ws_metadata_by_date_2_pgdb: ws_metadata_by_date_2_pgdb() stores NOAA information into...

In rabravo/ws2pgdb: Retrieves, manipulates, and stores data from NOAA, U.S.Census, and Epimodels.org. Uses location of weather stations (ws) to create a clustering of counties around the ws

Description

This function uses the metadata returned from all_coor_ws which in turn uses the rnoaa API to retrieve NOAA data. Metadata includes the mindate, and maxdate dates. Given a particular variable (i.e. TMAX, TMIN, PRCP, etc), we are interested to retrieve the number of weather stations whose time window defined by the interval [mindate, maxdate] intersects and the length of the time window is maximum. Searching for answers online,the solution is a hard computing problem. It belongs to the set of problems defined as the 'Maximum Subset Intersection' problem which are close-related to the set cover problem studied in graph theory. The following function computes a resulting set using an heuristic described through the comments in the body of the function. It starts with the current year and the span variable defines the threshold for the algorithm to search for the answers.

Usage

ws_metadata_by_date_2_pgdb(geoid, type, stations, ssDate, ffDate)

Arguments

geoid	FIPS number from census tables (tiger files)
type	Variable under investigation i.e. TMAX, TMIN, PRCP
stations	The universe of stations from the rnoaa API from where the new subset will be computed.
ssDate	Staring date from interval to retrieve weather data
ffDate	Final date from interval to retrieve weather data

Value

Returns the name of the new table of the subset of weather stations with intersecting data

Note

Remember that all_coor_ws() returns a set of stations.

Examples

stations <- as.data.frame(all_coor_ws( ghcnd = 'GHCND', geoid = '48113', type = 'TMAX'))
ssDate <- '2000-01-01'
ffDate <- '2001-01-01'
ws_metadata_by_date_2_pgdb( geoid = '48113', type = 'TMAX', stations, ssDate, ffDate) 

rabravo/ws2pgdb documentation built on May 26, 2019, 8:51 p.m.