If you wanted to create an attribute recording the distance from each vehicle in a layer to the nearest gas station, which transformer could you use?

If you wanted to create an attribute recording the distance from each vehicle in a layer to the nearest gas station, which transformer could you use?

• A. Aggregator
• B. Clipper
• C. NeighborFinder
• D. PointOnAreaOverlayer

Answer: (C)

Measuring how far each vehicle is from the closest gas station requires a proximity lookup between two layers. NeighborFinder performs a nearest-neighbor search: for every input feature (the vehicles), it searches the reference features (gas stations) and outputs the distance to the closest gas station as a new attribute. It can also provide the identifier of that nearest gas station if needed. This directly gives you an attribute on each vehicle that records its distance to the nearest gas station. The other transformers don’t perform this cross-layer proximity calculation. Aggregator computes statistics over features, not per-feature distances to another layer. Clipper trims input features by clipping with polygons, and PointOnAreaOverlayer assigns points to polygons or areas without calculating distance.

Measuring how far each vehicle is from the closest gas station requires a proximity lookup between two layers. NeighborFinder performs a nearest-neighbor search: for every input feature (the vehicles), it searches the reference features (gas stations) and outputs the distance to the closest gas station as a new attribute. It can also provide the identifier of that nearest gas station if needed. This directly gives you an attribute on each vehicle that records its distance to the nearest gas station.

The other transformers don’t perform this cross-layer proximity calculation. Aggregator computes statistics over features, not per-feature distances to another layer. Clipper trims input features by clipping with polygons, and PointOnAreaOverlayer assigns points to polygons or areas without calculating distance.