> For the complete documentation index, see [llms.txt](https://docs.b2ihealthcare.com/snow-owl-authoring-platform/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.b2ihealthcare.com/snow-owl-authoring-platform/reference-sets/reference-set-types/map-type-reference-sets/complex-map-type-reference-sets.md).

# Complex Map Type Reference Sets

Complex Maps are used for one-to-many or many-to-one mappings, where you can specify rules and advice for the map execution as well as the level of generalization or specialization. One-to-many mappings are displayed in the table in separate lines.

{% hint style="success" %}
SNOMED CT Concept to any other Code System mappings are allowed.
{% endhint %}

To create a new Complex Map type Reference Set, right-click on a Reference Set type grouper concept in the Reference Set view and select the ![](https://content.gitbook.com/content/N7ynFOLTw3W9Zow9AaAJ/blobs/QvdWDiZ1TuPKUG8l9AKE/sct_new_complex_map_type_refset_icon.png)*New complex map type reference set...* Context Menu option.

Members can be added the same way as to a Simple type Reference Set.

Mandatory properties to be specified in the New SNOMED CT Reference Set Member Wizard:

| Property                 | Description                                                                                   |
| ------------------------ | --------------------------------------------------------------------------------------------- |
| **Referenced component** | The SNOMED CT component that is mapped to the other terminology or Code System                |
| **Map target**           | The target code in the target terminology, classification, or Code System                     |
| **Map group**            | A value grouping a set of Complex Map records from which one may be selected as a target code |
| **Map priority**         | The order in which Complex Map records should be checked within a map group                   |
| **Correlation**          | The correlation between the SNOMED CT component and the target code                           |
| **Module**               | The SNOMED CT module that contains this Reference Set member (primary module by default)      |

Other properties of Complex Map members:

| Property       | Description                                                                                                                                                     |
| -------------- | --------------------------------------------------------------------------------------------------------------------------------------------------------------- |
| **Map rule**   | A machine-readable rule, (evaluating to either `true` or `false` at run-time) that indicates whether this map record should be selected within its Map Group    |
| **Map advice** | Human-readable advice, that may be used to give an end-user advice on selection of the appropriate target code from the alternatives presented within the group |

Some of the properties can be modified afterward from the Complex Map type Reference Set Editor. In-cell editing is allowed in the specified member fields such as *groupNumber, mapPriority, mapAdvice, mapRule, correlation, mapCategory* columns when authoring Complex Map Type Reference Sets.