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Reference mark

All dimensions used to construct the sundial are referenced from four survey marks

These marks can be temporary or installed as permanent

Permanent survey mark installed on concrete

  1. Tape paper onto concrete.

  2. Draw an ‘X’ onto the paper.

  3. Tape over the ‘X’ to prevent tearing of paper.

  4. Drill through paper with a 4mm or 3/16″ masonry drill bit.

  5. Hammer into the concrete a 12 gauge x 10mm or 1/2″ long stainless steel wood screw.


Temporary survey mark installed on concrete

  1. Temporarily glue wood block onto concrete or bitumen surface with acrylic gap fill such as No More Gaps. When this ‘glue’ is allowed to dry it will hold the wood firmly and will break off for easy cleanup.

  2. Mark an ‘X’ onto the wood

  3. Screw into the wood block


Temporary survey mark installed on grass

  1. Temporarily fasten wood block onto grass with tent pegs. The temp pegs are joined together with rope for hi visibility.

  2. Mark an ‘X’ onto the wood.

  3. Screw into the wood block.


Installing the four survey marks is also a measurement exercise. NS1 and NS2 are simply a measured distance on the north/south line. FP3 and FP4 are measured from NS1 and NS2 through geometry. This can be done quickly.

Finding the North/South line is time consuming. In the grass sundial above, the NS line is marked permanently by stretching a rope between a goal post and a permanently installed survey peg that is not on a playing area.


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