Math and Stuff

Some common math used in surveys:

To reverse compass headings, usually used when surveying out and you want to enter the data going into the cave.

        If bearing is between O and 179 degrees:

                        Bearing In = Bearing out +180

        If bearing is between 180 and 359 degrees:

                        Bearing In = Bearing out -180

If you take bearings using a bezel compass, but fix the bezel and take the reading directly off the compass, it will reverse right and left on your survey. T0 explain a little more, normally a bearing of 90 degrees is east or right if your facing north, if you fix the bezel and face east, your reading from the compass (without rotating the bezel) will be 270 degrees, which is normally due west or to the left when you face north.  To correct this, use this formula:

                            New bearing = 360 - old bearing

If you also need to reverse the heading, you can use the previous formula on the corrected bearings.