Create from point / impute from point functions

[janowicz]

Function to add/impute values in the disaggregate data (e.g. buildings, establishments) from spatial points representing observed values, such as from commercial data sources (e.g. InfoUSA, Metrostudy, Costar, Exceligent, REIS, Axiometric, Real Facts, D&B).

Examples of create from point:

create_from_point(buildings, commercial_data_source, how='replace')
create_from_point(buildings, commercial_data_source, how='add')

Examples of impute from point:

impute_from_point(buildings, commercial_data_source, {'unit_price':'price', 'non_residential_sqft':'sqft'})
impute_from_point(buildings, commercial_data_source, criteria='unit_price