Re: [Matplotlib-users] retrieve a value at from projected data at a specific lon/lat?

[Eric F. <ef...@ha...>]

On 06/10/2010 04:41 AM, Mike Bauer wrote:
> Hello,
>
> Is there a way to get the data value at a specific longitude/latitude
> from an array that has been projected and smoothed with basemap and
> transform_scalar to a higher grid density?
>
> My original data is a global lat,lon array (73,144) that I process by
> hemisphere with a polar centered 'laea' projection (limited to 15
> degrees in each hemisphere). The data is also
> run through transform_scalar w/ say the result array being (180,360).
> What I want is a way to either get the data value at lon=x,lat=y from
> this array or a way to map the indices (180,360) such that
> I know index i,j is bound by a set of latitudes and longitudes.
>

Not sure I understand completely, but note that a basemap instance is a 
callable.  By default it transforms from lon,lat to map coordinates, but 
it also takes a kwarg, 'inverse'.  If true, to transforms back from map 
coordinates to lon,lat.  If your data have been transformed to a regular 
grid in map coordinates, this should allow you to find out what those 
grid cells are in lon,lat.

Eric

> Thanks for any suggestions.
>
> Mike
>
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