On 3/7/11 2:25 PM, Juan A. Saenz wrote: > Jeff, thanks for your reply. > > One situation where one might require masked nearest neighbor > interpolation is when, on a given fixed grid, interpolating velocities > on cell corners (B-grid) to faces (C-grid). Cells will be defined as > either land or ocean cells, masked or un-masked respectively. The > masked or un-masked character of cells does not change. Interpolating > velocities from corners adjacent to masked cells, to cell centers on > un-masked cells will require the behavior in question. Imagine two > adjacent cells, one masked and the other not. The velocities on the > cell corners that lie on the coast (adjacent to a masked and an > un-masked cell) are masked. A desireable behavior of the interpolator > would be to produce an un-masked cell centered velocity on the > un-masked cell that uses values from adjacent un-masked velocity values. > > Thanks, > Juan >
Juan: I can see why you want it in this case, but I think in general users would expect a masked value if the nearest neighbor is masked. In addition, I don't see how to implement it easily. How far are you willing to go to find a nearest neighbor that is not masked? In short, for your use case you'll have to implement your own custom solution. Of course, if you can show me a simple modification to the Basemap interp function that does what you want, and can be enabled with a kwarg, I'll reconsider. -Jeff > > On 8/03/11 12:23 AM, Jeff Whitaker wrote: >> On 3/7/11 5:50 AM, Jeff Whitaker wrote: >>> On 3/6/11 8:58 PM, Juan A. Saenz wrote: >>>> Hi, >>>> >>>> I use Basemap and netCDF4-python on a regular basis, and find them >>>> very useful tools. Thank you for developing them! >>>> >>>> I noticed that when using basemap.interp for nearest neighbor >>>> (order=0) the interpolation is not masked, and nearest neighbor masked >>>> values will be used in the interpolation. I was wondering if you could >>>> suggest a way to do nearest neighbor interpolation where masked are >>>> supported, i.e. nearest neighbor values that are not masked. >>>> >>>> Thanks for your help, >>>> Juan >>>> >>> Juan: I agree that this would be desirable behavior. Unfortunately, >>> it's not obvious to me how to do it. I'll think about it and get back >>> to you. (cc'ing matplotlib-users list). >>> >>> -Jeff >>> >> >> Juan: On second thought, I'm not sure this is desirable behavior. I >> would guess that most of the time, if a nearest neighbor is masked, >> the user would expect the interpolation routine to return a masked >> value. I would be interested to hear what others think. >> >> -Jeff >> > > -- 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 ------------------------------------------------------------------------------ What You Don't Know About Data Connectivity CAN Hurt You This paper provides an overview of data connectivity, details its effect on application quality, and explores various alternative solutions. http://p.sf.net/sfu/progress-d2d _______________________________________________ Matplotlib-users mailing list Matplotlib-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/matplotlib-users
