Electronic marker with integral level indicator

An electronic marker comprising:

• a flat marker body defining a plane;
• an interrogatable electronic circuit located in said marker body, said interrogatable electronic circuit being responsive to an activation signal to send a marker identifier signal;
• and
• a visual level indicator integrally formed with said marker body providing a visual indication of when the plane of said marker body is horizontal.

An electronic marker with built-in leveling comprising:

• a circular, generally flat marker body defining a plane;
• a passive resonator circuit having a wire coil whose axis is normal to the plane and being responsive to a wireless activation signal to send a wireless marker identifier signal, wherein the wire coil is embedded within said marker body proximate a periphery thereof;
• and
• an air-bubble level integrally formed from a circular semispherical portion of said marker body, said semispherical portion forming a chamber which is partially filled with a liquid leaving an air bubble, and having a printed circle, wherein said circle, said semispherical portion and said marker body are all concentric such that the air bubble being within the circle provides a visual indication of when the plane of said marker body is horizontal.