This video provides a short introduction to mapping sets and their differences from SNOMED CT map type reference sets. You will then learn how mappings are organized in the mappings view and displayed in the editor. Finally, different search options for mapping sets and their members will be demonstrated.

This is the first video of a three-part series about mapping sets. You can find the other videos of this series at

You might also be interested in our other videos about mapping:

Once you’ve seen the video, you can find additional documentation at:




This is the first video of a series about working with mapping sets.

In Snow Owl maps can be created as a “Map type reference set,” which you would find here in the reference sets view or as a mapping set, which are organized in this view.

When you are defining a map, you’re linking components from one terminology as the source to components with similar meaning from another terminology, which would be called the map target. Both types – map type reference sets and mapping sets – are representing cross-links between terminologies, which option you choose depends on your requirements.

Map type reference sets are a SNOMED CT standard mapping SNOMED as the source to a specified target terminology. There are “simple maps” like this one here that represent one-to-one relationships. So here we would have a SNOMED CT concept mapped to an ATC code.

There are also “complex maps” like this one that also allow mapping from one SNOMED CT concept to multiple codes. Let’s see if I can find an example in this map here. Here’s one, you can see it’s the same SNOMED CT code, which is mapped to two different map targets in ICD-10. It’s also possible to define map groups and map rules in complex maps. As a SNOMED CT standard, map type reference sets can be exported in a specific format, which is RF1 or RF2, but also as a text file with specific delimiter characters like tabs or commas, that then can be used in Excel.

Mapping sets are not constricted to SNOMED CT. This means they can be used to create cross-links between two non-SNOMED CT terminologies like this example here, which is a map between local codes and LOINC codes. Mapping sets also allow associating components from different terminologies. In this example we can see SNOMED CT concepts that are mapped to different target schemes for example, ATC, ICD-10, LOINC and a local code system all in one mapping set, which would not be possible in a map type reference set where you are restricted to the target terminology that you specified. Mapping sets can be exported as Excel files but not in RF1 or RF2 format.

When you’re working with mapping sets it’s useful to use this perspective here, which is the mapping set perspective. We also use this icon to identify mapping sets, you can see this globe here, these are all mapping sets. This is the icon for complex map type reference sets and this is the one for simple maps, so you can see what kind of map it is.

Mapping sets can be opened from the view by simply double-clicking and this brings up the editor. We’ll talk about this in a second. Just a few words about the view itself. You can see these are the mapping sets and here I created some folders. This is optional but it makes sense if you have a lot of mapping sets to organize them in folders. It’s quite simple, you just click on this button and let me create a “Sample folder”, I click “Finish” and here is the new folder. Then you could either create a mapping set by right-clicking and selecting “Add mapping set” or if you already have a mapping set you just take it and simply drag it into the folder.

This view can also be linked to the editor. You already saw that it moved. So this means that if I activate an editor, I can also see where it would be in the view here, so you could see where it’s located, in which folder. These folders can be collapsed with this button, or expanded or you can individually open them by clicking the triangles.

It’s also possible to filter, for example, for a mapping set. If you’re looking for a mapping set, this also works for the name of the folders. You can create subfolders by right-clicking on a folder and selecting “Add new folder”. This is also where you would rename a folder or remove a folder. To delete a mapping set, that’s also here, just right-click it and then you could delete it or you could bookmark it, which would then show up in the Bookmarks view so if you have a mapping set that you use quite often you might want to bookmark it and then bring it up here from the Bookmarks view. So much about the view.

Now let’s take a closer look at the editor. I’m just going to double-click the tab to maximize it. The information on the left side is related to the source: We can see the name of source, which is in this case a local code system, the code ID and the term. On the right side is information about the target, which is SNOMED CT. The concept ID and the preferred term are displayed here. If you’re curious about one of the concepts, you can just double-click it and this will open the editor with additional information. This also works for the source terms: I can click this one and open the editor for the local code.

It’s also possible to customize this editor: You can resize this, you can also move columns or display additional information just by right-clicking on the top and bringing up the Table Preferences. We disabled most of this information so we just have the most basic information as a default, but you might want to display the status or the effective time or map groups and map rules can be displayed as well. Let me just click OK. If you change these, you need to close the editor and then bring it up again. Now we can see that all of these mappings are active. There’s a button here that displays inactive mappings, so there are two inactive mappings in this mapping set.

The properties of a mapping set are displayed on this tab: the name, definition, purpose, the version. It can be inactivated here and there are some additional fields for comments or the source that can be entered. Information can also be modified right here in this editor, only the version cannot be modified here.

When you’re searching for a mapping set, you can either use the filter as I already showed or you could also use the comprehensive quick search across all resources.

Let’s look for “ICD-9”. We can see that there are different SNOMED CT concepts, there’s a reference set, there’s a LOINC code and here is also a mapping set. To open this, I just select and click it. This brings up the editor. This is a pretty big mapping set with over 6,000 mappings and if you have a mapping set this size, it makes sense to use the filter. Let’s look, for example for “fracture”: There are 306 findings and you see all of these have the term “fracture” in it. If you want to clear the filter just click this X. Since we changed table preferences I can also see which ones are active or inactive.

If you’re looking for a particular member, you should use another way of searching, which is the advanced search here. I customized this, so that it just shows the Mapping sets search. There are different criteria, you can search for name, purpose, version, status, you can also combine certain criteria and the last two here are from members. Let’s look for a member that has the term “food” and we could further narrow this search by looking either just for the source or for the target or for both. The results are down here in the Search view. You can’t see the individual mappings only the mapping sets that contain mappings with the search term. The first one is this that we already have up, so let’s look for “food” – and there are 10 matches of source terms that contain the word “food”. The other mapping set would be “Occupations” and here we have just one, which is the “Food and beverages services manager.” You could also combine two search terms by using an operator. I could look for “food AND services”. You see now only this one mapping set came up because in the other one we don’t have a term that has “food” and “services” at the same time.

OK, that’s all I wanted to show about mapping sets for today. I hope you enjoyed it and in the next video we will create a mapping set and map terms. Thanks for your attention. Bye-bye.