Depends on what you're trying to achieve, there are several possibilities

• Scaler
• Affiner
• AffineWarper (if you have known before-after reference points)
• Bufferer (with a negative buffer value)

For using the Scaler on rectangular polygons, you could try starting off by setting Scale Origin = Center Point, then use fractional scale factors, e.g. 0.5 for half the size.

i want to make the polygon small size but the polygon is not rectangular ,it is shape for a city with different curves ,i tried to do scale origin center point with factor 0.5 but it is still big .

i put for x = 0.5 and y =0.5 ,am i correct or what should i do ?

about affiner it has different coefficients from A to F . and i have coordinates x min and x max and y min and y max .which values should i use for a till f

about bufferer i have used with negative value but i found the shape changes different ,i want to make the polygon smaller but has the same shape but smaller .

Could you help me ? which transformer will help me and how to use correctly ?

Thanks for help

FME 2018

Scaler: If the resulting polygon is too big at a factor of 0.5, then you'll simply have to try smaller values.

Affiner: The parameters are explained in the documentation, see https://docs.safe.com/fme/html/FME_Desktop_Documentation/FME_Transformers/Transformers/affiner.htm

Unfortunately it's not possible to have an opinion on which transformer and settings is the best in your case, as we do not have enough information on your data, requirements, etc.