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Integrating two or more data layers into one layer
Intersect (implemented)
Results of this operation include all parts that occurs in all input layers
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Field: all fields from all input FeatureDatasets are merged into the result FeatureDataset
Union (not implemented)
Results of this operation include all parts that occurs in any input layer
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Field: all fields from all input FeatureDatasets are merged into the result FeatureDataset
Generalization
Dissolve
Aggregates features based on specified attributes
Input: one FeatureDataset, fields that user specified
Output: one FeatureDataset
Type: simple iterations 
Feature: many features which have same value(s) in certain field(s) will be merged into one feature
Field: "id" field, the user-specified field(s) (additionally, fields with statistical results)