This is result of typing following command:

~/snap/bin/gpt -h Collocate

You can get information about any SNAP operator using this command

==================================================================

Usage:
  gpt Collocate [options] 

Description:
  Collocates two products based on their geo-codings.


Source Options:
  -Smaster=<file>    The source product which serves as master.
                     This is a mandatory source.
  -Sslave=<file>     The source product which serves as slave.
                     This is a mandatory source.

Parameter Options:
  -PmasterComponentPattern=<string>     The text pattern to be used when renaming master components.
                                        Default value is '${ORIGINAL_NAME}_M'.
  -PrenameMasterComponents=<boolean>    Whether or not components of the master product shall be renamed in the target product.
                                        Default value is 'true'.
  -PrenameSlaveComponents=<boolean>     Whether or not components of the slave product shall be renamed in the target product.
                                        Default value is 'true'.
  -PresamplingType=<resamplingType>     The method to be used when resampling the slave grid onto the master grid.
                                        Default value is 'NEAREST_NEIGHBOUR'.
  -PslaveComponentPattern=<string>      The text pattern to be used when renaming slave components.
                                        Default value is '${ORIGINAL_NAME}_S'.
  -PtargetProductType=<string>          The product type string for the target product (informal)
                                        Default value is 'COLLOCATED'.

Graph XML Format:
  <graph id="someGraphId">
    <version>1.0</version>
    <node id="someNodeId">
      <operator>Collocate</operator>
      <sources>
        <master>${master}</master>
        <slave>${slave}</slave>
      </sources>
      <parameters>
        <targetProductType>string</targetProductType>
        <renameMasterComponents>boolean</renameMasterComponents>
        <renameSlaveComponents>boolean</renameSlaveComponents>
        <masterComponentPattern>string</masterComponentPattern>
        <slaveComponentPattern>string</slaveComponentPattern>
        <resamplingType>resamplingType</resamplingType>
      </parameters>
    </node>
  </graph>