How would you describe the difference between true position and a coordinate location?

How would you describe the difference between true position and a coordinate location?

• A. True position is the geometric relation to the datums with a defined tolerance.
• B. Coordinate location is the geometric relation to the datums with a defined tolerance.
• C. True position is a numerical value without reference to datums.
• D. Coordinate location is a numerical position without necessarily referencing a tolerance frame.

Answer: (A)

True position controls where a feature lies in relation to the datum reference frame, and it uses a specified tolerance zone to define how far the actual location can deviate from the ideal, true position. The datum frame sets the origin and orientation, so the true position is always described with respect to those datums, not in isolation. The tolerance zone is what makes the position meaningful as a GD&T requirement—for example, a cylindrical zone around the intended centerline of a hole that defines the allowable variation. Coordinate location, by contrast, is just giving a numerical position without necessarily tying it to datums or imposing a tolerance to govern allowable variation. It describes where something should be located in a coordinate system, but it doesn’t inherently specify how much deviation is permissible or how the location should be constrained relative to datums. So the best description emphasizes that true position is a datum-based relation with a defined tolerance, precisely what keeps the feature located within a controlled zone in the datum reference frame.

True position controls where a feature lies in relation to the datum reference frame, and it uses a specified tolerance zone to define how far the actual location can deviate from the ideal, true position. The datum frame sets the origin and orientation, so the true position is always described with respect to those datums, not in isolation. The tolerance zone is what makes the position meaningful as a GD&T requirement—for example, a cylindrical zone around the intended centerline of a hole that defines the allowable variation.

Coordinate location, by contrast, is just giving a numerical position without necessarily tying it to datums or imposing a tolerance to govern allowable variation. It describes where something should be located in a coordinate system, but it doesn’t inherently specify how much deviation is permissible or how the location should be constrained relative to datums.

So the best description emphasizes that true position is a datum-based relation with a defined tolerance, precisely what keeps the feature located within a controlled zone in the datum reference frame.