You use PointOnAreaOverlayer to create a list containing data, including capacity, for all the music venues (points) in each neighborhood (areas) of a city. What transformer would you let you add up the total audience capacity of each neighborhood?

You use PointOnAreaOverlayer to create a list containing data, including capacity, for all the music venues (points) in each neighborhood (areas) of a city. What transformer would you let you add up the total audience capacity of each neighborhood?

• A. ListHistogrammer
• B. ListRangeExtractor
• C. ListSummer
• D. ListAverager

Answer: (C)

Summing values from a list to produce a single total is exactly what this scenario requires. After using PointOnAreaOverlayer, you have a list of venue capacities for each neighborhood. To obtain the total audience capacity for each neighborhood, you need to reduce that list to one number—the sum. ListSummer performs that reduction by taking a numeric list and outputting the sum as a new attribute. This directly gives you the total capacity per neighborhood. The other transformers don’t fit because they perform different reductions: ListHistogrammer creates a histogram from the list, not a total; ListRangeExtractor pulls out the min and max values from the list; ListAverager would compute the average capacity per venue, not the total.

Summing values from a list to produce a single total is exactly what this scenario requires. After using PointOnAreaOverlayer, you have a list of venue capacities for each neighborhood. To obtain the total audience capacity for each neighborhood, you need to reduce that list to one number—the sum. ListSummer performs that reduction by taking a numeric list and outputting the sum as a new attribute. This directly gives you the total capacity per neighborhood.

The other transformers don’t fit because they perform different reductions: ListHistogrammer creates a histogram from the list, not a total; ListRangeExtractor pulls out the min and max values from the list; ListAverager would compute the average capacity per venue, not the total.