Variable input bug in kriging_analysis #288
Description
The expected treatment of the variable argument within Survey.kriging_analysis is to map inputs like "biomass" to "biomass_density". However, this does not work. Instead, the code incorrectly assumes that the biomass values are actually density values, which may result with outrageously large numbers. However, variable="biomass_density" works as intended. This is somewhat related to #286 insofar as ensuring that the validator correctly checks for this value type and assigns the corresponding column name when kriging the estimates.