Surveyors Compass

Graduation disc is fixed in this type of compass to the box and magnetic needle is free to rotate above it. At viewing end there is no prism provided, but there has a narrow slit. The reading is directly taken from the top of the glass cover after fixing the line of sight. Therefore, graduations are directly written (not inverted). Graduations are from zero to 90°, zero being to north or south and 90° being to east and west in this compass. An angle of 20° to north direction to the east is written as N 20° E, and an angle of 40° to east from south is written as S 40° E. Always first direction show is south or north and the last letter shows east or west direction. Graduated circle rotates with line of sight and magnetic needle is always towards north in this system. The reading is taken at the tip of needle. Therefore, on the compass east and west are marked interchanged and marked. Above describe plate indicate the photograph of a surveyors compass.

 Plate Surveyor's compass