PowerBI

Ok, I think I understand what you're going for.

See attached an example PBIX below. What I've basically done is:

-1- Split out your A/B, C/E etc. Techs into new rows in Power Query.

-2- Also in Power Query, created a new dimTech table, that just contains a unique list of all the Tech Codes (A, B, C etc).

-3- Related the new dim table to both Machines and Technicians tables.

-4- Created the following measures:

_noofMachines = DISTINCTCOUNT(machine[Serial Number])

_noofTechnicians = DISTINCTCOUNT(technician[NAME])

_machineToTechRatio = DIVIDE([_noofMachines], [_noofTechnicians], 0)

_techToMachineRatio = DIVIDE([_noofTechnicians], [_noofMachines], 0)

-5- Using dimTech[techCode] in the visual, it gives the following output based on your example data provided:

In terms of getting this working on a map visual, you'll need to create dimension tables for Country/City/Zip etc. and relate to both tables in the same way as dimTech. It might be cleaner if you just create a location code in each of the fact tables, then your dimLocation table can have [locationCode], [Country], [City] etc. to be plotted on the visual.

Pete