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The triangles in a triangulation system can be arranged in a number of ways: some of
the commonly used arrangements, also called layouts, are as follows:
Single Chain of triangles:

Double Chain of triangles:

Triangulation Net Adjustments
This involves adjustment of angles by equal amounts and the application of the side
equation. Provided all angles (or directions) have been observed to a high standard,
this form of adjustment may suffice for small figures. However, unless the figure is
exceptionally well conditioned, it will fail badly in a geodetic figure where spherical
excess (ε) is a factor. (Note 1 "ε for 2002 km).

Triangle condition
Sum of triangle = 180 as (1+6+7+8=180)
Local condition
Sum of angles around point = 360
As (1 +2 +9 = 360)
Side condition
The length of side calculating from any angles by any routes using sine's law must be
same

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