MET has a collection of survey data provided by the Norwegian road administration. This data is primarily sampled from a selection of fjords in Sunnmøre in regards to the 'ferry-less' E39 road plan.
The data is stored in a common network common dataform (netCDF) format, which enables multidimensional variables. It is a widely used data format for scientific data. Every .nc file has a myriad of variables, all of which has descriptive meta-data.
Since it is difficult to publish multi-dimensional data through MQTT, some compromises have been made. For example, the measurement of salinity is stored and accessed with regards to both time and depth. I.e to get a value for salinity, depth and time must be provided. Time can be provided through timestamp, but depth has to be set to a static variable. In this case the depth is set to be always 5 meters.