Hey Jeff, I've got it sorted out a bit now. You're right the data was an output from Degrib and I had the option to output the csv's with or without data in the land areas. As before I was using a program that was placing the pixels in an image based on the X and Y columns it didn't create an issue. That was an easy fix by switching the option in the Degrib export.
Also by looking at your example I realized the way the contourf function requests the Z data and by just reshaping the array I was able to make all the stuff work properly. Numpy is amazing by the way! I had no idea how easy you can work with huge arrays! My new issue is that I need to mask the land areas in the Z array so I would have a clean plot over the basemap. Any ideas on how to achieve that? Thanks, Anton Jeff Whitaker wrote: > > antonv wrote: >> It seems that I just cannot grasp the way the data needs to be formatted >> for >> this to work... >> I've used the griddata sample that James posted but it takes about 10 >> minutes to prep the data for plotting so that solution seems to be out of >> discussion. >> >> I guess my issue is that I don't know what type of data is required by >> contourf function. Also as Jeff was saying earlier, the data is read from >> a >> grib file so supposedly it's already gridded. I've also looked at the >> basemap demo >> (http://matplotlib.sourceforge.net/users/screenshots.html#basemap-demo) >> and >> the data is read from 3 files, one for Lat one for Long and the Last for >> Z >> Data. Is there a way to automatically extract the data from the grib file >> to >> a format similar to the one used in the basemap example? >> > > Anton: I just looked at your csv file and I think I know what the > problem is. Whatever program you used to dump the grib data did not > write all the data - the missing land values were skipped. That means > you don't have the full rectangular array of data. I think you have two > choices: > > 1) insert the missing land values into the array, either in the csv file > or into the array after it is read in from the csv file. What program > did you use to dump the GRIB data to a CSV file? > > 2) use a python grib interface. If you're on Windows, PyNIO won't > work. I've written my own module (pygrib2 - > http://code.google.com/p/pygrib2) which you should be able to compile on > windows. You'll need the png and jasper (jpeg2000) libraries, however. > > I recommend (2) - in the time you've already spent messing with that csv > file, you could have already gotten a real python grib reader working! > > -Jeff >> >> >> Jeff Whitaker wrote: >> >>> Mauro Cavalcanti wrote: >>> >>>> Dear Anton, >>>> >>>> 2008/12/23 antonv <vasilescu_an...@yahoo.com>: >>>> >>>> >>>>> Also, because I figured out the data I need and already have the >>>>> scripts in place >>>>> to extract the CSV files I would really like to keep it that way. >>>>> Would >>>>> it be possible to >>>>> just show me how to get from the csv file to the plot? >>>>> >>>>> >>>> Here is a short recipe: >>>> >>>> import numpy as np >>>> >>>> f = open("file.csv", "r") >>>> coords = np.loadtxt(f, delimiter=",", skiprows=1) >>>> lon = coords[:,0] >>>> lat = coords[:,1] >>>> dat = coords[:,2] >>>> >>>> where "file.csv" is a regular comma-separated values file in the >>>> format: >>>> >>>> Lat,Lon,Dat >>>> -61.05,10.4,20 >>>> -79.43,9.15,50 >>>> -70.66,9.53,10 >>>> -63.11,7.91,40 >>>> ... >>>> >>>> Hope this helps! >>>> >>>> Best regards, >>>> >>>> >>>> >>> Since the arrays are 2D (for gridded data), a reshape is also needed, >>> i.e. >>> >>> lon.shape = (nlats,nlons) >>> lat.shape = (nlats,nlons) >>> data.shape = (nlats,nlons) >>> >>> You'll need to know what the grid dimensons (nlats,nlons) are. >>> >>> -Jeff >>> >>> ------------------------------------------------------------------------------ >>> _______________________________________________ >>> Matplotlib-users mailing list >>> Matplotlib-users@lists.sourceforge.net >>> https://lists.sourceforge.net/lists/listinfo/matplotlib-users >>> >>> >>> >> >> > > > ------------------------------------------------------------------------------ > _______________________________________________ > Matplotlib-users mailing list > Matplotlib-users@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/matplotlib-users > > -- View this message in context: http://www.nabble.com/Plotting-NOAA-data...-tp21139727p21199108.html Sent from the matplotlib - users mailing list archive at Nabble.com. ------------------------------------------------------------------------------ _______________________________________________ Matplotlib-users mailing list Matplotlib-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/matplotlib-users
