When the Summary Attribute input port is used, the Merge Features operator does not output any geometry. The Features Output operator fails with an error: "Input Features have no geometry".
If the input features have geometry and if the geometry output is desired in the output features, then a summary attribute defining the output geometry must be provided. Attributes have data types (for example: number, text, date, etc.) and some attributes are of the data type “area”, “line”, “point”, etc. Through the eyes of the Merge Features and Generate Functional Attributes operators, geometry is simply another attribute of a particular type.
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