Using the 2D / 3DPointReplacer, we can create a point from (x, y) / (x, y, z).
To create a line, I usually use the 2D / 3DPointAdder or the PointConnector after creating points.
If the created line is closed, these transformers generate a polygon.
If not (and if I need to create a polygon), also use the LineCloser.
Note: In FME 2014, the 2D/3DPointReplacer and the 2D/3DPointAdder have been integrated into the VertexCreator transformer.
2015-05-11: If you are going to create points based on coordinates (x, y) / (x, y, z) given by a CSV file or an Excel spreadsheet, you can also create them with the reader.
Look at the parameters dialog when adding the reader. If you set "x_coordinate", "y_coordinate" (and "z_coordinate") to the attribute types, the reader will create points based on the values.