| 摘要 |
The present invention deals with an arrangement for making an estimate of the ground surface of a forest stand, which arrangement comprises a ruler 2, a first angle piece 3 fixed in the region of one end of the ruler, and a cursor 5 which can move along the ruler 2, on which a second angle piece 6 is fixed. The invention is characterised in that there is arranged on the cursor 6 at least one constant-size slit opening 8, which has a working position such that a sighting line from a point in connection with one of the ends of the ruler 2 extends through the slit opening 8 along the ruler 2. <IMAGE> |
