Description Usage Arguments Details Value Author(s) References See Also Examples
solarRad computes the solar radiation received at the top of the Earth's atmosphere on a horizontal surface. This radiation will change during the day and will be different at different latitudes and in different seasons.
1 2 | solarRad(img, day)
solarRad12M(img, outFl, ...)
|
img |
object of class SpatialGridDataFrame that provided a projection class and a bbox attributes. The nature of the data.frame that contains the attribute data is not relevant. It must be in geographic coordinates. |
day |
The number of the day (from 1 to 365) to compute extra-terrestrial radiation. |
outFl |
A list of 12 file names to save the results. |
... |
Any unmatched parameter will be passed to the writeGDAL routine. |
The output is expressed in cal/cm2*day.
This function runs unnoticed within petHgsm, but can be executed manually.
solarRad returns a single image corresponding to the specified day, as a SpatialGridDataFrame class. solarRad12M writes 12 images to disk in the format especified by the GDAL drivername parameter.
Gabriel del Barrio, Marieta SanJuan & Alberto Ruiz
Crop evapotranspiration - Guidelines for computing crop water requirements - FAO Irrigation and drainage paper 56
1 2 3 4 5 6 7 8 | #not run
#aux=readGDAL('iberia_mask')
#calc the extraterrestial radiation the 15-agost
#Rad=solarRad(aux,227)
#writeGDAL(Rad,'solarrad_15ago')
#or to calculate and write to disk, the radiation of the twelve months
#RadFileNames=paste('rad',month.abb,sep='')
#solarRad12M(img,RadFileNames)
|
Loading required package: rgdal
Loading required package: sp
rgdal: version: 1.2-10, (SVN revision 673)
Geospatial Data Abstraction Library extensions to R successfully loaded
Loaded GDAL runtime: GDAL 1.10.1, released 2013/08/26
Path to GDAL shared files: /usr/share/gdal/1.10
Loaded PROJ.4 runtime: Rel. 4.8.0, 6 March 2012, [PJ_VERSION: 480]
Path to PROJ.4 shared files: (autodetected)
WARNING: no proj_defs.dat in PROJ.4 shared files
Linking to sp version: 1.2-3
Loading required package: matrixStats
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