The following example uses the "Unidata" sample netCDF dataset of eastward wind which can be downloaded from here (2.8 MB)
I have two lists of integers that correspond to the x and y index of a gridded array in a netCDF file. I want to extract the data and save it to a 1 dimensional array or list for each of the point combinations (e.g. points: [(x[0],y[0]), (x[1],y[1]), (x[2],y[2]), ... , (x[n],y[n])]).
I can do this quite easily using this method...
from netCDF4 import Dataset
# grid point lists
lat = [20, 45, 56, 67, 88, 98, 115]
lon = [32, 38, 48, 58, 87, 92, 143]
# open netCDF file
nc_file = "./sresa1b_ncar_ccsm3-example.nc"
fh = Dataset(nc_file, mode='r')
# extract variable
point_list = zip(lat,lon)
ua_list = []
for i, j in point_list:
ua_list.append(fh.variables['ua'][0,16,i,j])
print(ua_list)
Which returns:
[59.29171, 17.413916, -4.4006901, -11.15424, -5.2684789, 2.1235929, -6.134573]
However append() is clunky on big datasets and I'm trying to speed up my code so I also do not want to use a for loop and would rather return the results in a single line. I've tried doing so using this line:
# extract variable
ua_array = fh.variables['ua'][0,16,lat,lon]
print(ua_array)
Which returns every single possible combination of points instead of just the ones I am after:
[[ 59.2917099 60.3418541 61.81352234 62.66215515 60.6419754 60.00745392 52.48550797]
[ 18.80122566 17.41391563 14.83201313 12.67425823 13.99616718 14.4371767 14.12419605]
[ -5.56457043 -5.20643377 -4.40069008 -3.25902319 -2.36573601 -2.25667071 -1.0884304 ]
[-11.66207981 -11.46785831 -11.35252953 -11.15423965 -11.35271263 -11.55139542 -11.68573093]
[ -1.15064895 -1.52471519 -2.12152767 -2.67548943 -5.26847887 -5.79328251 -6.16713762]
[ -1.95770085 -0.56232995 0.82722098 1.39629912 2.65125418 2.12359285 -6.47501516]
[ -9.76508904 -10.13490105 -10.76805496 -11.31607246 -11.93865585 -11.56440639 -6.13457298]]
How can I slice the netCDF file so I can get the same result as the above code in a single line? Thanks in advance.
