Jeff, this is great, works fine - many thanks for all your help over the last few days, it really is appreciated. I'm trying to build the case within my office for switching over to Basemap from IDL, ironing out niggles like this is really useful in this respect.
All the best, Will. Jeff Whitaker wrote: > > On 4/5/10 7:25 AM, Will Hewson wrote: >> I should perhaps of explained my code (included in top post) a little >> better, >> the values in my attached file aren't on a regular grid to start with, I >> do >> a little bit of juggling as follows to get them into a regular grid: >> >> I'm firstly setting up my 2D grid of 0.5 degree lat lons, followed by >> identically sized grids of zeros for the data bin, and mean divisors: >> >> x = np.arange(-180, 180, 0.5); y = np.arange(-90, 90, 0.5) >> grid_lon, grid_lat = np.meshgrid(x,y) #regularly spaced 2D grid >> n_vals = np.zeros((360,720)) #mean divisor >> dat = np.zeros((360,720)) #2D grid of zeros >> >> I'm then taking my input data (e.g. the .plt file attached), and rounding >> the lat lons to the nearest 0 or 0.5: >> >> lon = (np.around(lon*2))/2 #round to nearest .0 or 0.5 >> lat = (np.around(lat*2))/2 #round to nearest .0 or 0.5 >> >> Then for each row in my input file where Z is greater than 0, I'm adding >> the >> n'th Z value to its corresponding position in the dat zeros array, and >> keeping a count of how many values are going into each cell in the mean >> divisor array: >> >> j=0 >> for i in slcol: >> if lon[j]< 0: >> grid_lon_ind = 360+(lon[j]*2) >> grid_lat_ind = 180+(lat[j]*2) >> else: >> grid_lon_ind = 360-(lon[j]*2) >> grid_lat_ind = 180+(lat[j]*2) >> if i> 0: >> dat[grid_lat_ind, grid_lon_ind] += i #add i'th value >> n_vals[grid_lat_ind, grid_lon_ind] += 1 #increase cell counter by 1 >> for >> each extra value >> j+=1 >> >> Finally the new dat array is divided by the mean divisor array to give me >> my >> mean Z values: >> >> dat = np.nan_to_num(dat/n_vals) >> >> I've done it this way as opposed to interpolating *properly* in order to >> (for instance) stop the values bleeding away from the edges of the >> satellite >> swath. >> >> Cheers, >> >> Will. >> > > Will: I made some slight modifications to your original script and it > works fine with the ortho projection using either contourf on the > original lat/lon grid or pcolormesh on the interpolated map projection > grid. > > -Jeff >> >> Jeff Whitaker wrote: >> >>> On 4/5/10 4:16 AM, Will Hewson wrote: >>> >>>> Hey Jeff, >>>> >>>> It's somewhere between the two - the original satellite swath is >>>> converted >>>> to a regular 0.5 degree grid by truncating, binning, and averaging each >>>> point's lons and lats over the top of a 720 x 360 np.zeros array. the >>>> plotting still works fine for non ortho/ hemispherical projections, and >>>> I've >>>> no big problem with using global projections for the time being. Thanks >>>> for >>>> your help in the meantime anyway. >>>> >>>> Cheers, >>>> >>>> >>>> Will. >>>> >>>> >>> Will: If it's a regular 0.5 degree lat/lon grid, it should work in >>> transform_scalar. However, I don't see how to read the data in your >>> test.plt file into a regular 360x720 grid. It seems to only contain the >>> points in the swath with nonzero values. >>> >>> -Jeff >>> >>>> >>>> Jeff Whitaker wrote: >>>> >>>> >>>>> On 4/4/10 11:06 AM, Will Hewson wrote: >>>>> >>>>> >>>>>> Hi again Jeff et al... >>>>>> >>>>>> I've had a play around with the extra few lines of code - on paper >>>>>> this >>>>>> seems like it should solve the problems I'm experiencing. However, an >>>>>> error's being thrown up by the transform scalar function, as my lons >>>>>> and >>>>>> lats won't necessarily be increasing. The data I'm plotting is >>>>>> satellite >>>>>> data and so at the beginning and end of the orbit file lats go over >>>>>> the >>>>>> pole >>>>>> from 90 to -90, with a similar problem for the lons - whereby the >>>>>> data >>>>>> is >>>>>> taken across the satellite track. I've thought about sorting the data >>>>>> before >>>>>> passing it to transform_scalar but I'm always going to be left with >>>>>> the >>>>>> problem in either lats or lons. >>>>>> >>>>>> I've uploaded the file I'm currently working with this time. It's >>>>>> three >>>>>> columns of lons, lats and z values. >>>>>> >>>>>> Once again, many thanks for your help. >>>>>> >>>>>> Will. >>>>>> >>>>>> http://old.nabble.com/file/p28133659/test.plt test.plt >>>>>> >>>>>> >>>>>> >>>>> Will: Is it a regular lat/lon grid or a satellite swath? If it's the >>>>> latter, you can't use my solution. >>>>> >>>>> -Jeff >>>>> >>>>> >>>>> ------------------------------------------------------------------------------ >>>>> Download Intel® Parallel Studio Eval >>>>> Try the new software tools for yourself. Speed compiling, find bugs >>>>> proactively, and fine-tune applications for parallel performance. >>>>> See why Intel Parallel Studio got high marks during beta. >>>>> http://p.sf.net/sfu/intel-sw-dev >>>>> _______________________________________________ >>>>> Matplotlib-users mailing list >>>>> Matplotlib-users@lists.sourceforge.net >>>>> https://lists.sourceforge.net/lists/listinfo/matplotlib-users >>>>> >>>>> >>>>> >>>>> >>>> >>>> >>> >>> ------------------------------------------------------------------------------ >>> Download Intel® Parallel Studio Eval >>> Try the new software tools for yourself. Speed compiling, find bugs >>> proactively, and fine-tune applications for parallel performance. >>> See why Intel Parallel Studio got high marks during beta. >>> http://p.sf.net/sfu/intel-sw-dev >>> _______________________________________________ >>> Matplotlib-users mailing list >>> Matplotlib-users@lists.sourceforge.net >>> https://lists.sourceforge.net/lists/listinfo/matplotlib-users >>> >>> >>> >> > > > -- > Jeffrey S. Whitaker Phone : (303)497-6313 > Meteorologist FAX : (303)497-6449 > NOAA/OAR/PSD R/PSD1 Email : jeffrey.s.whita...@noaa.gov > 325 Broadway Office : Skaggs Research Cntr 1D-113 > Boulder, CO, USA 80303-3328 Web : http://tinyurl.com/5telg > > > > ------------------------------------------------------------------------------ > Download Intel® Parallel Studio Eval > Try the new software tools for yourself. Speed compiling, find bugs > proactively, and fine-tune applications for parallel performance. > See why Intel Parallel Studio got high marks during beta. > http://p.sf.net/sfu/intel-sw-dev > _______________________________________________ > Matplotlib-users mailing list > Matplotlib-users@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/matplotlib-users > > -- View this message in context: http://old.nabble.com/Basemap--orthographic-projection-plot-doesn%27t-respect-globe-boundary-tp28117654p28141052.html Sent from the matplotlib - users mailing list archive at Nabble.com. ------------------------------------------------------------------------------ Download Intel® Parallel Studio Eval Try the new software tools for yourself. Speed compiling, find bugs proactively, and fine-tune applications for parallel performance. 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