One of the two most commonly used programs I run on the Raspberry PI is OpenCPN an open source chart plotter software that is community sourced.
The joy of community sourcing is that there are lots of people contributing to the features of OpenCPN and so it has a healthy Plugin market that allows features to be added to the underlying software.
One of these features is support for Radar that is really quite good and the main reason we usually run OpenCPN as well as qtVLM.
The main reason we tend to use qtVLM instead of OpenCPN for everything else is also because of the open sourced nature of the product meaning the interface is more simplistic and less “designed” for use as well as some reliability issues arising out of the number of developers involved rather than a more singular approach of the likes of qtVLM.