Build Your Own Surveying Tools
To do some basic surveying, you will need two important tools for measuring angles in their native habitat: a clinometer and a theodolite.
A clinometer (sometimes called an "inclinometer") is a tool for measuring vertical angles (angle of elevation). There are various ways to accomplish this but a simple example can be found here. Notice that the protractor under the sighting tube runs from -90° to 90°, with 0° in the center. When the user looks at an object through the tube, the weight will pull the string to point at the angle of elevation as marked on the protractor. It is important that the string's anchor point be the exact center of the protractor's (semi)circle.
A theodolite (sometimes called a "transit") is a tool for measuring horizontal angles, and, in its simplest form, consists of a full-circle protractor base with a swivelling sighting tube mounted at the center. This image might give you a better idea (you can ignore the vertical circle). To measure the horizontal angle between two objects, set the sighting tube to 0° and rotate the entire theodolite so that the first object is visible through the sighting tube. Then, holding the base steady, rotate just the sighting tube until the second object is visible. The sighting tube's position should now indicate the horizontal angle of separation between the two lines of sight.
Of course, to make these, you'll need some cardboard (cut up a box or find some sturdy paper plates), tubes (thin paper towel rolls or thick drinking straws work well), and suitable protractors. You could use a metal or plastic protractor, but it's probably cheaper to print one out. Here are some sites where you can find printable protractors:
Full circle protractor from Thingiverse. Could be useful for theodolite. It's monodirectional, though, so be prepared to either measure only counterclockwise or subtract your measurements from 360°.
Half circle protractor from ThinkZone. It's bidirectional and could be very useful for the clinometer, although you may want to cut it in half (at the 90° mark) and put the two halves back together with the 0°/180° marks touching so 90° is in the middle.
Polar coordinate graph paper from Incompetech (which also has all sorts of other graph paper generators). We'll be using polar coordinates later, but for now it'll make a serviceable protractor. A big advantage here is that you can use the "Reverse Labels" checkbox to get clockwise and counterclockwise protractors. Use the settings listed below, and experiment with the other settings until it looks the way you want it:
- Concentric Circles: 3
- Primary Spokes: 36
- Primary Labels: degrees
- Secondary Spokes: 360
If you find another useful printable protractor, or have the digital artistic skills to design a better one, let me know and I'll put it up on this site.
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