Add table and functions to store and retrieve values for calibrating the total number of people and the total structural value
As described in https://git.gfz-potsdam.de/globaldynamicexposure/collaboration/-/issues/578, the population numbers as well as the total structural values per country are in general much higher than in the source models (with factors of up to 10). This requires a calibration to the values in the source models or to other data sources (e.g. Wikipedia).
Therefore, exposure-lib needs to provide a table to store the respective values to calibrate to. The table should comprise the following values:
- Country ISO code
- Total population number from the source model
- Calibration factor for population
- Total structural value from the source model
- Calibration factor for structural values
For the population, it might be more useful to use the population number provided by Wikipedia as they are usually more recent and better reflect the total population than the (older) source models can do.
I see two possible pathways for the implementation here:
- A dedicated table with the aforementioned fields and an index on the country ISO code
- A multi-purpose metadata table that stores data as key-value pairs. In this case, these pairs could look like: key:
JPN.Population.Wikipedia, value:125416877, or key:JPN.Population.Calibration, value:0.874
I think the latter option is the better one as we will be able to introduce further metadata without changing the database table definitions.