# Comparing Mapping Sets

The content of two Mapping Sets can be compared and the user is able to inspect the differences in a table. Mapping Sets are compared in terms of *Base* and *Target* Mapping Sets in order to define additions, removals, and changes. To execute a Mapping Sets compare, navigate to `Tools > Compare Mapping Sets...` .

![Compare Mapping Sets main menu option](https://snowowl.atlassian.net/wiki/download/attachments/1333985647/01.png?version=2\&modificationDate=1605110727058\&cacheVersion=1\&api=v2)

The menu opens the **Compare Mapping Sets Wizard** where the *Base* and the *Target* Mapping Sets can be selected from a pick-list. Users can also select the necessary attributes to be considered in the comparison.

![Compare selection wizard](https://snowowl.atlassian.net/wiki/download/attachments/1333985647/02.png?version=2\&modificationDate=1605110760615\&cacheVersion=1\&api=v2)

{% hint style="success" %}
After the comparison process, a dedicated read-only editor opens with a table summarizing the results of the comparison. 
{% endhint %}

A *Summary* section at the top displays the overall statistic of the comparison, which can be collapsed. The summary part - as well as the **Explanation** **Column** below - determines the status of the given mapping according to the selected *Base* Mapping Set. 

{% hint style="info" %}
For example, if a mapping receives a *Missing* status, then it is missing from the *Base* Mapping Set and only the *Target* Mapping Set contains that particular mapping.
{% endhint %}

![Map Compare results](https://snowowl.atlassian.net/wiki/download/attachments/1333985647/image2020-12-10_14-39-9.png?version=1\&modificationDate=1607607547821\&cacheVersion=1\&api=v2)

Identical mappings can be filtered out by clicking on the ![](https://snowowl.atlassian.net/wiki/download/attachments/611027327/icon-02.png?version=1\&modificationDate=1604066510639\&cacheVersion=1\&api=v2) **`Hide identical mappings`** button in the top-right corner of the editor.

The editor toolbar also offers the ![](https://snowowl.atlassian.net/wiki/download/attachments/1333985647/mappingset-plus.png?version=1\&modificationDate=1606491735657\&cacheVersion=1\&api=v2) **`Generate new Concept Map from the Same members`** button, which enables users to generate a new Mapping Set from the Map Compare results. 

{% hint style="info" %}
The new Mapping Set will inherit only the matching (*Same*) members of the compared Mapping Sets, the rest of the mappings need to be cherry-picked by the user. 
{% endhint %}

The action reveals a wizard where the new Mapping Set properties can be specified. Optionally, users can also carry over comments to the generated Mapping Set by ticking the **`Copy comments`** checkbox.

![New Mapping Set wizard](https://snowowl.atlassian.net/wiki/download/attachments/1333985647/image2021-3-19_15-27-43.png?version=1\&modificationDate=1616164065002\&cacheVersion=1\&api=v2)

A third, ![](https://snowowl.atlassian.net/wiki/download/attachments/1333985647/image2020-12-10_14-20-30.png?version=1\&modificationDate=1607606428947\&cacheVersion=1\&api=v2) **`Export the compare results separated by semicolon to a text file`** button is also available in the editor, which enables users to export the necessary information from the Map Compare results. 

![Concept Map Compare Export Wizard ](https://snowowl.atlassian.net/wiki/download/attachments/1333985647/image2021-3-22_12-12-31.png?version=1\&modificationDate=1616411553336\&cacheVersion=1\&api=v2)

{% hint style="info" %}
A limit is included to reveal only a maximum of 50 000 items in the **Compare Editor**. If it is required to work with all the values, the result can be exported or users can find their mappings by using the filter search. Although there might be mappings that are not present in the editor, the  ![](https://snowowl.atlassian.net/wiki/download/attachments/1333985647/mappingset-plus.png?version=1\&modificationDate=1606491735657\&cacheVersion=1\&api=v2)**`Generate new Concept Map from the Same members`**toolbar menu option ensures that all items are included in the newly generated Mapping Set.
{% endhint %}


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