| PRACTICAL 3: STEREOGRAPHIC PROJECTION AND THE STEREONET. |  |
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| How to determine the pitch of a line along a plane, and how to determine the angle between planes and lines?
The pitch of a line lying on a plane is the angle between this line and an horizontal line on the plane. The angle is measured along the plane. In this exercise after plotting a line on a plane using its pitch, we determine the angle between the pole of the plane and this line. The construction proceeds that way... |
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| First, plot the plane (here in green) that carries the line and also its pole (blue crossed dot). | With the plane aligned in the NS direction count 38º along the plane from the approriate pole (here the South pole) and mark a dot. The appropriate pole is the one that will give you the pitch directed toward the South after you rotate back the overlay. | Rotate the overlay back to its fundamental position. To measure the angle between this line and the pole of the plane, rotate the overlay so that the two dots align along the same great circle. The angle is measured along that great circle counting from one dot to the other. | ||||||||||
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