Code to extract GODAS oceanography data from database, given that connection "channel" is defined.

getGODAS.r

#Function to extract GODAS oceanography data
#from SPC databases (adapted from Simon Hoyle)
#Gets the value from the nearest lon/lat grid cell
#lat resolution is 1/3 of a degree, lon is 1 degree
#Started: <2013-03-14 15:29:57 Laura>
#Time-stamp: <2013-03-15 14:37:55 Laura>



getGODAS <- function(tb,variable,year,month,rlat,rlon) {

if(any(c(length(rlat),length(rlon))!=2)) {
stop("Provide range for lat/lon coordinates as so: c(minlat,maxlat)") }

if(!exists("channel")) stop("Define object channel (connection to database)")

  variable <- paste(unique(variable),collapse=", ")
  year <- paste(unique(year),collapse=", ")
  month <- paste(unique(month),collapse=", ")

  query <- sprintf("select yy, mm, lat, lon, %s from %s where yy in (%s)
                   and mm in (%s)
                   and lon between %s and %s and lat between %s and %s",
                   variable,tb,year,month,
                   rlon[1]-1,rlon[2]+1,rlat[1]-1,rlat[2]+1)

  res <- sqlQuery(channel, query)
  }

# [Not used anymore]
# These functions assign coordinates to the appropriate 
# GODAS cell lat/lon (works for lat if centered on 0.5)

prep.lat <- function(x) {
    latv <- round(seq(-45.5,45.5,by=(1/3)),2)
    latv[cut(x,latv,labels=FALSE)] }

prep.lon <- function(x) {
    lonv <- round(seq(100.5,280.5,by=1),2)
    lonv[cut(x,lonv,labels=FALSE)] }