This function can get point data about any of the NPN geospatial layers.
npn_get_point_data(layer, lat, long, date, store_data = TRUE)The coverage id (machine name) of the layer for which to
retrieve. Applicable values can be found via the npn_get_layer_details()
function under the name column.
The latitude of the point.
The longitude of the point.
The date for which to get a value.
Boolean value. If set TRUE then the value retrieved will
be stored in a global variable named point_values for later use.
Returns a numeric value for any NPN geospatial data layer at the
specified lat/long/date. If no value can be retrieved, then -9999 is
returned.
Please note that this function pulls this from the NPN's WCS service so the
data may not be totally precise. If you need precise AGDD values try using
the npn_get_agdd_point_data() function.