Question: How are Obstruction Identification Surfaces to be drawn?

Answer: Per the Data Capture Rules in Section 5.5.4 defining the requirements for Obstruction Identification Surfaces, “depict the horizontal limits of the appropriate obstruction imaginary surface.”

This means you should depict the outside shape of the polygon. Place vertices intervals sufficient to adhere to the accuracy requirements for these features and ensure they carry a Z value as well.

As a polygon, close the polyline (continuous line made up one or more straight segments) that defines the outer edge. That is, the starting and ending vertex must coincide.

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