How to install a program in a ‘system location’?

I am quite new to Linux in general, using Ubuntu 16.04. I am planning to install the ecCodes software (https://software.ecmwf.int/wiki/display/ECC/ecCodes+installation), to load some grib files into R using the gribr package. The installation instruction of the gribr package suggest that the ecCodes library should be best installed into a system location (“ecCodes installed in a system location: The the libraries/headers should be found by the linker/compiler without any additional environmental settings.”)

In the installation instruction of ecCodes linked above, the corresponding line in the instructions says

cmake -DCMAKE_INSTALL_PREFIX=/path/to/where/you/install/eccodes ../eccodes-x.y.z-Source 

So, to what path do I need to set /path/to/where/you/install/eccodes so that this is an appropriate system location?