| 摘要 |
An industrial survey marker for planimetric and altimetric goniometry has a vertical transparent cylinder with two conical cavities joined by a vertical cylindrical bore, a cylindrical base with a cylindrical shaft fixable in a triangular support, a conical cap with an axial transparent small cylinder, a conical point to the small cylinder outside the cap, a spherical surface forming a convergent lens at the lower end of the small cylinder and an internal light. The marker is pref. of plexiglass (methyl methacrylate resin). |
