Using a Projection Node
A Projection node is one of the most popular nodes and they usually appear in most calculation views of all types. They provide many useful features that most calculation views require.
![Screen capture of a calculation view of a Projection Node. It displays the Mapping tab with some mapped and some unmapped columns. Screen capture of a calculation view of a Projection Node. It displays the Mapping tab with some mapped and some unmapped columns.](/service/media/topic/e5b61bd9-7682-4826-addf-f61e2ad5d203/HC300_07_en-US_media/HC300_07_en-US_images/projection_node.png)
A Projection node is typically used to achieve the following:
To select only the required columns from a data source.
To define calculated columns.
To define parameters that request values at run-time, such as user-prompts.
To apply a filter on the data source.