You can simply click the outputport of the Reprojector and choose “Connect Inspector”.

Or, when using FeatureCaching, simply click on the magnifying glass.

I tried but if I look at two datasets together on the map they don’t show up in the same place when they should be. And I just found out that the old projection is set up on the map, so it still shows the previous projection? 

Sorry I’m new to FME still. 

How I think this works:

• If a background map is configured, the background map defines the projection.
• If no background map is configured, the first dataset in the inspector defines the projection.

So I suspect one of the sets entering the inspector has a different projection defined than you think. You can see this easily when you select a feature and look in the Feature Information window.

Personally, I work with multiple screens, and I display my data on a different screen than workbench, in the Data Inspector, not the Visual Preview. This is less cramped together in one window with workbench. You can set this under Tools → FME Options → tab Workbench, checkbox Data Inspection, Inspect with Data Inspector when Visual Preview window closed.

Thanks! I tried adding another layer with a different projection (EPSG:2154) from my data (it was EPSG:4326, I reprojected in EPSG:2154) and I can choose at the bottom which projection I want to look at the data (see photo). 

So I think even if I reproject my data with the transformer, it still shows with the original projection at first (the orginal projection is written in the Feature Information window), but I can choose which one I want when viewing in the map. I guess I need to really write the data after reprojection to really “encode” the new projection. 

Thanks for the tip about the Data Inspector, this will be helpful!