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In Metview 4, the default behaviour is to always overlay fields from different sources, even if their meta-data, such as date/time, do not match. This is different from Metview 3. The Overlay icon allows the configuration of this behaviour, whose default behaviour was to only overlay data whose timestamps 'match'. In Metview 3, there was a separate icon, the Overlay Control icon, which could be dropped into a View icon to change the overlay settings. In Metview 4 this is simpler, with a Map Overlay Control parameter directly in the Geographical View icon.
Cross Section Data, Average Data, Hovmoeller Data
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