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Projects > iPinPoint - Angle and length/distance measurement tool, v2.1
How to add points on a picture
It is important to mention that the accuracy of the calculations depends on the quality of the picture. For best results you need to take a picture of the object of interest from a short distance. Also, you need to point the camera straight at the object of interest and you should NOT take the picture from an angle. In other words, stand in front of the object. If that is a distant object, position yourself to the shortest possible distance from that object. If you made a mistake you can change the location of the points by dragging them or you can click on the "Redo" button to start over.

Magnitude of an angle

In order to measure the magnitude of an angle you need to pinpoint 3 points on the picture. Please note that a picture projects a 3-dimensional object into a 2-dimensional object, and hence, you can accurately measure the magnitude of angles which lie in a plane. Therefore, when you take a picture of a 3-D object make sure that you capture only one side of this object, and you can measure the magnitude of the angles on that side. In the case where the object does not have a uniform surface (i.e., the human face), you may need to take more than one pictures. For example, if you take a picture of a human being from the front, you can measure the magnitude of the angle that his/her hands make with the chest. If, instead, you take a picture of a running person from the side, you can measure the magnitude of the angle of his/her knee.

Measuring the length of an object

In order to measure the length of an object you need to pinpoint 4 points on the picture. The first two points are in blue color and the rest in red color. The length of an object is measured relative to the length of a yardstick. The yardstick can be any object! It could, for example, be a pencil or your credit card. It needs to be an object whose dimensions are known, however. Place the yardstick near the object of interest, and position the yardstick so that its larger side is aligned with the side of the object that you want to measure. Namely, if the yardstick is a pencil, and you need to measure the height of the object, place the pencil vertically next to the object. If, instead, you want to measure the length, place the pencil horizontally. Next, you pinpoint the two ends of the yardstick (blue color), and then you pinpoint the length of the object of interest. Once you have pinpointed 4 points, click on the "Calculate" button, give the length of the yardstick, and iPinPoint will calculate the length of the object of interest.

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