World Ocean Atlas

How to open data from World Ocean Atlas in R

 
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# OPEN data from World Atlas NOAA 
# http://www.nodc.noaa.gov/cgi-bin/OC5/WOA05/woa05.pl
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### Tim Bover from WOA09 (how to obtain the file from internet, and download to your computer):
#   - Go to http://www.nodc.noaa.gov/OC5/SELECT/woaselect/woaselect.html
#   - select the oceanographic variable you are interested in
#   - select geographic area (or leave whole world), type of data
#    (probably climatological mean in your case), time period and depth
#    (depth is not that important.  The data files contain all standard
#     depths available)
#   - click on 'Show Figure'
#   - on the resultant page, on the left, above the figure, you will see
#    'Data Access: ASCII ArcGIS'
#   - click on the ASCII link (or left mouse button and 'save target as').
# readLines(file.choose()) # Let the user choose the local file to read (thank's to Luke Miller)
# setwd("C:\\Users\\Marta Rufino\\world")
h(readLines("data\\WOA05\\temperature.gz")) #this may take some time...
 
# note the path indicates the folder wher you have the file. 
# You can get the path, by clicking the left mouse button and properties, 
# using windows explorer, for example or changing R working directory to the folder where you have your file
# Note also that the file name will be different from the current one (it is generated automatly by WOA)
# Whatever way you have to obtain the path, note that you need to change the bars: instead of \ put \\ or /
T=read.table("data\\wfig1323085620.23584.csv.gz",
     sep=",", col.names=c("lat","lon", 
     paste("t",c(0,10,20,30,50,75,100,125,150,200,250,300,400,500,600,700,800,900,1000,1100,1200,1300,1400,1500,1750,2000,2500,3000,3500,4000,4500,5000,5500), sep="")))
dim(T)# to check if everything is ok...
summary(T)
 
## If we want to work with the data as a spatial object:
require(sp)# this package is required for working on most spatial objects.
T.spa=T
coordinates(T.spa)=~lon+lat
gridded(T.spa)=TRUE
#proj4string(T.spa)=CRS("+proj=longlat +datum=WGS84") # if we wanted to define the projection... which is not exactly this one for all but 
summary(T.spa)
 
#image(T.spa, "t0") #for plotting temperature, at zero depth, for example. Note we can plot the 35 depth levels.
spplot(T.spa, c("t0","t10"), col.regions=rev(heat.colors(20)))
#spplot(T.spa, c("t0","t10"), col.regions=rev(rainbow(100)), at=seq(30,40,l=100),main="Temperature")
 

Created by Pretty R at inside-R.org


This map represents temperature at 0 and 10 m depth ;)