Add check for existing data when retrieving basin data (like check for margin data)
Currently, missing data in site-data/basin/*.csv
files (i.e. a site is inside the polygon but not in the *.csv file) throws an error. Apply the same check used for the site-data/margin/*
data to handle sparse data. The new Bay Area basin data causes this error, as some grid points within the polygon do not have data. This may or may not be a temporary workaround, as it's not clear yet that the Bay Area data should have missing data.