Jeff, I totally agree this is due to missing values
Again I've got difficulties to find good words so forgive me, what I tried to say is that the ability to have that border transparent would be a good feature in next releases, for people who need to interpolate and plot such data and have an aesthetic result Imshow is the ideal candidate for satellite data as it has some nice interpolation features and it is fast, so it can be batch-run on the server every time we receive data, without too much computation time The alternative I'm using now is a double or quadruple size grid to reduce the width of that border, with background color set to the lower colormap color That way, the border is really hard to see and it makes (almost) quality plots for publications -----Original Message----- From: Jeff Whitaker [mailto:[EMAIL PROTECTED] Sent: Thursday, 25 September, 2008 15:34 To: De Pauw Antoine Cc: 'Matplotlib Users' Subject: Re: [Matplotlib-users] Information request De Pauw Antoine wrote: > Jeff, > > Thanks for the tip, it's now working perfectly > > However, there's still that border with the imshow plot, and I think it > would be good to have it transparent > > There's a zoomed picture I made: > http://img218.imageshack.us/img218/5833/imshowborderxz9.png > > You see the shadow around the data... > > It would be nice for next releases of Matplotlib to get rid of that, but I'm > not able to patch it myself or so... I know there's still a lot of work with > the lib but keep the good work, it is really fantastic > > Thanks for your help! > > Antoine De Pauw > Collaborateur de recherches, Informatique - Research collaborator, IT > Laboratoire de chimie quantique et photophysique - Quantum chemistry and > photophysics laboratory > Université Libre de Bruxelles - ULB > Antoine: I thought we agreed that it's not an imshow bug - but rather due to the griddata gridding procedure returning missing values outside the convex hull of the input data. Do you disagree? I see no such border around an imshow plot that contains no missing values. If you shrink the size of the map plotting region so it's fully within the convex hull of the data, the border disappears. -Jeff > -----Original Message----- > From: Jeff Whitaker [mailto:[EMAIL PROTECTED] > Sent: jeudi 25 septembre 2008 14:15 > To: De Pauw Antoine > Cc: 'Matplotlib Users' > Subject: Re: [Matplotlib-users] Information request > > De Pauw Antoine wrote: > >> Hi Jeff, >> >> I finally found out how to fill my figure with a background color using >> axes.set_axis_bgcolor(color), but I'm facing the following problem now: >> >> How could I get the lower color of a colormap? This is quite undocumented >> and I dont know the colormap properties I could use for that >> >> I know there must be an accessible value somewhere, like for the >> ax.get_yticklabels() you gave me >> >> If someone had the clue, my problems would then be completely solved >> >> Antoine De Pauw >> Collaborateur de recherches, Informatique - Research collaborator, IT >> Laboratoire de chimie quantique et photophysique - Quantum chemistry and >> photophysics laboratory >> Université Libre de Bruxelles - ULB >> >> > > Antoine: To get the RGBA value associated with a particular data value, > just call the colormap as a function as pass it that value. For example > > >>> import matplotlib.pyplot as plt > >>> plt.cm.jet(1) > (0.0, 0.0, 0.517825311942959, 1.0) > > BTW: the 'fill_color' kwarg of drawmapboundary basemap method allows you > to set the background color of the map. > > http://matplotlib.sourceforge.net/basemap/doc/html/api/basemap_api.html > > It fills only the map region (which for some projections, like the > orthographic, is not the same as the axes region). > > > -Jeff > >> -----Original Message----- >> From: Jeff Whitaker [mailto:[EMAIL PROTECTED] >> Sent: mardi 23 septembre 2008 20:38 >> To: De Pauw Antoine >> Cc: 'John Hunter'; 'Matplotlib Users' >> Subject: Re: [Matplotlib-users] Information request >> >> De Pauw Antoine wrote: >> >> >>> Jeff, >>> >>> I still don't know how to either remove this artifact or fill my arrays >>> >>> >> with >> >> >>> values to remove empty regions, and I'll make a last attempt to resolve >>> > it > >>> I uploaded a data file here: http://scqp.ulb.ac.be/20080821.b56 >>> >>> The actual code snippet is here: >>> http://snipplr.com/view/8307/map-plotting-python-code-temporary/ >>> >>> I hope you'll be able to reproduce it, I set the cmap to winter for you >>> > to > >>> see the gap... setting it to hot will make the grayish border visible in >>> high resolution by zooming it... I think the border (not the empty zone) >>> could be an artifact with the hot colormap >>> >>> >>> Antoine De Pauw >>> Collaborateur de recherches, Informatique - Research collaborator, IT >>> Laboratoire de chimie quantique et photophysique - Quantum chemistry and >>> photophysics laboratory >>> Université Libre de Bruxelles - ULB >>> >>> >>> >>> >> Antoine: Here is a version that just plots the pixels directly, without >> interpolating to a grid. I personally like this better, since you can >> easily see where you actually have data. >> >> HTH, >> >> -Jeff >> >> from mpl_toolkits.basemap import Basemap >> import matplotlib.pyplot as plt >> import matplotlib.mlab as mlab >> import numpy as np >> import os >> fileName = '20080821.b56' >> titre='SO2' >> legende='Delta Brightness Temperature (K)' >> nbreligne=long(os.stat(fileName)[6])/(8*int(fileName[-2:])) >> rawfile=np.fromfile(open(fileName,'rb'),'<d',-1) >> Lat=rawfile[0:nbreligne] >> Lon=rawfile[nbreligne:nbreligne*2] >> Val=rawfile[nbreligne*21:nbreligne*22] >> map=Basemap(projection='mill',llcrnrlat=-90,urcrnrlat=90,\ >> urcrnrlon=180,llcrnrlon=-180,resolution='l') >> x, y = map(Lon, Lat) >> >> > plt.scatter(x,y,s=25,c=Val,marker='s',edgecolor="None",cmap=plt.cm.winter,vm > >> in=-5,vmax=-1.2, >> alpha=0.5) >> cb=plt.colorbar(shrink=0.6) >> cb.ax.set_ylabel(legende,fontsize=11) >> for t in cb.ax.get_yticklabels(): >> t.set_fontsize(7) >> meridians = np.arange(-180,180,60) >> parallels = np.arange(-90,90,30) >> map.drawparallels(parallels,labels=[1,0,0,0],fontsize=7,linewidth=0.25) >> map.drawmeridians(meridians,labels=[0,0,0,1],fontsize=7,linewidth=0.25) >> map.drawcoastlines(0.25,antialiased=1) >> plt.title(titre) >> plt.show() >> >> >>> -----Original Message----- >>> From: Jeff Whitaker [mailto:[EMAIL PROTECTED] >>> Sent: lundi 22 septembre 2008 13:59 >>> To: De Pauw Antoine >>> Cc: 'John Hunter'; 'Matplotlib Users' >>> Subject: Re: [Matplotlib-users] Information request >>> >>> De Pauw Antoine wrote: >>> >>> >>> >>>> Jeff, >>>> >>>> I included here a figure where you'll see the border problem for imshow >>>> >>>> >> in >> >> >>>> my case >>>> >>>> http://img217.imageshack.us/img217/5240/testfigzp3.png >>>> >>>> The border wraps at -180 and 180 to form the white line >>>> >>>> PS: it is atmospheric ice and not SO2, I just omitted to change the >>>> > title > >>>> >>>> >>>> >>> ^^ >>> >>> >>> >>>> Antoine De Pauw >>>> Collaborateur de recherches, Informatique - Research collaborator, IT >>>> Laboratoire de chimie quantique et photophysique - Quantum chemistry and >>>> photophysics laboratory >>>> Université Libre de Bruxelles - ULB >>>> >>>> >>>> >>>> >>> Antoine: I hate to keep repeating myself - but we can't do much if you >>> don't provide a self-contained script, that I can run, which reproduces >>> the problem. My guess is that the line along the dateline, and the >>> point at the South Pole are missing values (which griddata set to >>> missing because they are outside the extent of the data) - but that's >>> just a guess until I can reproduce it. >>> >>> -Jeff >>> >>> >>> >>>> -----Original Message----- >>>> From: Antoine De Pauw [mailto:[EMAIL PROTECTED] >>>> Sent: jeudi 18 septembre 2008 17:23 >>>> To: Jeff Whitaker; [EMAIL PROTECTED] >>>> Cc: 'John Hunter'; 'Matplotlib Users' >>>> Subject: re:Re: [Matplotlib-users] Information request >>>> >>>> Jeff, >>>> >>>> No the example doesn't show that line >>>> >>>> If I reduce the amount of data, the border will be on every side of the >>>> >>>> >>>> >>> plot >>> >>> >>> >>>> I'll show you an orthographic plot with no maskinf tomorrow and you will >>>> >>>> >>>> >>> see >>> >>> >>> >>>> the problem easily, it wraps in a white line along the 0° meridian and a >>>> white circle in the pole >>>> >>>> I think it's the imshow layer that is not totally transparent on the map >>>> background.. I tried every trick I could for example to put some >>>> >>>> >>>> >>> zero-valued >>> >>> >>> >>>> points on each corner to make imshow interpolate correctly the sides, >>>> > but > >>>> that doesn't make any difference >>>> >>>> >>>> >>>> >>>> >>>>> De Pauw Antoine wrote: >>>>> >>>>> >>>>> >>>>> >>>>>> Jeff, >>>>>> >>>>>> Yes they disappear, and they fluctuate with the interpolation method >>>>>> >>>>>> >>>>>> >>> used >>> >>> >>> >>>>>> For example, nearest interpolation don't show the line >>>>>> >>>>>> Also, if I reduce the grid resolution, the line is thicker, and if I >>>>>> >>>>>> >> use >> >> >>>>>> >>>>>> >>>>>> >>>>>> >>>> a >>>> >>>> >>>> >>>> >>>>>> masked array to get rid of undesired values, the border shows really >>>>>> strongly >>>>>> >>>>>> Here's an example everyone will see: >>>>>> >>>>>> http://img225.imageshack.us/img225/2671/testfigep2.png >>>>>> >>>>>> (everything except the clouds is noise) >>>>>> >>>>>> Antoine De Pauw >>>>>> Collaborateur de recherches, Informatique - Research collaborator, IT >>>>>> Laboratoire de chimie quantique et photophysique - Quantum chemistry >>>>>> >>>>>> >> and >> >> >>>>>> photophysics laboratory >>>>>> Université Libre de Bruxelles - ULB >>>>>> >>>>>> >>>>>> >>>>>> >>>>>> >>>>> Antoine: Sorry to seem dense, but I don't see anything wrong with that >>>>> > > >>>>> plot. I see a white border along the north and south pole, but I >>>>> intrepret that to be missing values. However, my eyes are notoriously >>>>> bad. I'd like to be to run a script that generates the artifacts >>>>> myself, so I can zoom in and see the problem myself. Does the >>>>> griddata_demo.py script show the same problem for you? >>>>> >>>>> -Jeff >>>>> >>>>> >>>>> >>>>> >>>>>> -----Original Message----- >>>>>> From: Jeff Whitaker [mailto:[EMAIL PROTECTED] >>>>>> Sent: mercredi 17 septembre 2008 19:05 >>>>>> To: John Hunter >>>>>> Cc: De Pauw Antoine; Matplotlib Users >>>>>> Subject: Re: [Matplotlib-users] Information request >>>>>> >>>>>> John Hunter wrote: >>>>>> >>>>>> >>>>>> >>>>>> >>>>>> >>>>>>> On Wed, Sep 17, 2008 at 11:54 AM, John Hunter <[EMAIL PROTECTED]> >>>>>>> >>>>>>> >>>>>>> >>> wrote: >>> >>> >>> >>>>>>> >>>>>>> >>>>>>> >>>>>>> >>>>>>> >>>>>>> >>>>>>>> Attached is a screenshot (zoom.png) from the gimp, zoomed in near >>>>>>>> > the > >>>>>>>> axes border. The black horizontal line is the top axes border, the >>>>>>>> horizontal grey line is the artifact, the vertical dashed line is a >>>>>>>> grid line. I don't know if this offers a clue, but if you look at a >>>>>>>> zoom in the upper right corner, the grey line seems to break up and >>>>>>>> curve down and to the right (corner.png) >>>>>>>> >>>>>>>> >>>>>>>> >>>>>>>> >>>>>>>> >>>>>>>> >>>>>>> Sorry, screwed up corner.png (I attached the original and not the >>>>>>> screenshot). The correct screenshot is attached >>>>>>> >>>>>>> >>>>>>> >>>>>>> >>>>>>> >>>>>>> >>>>>>> >>>>>>> >>>>>> John: OK, now I finally see it. Antoine: Do these artifacts >>>>>> disappear if you comment out the imshow call? >>>>>> >>>>>> -Jeff >>>>>> >>>>>> >>>>>> >>>>>> >>>>>> >>>>>> >>>>> -- >>>>> Jeffrey S. Whitaker Phone : (303)497-6313 >>>>> Meteorologist FAX : (303)497-6449 >>>>> NOAA/OAR/PSD R/PSD1 Email : [EMAIL PROTECTED] >>>>> 325 Broadway Office : Skaggs Research Cntr 1D-113 >>>>> Boulder, CO, USA 80303-3328 Web : http://tinyurl.com/5telg >>>>> >>>>> >>>>> >>>>> >>>>> >>>>> >>>>> >>>> >>>> >>>> >>>> >>> >>> >>> >> >> > > > -- Jeffrey S. Whitaker Phone : (303)497-6313 NOAA/OAR/CDC R/PSD1 FAX : (303)497-6449 325 Broadway Boulder, CO, USA 80305-3328 ------------------------------------------------------------------------- This SF.Net email is sponsored by the Moblin Your Move Developer's challenge Build the coolest Linux based applications with Moblin SDK & win great prizes Grand prize is a trip for two to an Open Source event anywhere in the world http://moblin-contest.org/redirect.php?banner_id=100&url=/ _______________________________________________ Matplotlib-users mailing list Matplotlib-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/matplotlib-users
