There are many situations when you have two health systems that use incompatible versions of HL7. In these situations, Chameleon can be used to transform one version of HL7 into another.

Chameleon supports two different transformation algorithms: scripted transformation and graphical transformation.

• Scripted transformation (recommended option) - This transformation algorithm is based almost completely on Python scripting and is a more flexible option than graphical transformation (see Advantages Over Graphical Transformation). This is a good solution for HL7 mapping, since you only need to write code to change the fields and/or segments that are different between the two flavors, which results in very fast transformation capability. If you are building a new application, or you are new to Iguana, this method should be used, as it is the best long-term solution.

	For information on how to use Python to write transformation scripts in Chameleon, see Using Python Scripting. If you are new to Python, Learning Python provides an introduction to its principal features and constructs. When writing transformation scripts in Python, you can use the segment iterator object to access each of the segments and fields of an HL7 message in turn.

• Graphical transformation - This legacy algorithm is built on top of Chameleon's table architecture. The basic idea is to have two configurations, which are used to represent the input and output engines of the interface. Each configuration has the same table grammar in common, making it possible to map between the two configurations. Although this method can be used to perform message transformation, scripted transformation is the recommended solution, mainly due to its flexibility. Since this technique is considered a legacy method, any new applications built with Chameleon should not be using this technique. However, for backward compatibility purposes, this method is still supported.

	Message transformation techniques are implemented as follows: Chameleon - Via the transformMessage function call on the engine object. For more information, see the Language API Documentation for your language. Iguana - Via the message filter components (for more information, see To Message Filter and From Message Filter). To learn how to implement message transformation functions in Iguana, see HL7 Transformation.