Which of the following is not a source that can be sampled by a sample line?

• A. A Surface
• B. A Corridor
• C. A Parcel
• D. A Feature Line

Answer: (C)

A sample line reads data from a 3D source along its length, pulling elevation and geometry information to create sample points or sections. Surfaces provide continuous elevation data across all X, Y positions, so they are a natural source for sampling. Corridors contribute design surface data and other elevation information along the corridor’s extent, making them another valid source. Feature lines are 3D polylines with assigned elevations, so they can also supply sample data along the line.

Parcels, however, are defined areas for ownership and boundaries and do not inherently carry elevation data along a line. They’re not a 3D surface or a line with elevations to sample from unless you first create a surface from them or otherwise derive 3D data. Because a sample line needs a 3D source to read elevations, a parcel is not a direct sampling source.