generate data for plot_spatial()
getSpatialPlotData(online = TRUE, date = "2017-01-01",
metric = "t_official")if TRUE(default),realtime data is pulled from the API. if FALSE, data is pulled from sample offline database
date for which spatial plot is needed. Default: 2017-01-01
metric for which spatial plot is needed. Default: "t_official"
a dataframe of values for the given metric and date