Changes between Version 19 and Version 20 of udg/ecoms/RPackage/examples

Timestamp:

May 20, 2013 11:34:21 AM (9 years ago)

Author:

juaco

Comment:

--

udg/ecoms/RPackage/examples

@@ -383 +383 @@
 
 
+This is how we can check the spatial domain of the dataset:
+
+{{{
+> lats = inv.iberiaNCEP$SLPd$Dimensions$lat$Values
+> lons = inv.iberiaNCEP$SLPd$Dimensions$lon$Values
+> plot(expand.grid(lons,lats), asp=1)
+# 'world' from library 'fields'
+> world(add=TRUE)
+
+}}}
+
+[[Image(iberiaNCEPextent.png)]]
+
 = loadData =
 
-
-
+Once the NcML dataset is created and we get an idea of the nature of the variables stored, the `loadData` function is used to retrieve the variables desired at selected dimensional slices. In this particular example, we will load the temperature data from the NCEP reanalysis in the Iberian Peninsula.
+
+We have a look again to the description of the variable temperature, as provided by the `dataInventory`: 
+
+{{{
+> str(inv.iberiaNCEP$T)
+List of 5
+ $ Description: chr "Temperature"
+ $ DataType   : chr "float"
+ $ Units      : chr "K"
+ $ TimeStep   :Class 'difftime'  atomic [1:1] 24
+  .. ..- attr(*, "tzone")= chr ""
+  .. ..- attr(*, "units")= chr "hours"
+ $ Dimensions :List of 4
+  ..$ level:List of 3
+  .. ..$ Type  : chr "Pressure"
+  .. ..$ Units : chr "millibar"
+  .. ..$ Values: num 850
+  ..$ time :List of 3
+  .. ..$ Type  : chr "Time"
+  .. ..$ Units : chr "days since 1950-01-01 00:00:00"
+  .. ..$ Values: POSIXlt[1:16071], format: "1958-01-01" "1958-01-02" "1958-01-03" "1958-01-04" ...
+  ..$ lat  :List of 3
+  .. ..$ Type  : chr "Lat"
+  .. ..$ Units : chr "degrees north"
+  .. ..$ Values: num [1:6] 35 37.5 40 42.5 45 47.5
+  ..$ lon  :List of 3
+  .. ..$ Type  : chr "Lon"
+  .. ..$ Units : chr "degrees east"
+  .. ..$ Values: num [1:9] -15 -12.5 -10 -7.5 -5 -2.5 0 2.5 5
+
+}}}
+
+As we can see, the variable T has vertical levels. In this case, the only level available is at 850 mb. The variable is daily, as we can see in the `TimeStep` element of the list, and the original units are Kelvin.
+
+There are several options for spatial selection using the 'loadData` function. For instance, if we want the whole domain of teh dataset ()
+
+
+
+= Using standard variables via vocabulary and dictionary =
+
+
+