Thanks for confirming that I'm not the only one having trouble with IRIS installation. Such a pain!
Back to the first question, I figured that the NCEP Reanalysis data has the y axis "from 90N to 90S", means the indexing started from north (90), not south (-90), which means that my calculation was on 5 S instead of 5 N. Fadzil Postgraduate Student Room 1U09 - Dept of Meteorology University of Reading, Earley Gate Reading RG6 6BB, UK On Wed, Oct 15, 2014 at 10:04 PM, Benjamin Root <[email protected]> wrote: > Stephen is being a bit modest by putting xray last in the list. I > recommend it, and it is very painless to install. I could only get iris > installed via a SciTools repo on binstar and even then, I had to tinker > with a few things to get it working (and it was only the linux binaries, > too). > > Ben Root > > On Wed, Oct 15, 2014 at 3:44 PM, Chris Barker <[email protected]> > wrote: > >> On Tue, Oct 14, 2014 at 11:30 AM, Fadzil Mnor <[email protected]> >> wrote: >> >>> I've been trying to install IRIS on my laptop (OS X) for months. Errors >>> everywhere. >>> I'll look at that IRIS again, and other links. >>> >> >> IRIS has been an install challeng,e but gotten better. >> >> And you ay even find a conda package for it if you use Anaconda -- I put >> one up during Scipy -- they may be a newer build, though. >> >> -Chris >> >> >> >> >>> Cheers, >>> >>> >>> Fadzil >>> >>> On Tue, Oct 14, 2014 at 7:09 PM, Stephan Hoyer <[email protected]> wrote: >>> >>>> Hi Fadzil, >>>> >>>> My strong recommendation is that you don't just use numpy/netCDF4 to >>>> process your data, but rather use one of a multitude of packages that have >>>> been developed specifically to facilitate working with labeled data from >>>> netCDF files: >>>> - Iris: http://scitools.org.uk/iris/ >>>> - CDAT: http://uvcdat.llnl.gov/ >>>> - xray (my project): http://xray.readthedocs.org >>>> >>>> I can't answer your specific question without taking a careful look at >>>> your data, but in very general terms, your code will have fewer bugs if you >>>> can use meaningful labels to refer to your data rather than numeric ranges >>>> like 396:757:12. >>>> >>>> Best, >>>> Stephan >>>> >>>> >>>> On Tue, Oct 14, 2014 at 3:50 AM, Fadzil Mnor <[email protected]> >>>> wrote: >>>> >>>>> Hi all, >>>>> I wrote a script and plot monthly mean zonal wind (from a netcdf file >>>>> names uwnd.mon.mean.nc) and I'm not sure if I'm doing it correctly. >>>>> What I have: >>>>> >>>>> >>>>> ******************************************************************************** >>>>> *#this part calculates mean values for january only, from 1980-2010; >>>>> thus the index looks like this 396:757:12* >>>>> >>>>> def ujan(): >>>>> f = nc.Dataset('~/data/ncep/uwnd.mon.mean.nc') >>>>> u10_1 = f.variables['uwnd'] >>>>> u10_2 = np.mean(u10_1[396:757:12,:,38,39:43],axis=0) >>>>> return u10_2 >>>>> >>>>> uJan = ujan()* #calling function* >>>>> >>>>> *#this part is only to define lon, lat and level * >>>>> q = nc.Dataset('~/data/ncep/uwnd.mon.mean.nc') >>>>> lon=q.variables['lon'] >>>>> lat=q.variables['lat'] >>>>> lev=q.variables['level'] >>>>> >>>>> *#for some reason I need to define this unless it gave error "length >>>>> of x must be number of column in z"* >>>>> >>>>> lon=lon[39:43] >>>>> >>>>> *#begin plotting* >>>>> >>>>> clevs=np.arange(-10.,10.,0.5) >>>>> fig = plt.figure(figsize=(11, 8)) >>>>> fig.clf() >>>>> ax = fig.add_subplot(111) >>>>> ax.axis([97.5, 105., 1000., 10.]) >>>>> ax.tick_params(direction='out', which='both') >>>>> ax.set_xlabel('Lon (degrees)') >>>>> ax.set_ylabel('Pressure (mb)') >>>>> ax.set_xticks(np.arange(97.5, 105., .5)) >>>>> ax.set_yticks([1000, 700, 500, 300, 100, 10]) >>>>> cs=ax.contourf(lon, lev, uJan, clevs, extend='both',cmap='seismic') >>>>> plt.title('Zonal winds average (Jan, 1981-2010)') >>>>> cax = fig.add_axes([0.99, 0.1, 0.03, 0.8]) >>>>> aa=fig.colorbar(cs,cax=cax,orientation='vertical') >>>>> aa.set_label('m/s') >>>>> plt.savefig('~/uwind-crossection-test.png', bbox_inches='tight') >>>>> >>>>> ******************************************************************************* >>>>> >>>>> the result is attached. >>>>> I have no idea how to confirm the result (at least until this email is >>>>> written) , but I believe the lower altitude values should be mostly >>>>> negative, because over this region, the zonal wind are usually easterly >>>>> (thus,negative values), but I got positive values. >>>>> >>>>> Put the information above aside, *I just want to know if my slicing >>>>> in the ujan() function is correct*. If it is, then, there must be >>>>> nothing wrong(except my above mentioned assumption). >>>>> The data file dimension is: >>>>> *[time,level,latitude,longitude]* >>>>> >>>>> This part: >>>>> *u10_2 = np.mean(u10_1[396:757:12,:,38,39:43],axis=0)* >>>>> The line above will calculate the mean of zonal wind (uwnd) in a range >>>>> of time index 396 to 757 for each year (january only), for all vertical >>>>> level, at latitude index 38 (5 N) and in between longitude index 39 to 43 >>>>> (97.5E-105E). >>>>> I assume it will calculate a 30-year average of zonal wind for january >>>>> only. >>>>> Is this correct? >>>>> >>>>> Thank you. >>>>> >>>>> Fadzil >>>>> >>>>> _______________________________________________ >>>>> NumPy-Discussion mailing list >>>>> [email protected] >>>>> http://mail.scipy.org/mailman/listinfo/numpy-discussion >>>>> >>>>> >>>> >>>> _______________________________________________ >>>> NumPy-Discussion mailing list >>>> [email protected] >>>> http://mail.scipy.org/mailman/listinfo/numpy-discussion >>>> >>>> >>> >>> _______________________________________________ >>> NumPy-Discussion mailing list >>> [email protected] >>> http://mail.scipy.org/mailman/listinfo/numpy-discussion >>> >>> >> >> >> -- >> >> Christopher Barker, Ph.D. >> Oceanographer >> >> Emergency Response Division >> NOAA/NOS/OR&R (206) 526-6959 voice >> 7600 Sand Point Way NE (206) 526-6329 fax >> Seattle, WA 98115 (206) 526-6317 main reception >> >> [email protected] >> >> _______________________________________________ >> NumPy-Discussion mailing list >> [email protected] >> http://mail.scipy.org/mailman/listinfo/numpy-discussion >> >> > > _______________________________________________ > NumPy-Discussion mailing list > [email protected] > http://mail.scipy.org/mailman/listinfo/numpy-discussion > >
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