####Using ESRI ascii grids as inputs...
nap "red = get_gridascii('red.ASC')";
nap "near = get_gridascii('near.ASC')";
nap_info seconds
nap "NDVI = (near-red)/(near+red)"
nap_info seconds
###Plot output to a jpeg file
plot_nao NDVI -print 1 -filename NDVI_asc.jpeg
###Ascii grids seem slower to parse, so let us use HDF files
nap "red = f32 "[nap_get hdf red.hdf "3-dimensional Scientific Dataset"]""
$red shape
nap "near = f32 [nap_get hdf near.hdf "3-dimensional Scientific Dataset"]"
nap "NDVI = (near-red)/(near+red)"
#nap_info seconds
###sanity check, NDVI NAO should have same shape as red or near NAO
$NDVI shape
plot_nao NDVI(,,0)
########Another approach, using a multi-band hdf, derived from a multiband geotiff using GDAL,
nap "all_bands = f32 [nap_get hdf all_bands.hdf "3-dimensional Scientific Dataset"]"
nap "red = all_bands(,,1)"
nap "near = all_bands(,,3)"
nap "NDVI = (near-red)/(near+red)"
plot_nao red -print 1 -filename red.jpg
plot_nao near -print 1 -filename near.jpg
plot_nao NDVI -print 1 -filename NDVI.jpgHere are the pictures:
