Syntax

   FACTORY_DEF <ReaderKeyword> SamplingFactory
   [FACTORY_NAME <factory name>]
   [INPUT FEATURE_TYPE <feature type>
      [<attribute name> <attribute value>]*
      [<feature function>]*]*
   SAMPLE_RATE <sample rate>
   [OUTPUT (SAMPLED|NOT_SAMPLED)
      FEATURE_TYPE <feature type>
      [<attribute name> <attribute value>]*
      [<feature function>]*]*

Overview

   This factory samples the input features at a specified rate and divides them 
   into two groups: those which are matched by the sampling rate, and those 
   which come between the sampled features. The first input feature and each 
   <sample rate> feature thereafter is considered a "sampled" feature. 

   However, when the sample rate is negative, then the sampling factory behaves 
   differently. For example, if the sample rate is -1, then only the first 
   feature will pass as sampled. Similarly, if sample rate is -2, then only the 
   first two featurers will pass as sampled, and so on.

   The SamplingFactory is useful to test mapping files being developed for large 
   data sources as it can greatly reduce the number of features processed by the 
   system.

      A sample rate of 1 passes all features through the factory. This can be 
      used to apply a feature function to every translated feature.

      A sample rate of 0 tells the SamplingFactory to treat all features as 
      unsampled features.

      A sample rate of -1 tells the SamplingFactory to pass only the first 
      feature as sampled feature.

      Note: Older versions of this factory did not support any output clauses, 
      and simply wrote out the sampled features. To maintain backward 
      compatability, an instance of the SamplingFactory which has no OUTPUT 
      clause will behave as if a clause of "OUTPUT SAMPLED FEATURE_TYPE *" has 
      been specified. This is non-standard FME behavior.

Output Tags

   The SamplingFactory supports the following output tags.
   
   SAMPLED  
   
      Features that occur at the specified <sample rate> are output with this 
      tag.

   NOT_SAMPLED 
   
      Features that come between the sampled features are output with this tag.