर दें: