Re: [Matplotlib-users] it is possible to use basemap to create regular spaced lat/lon grids?

[Scott S. <sco...@gm...>]

On 8 September 2011 19:20, Matt Funk <mat...@gm...> wrote:
> Hi,
> sorry that it has taken me so long to reply. Anyway, i could be wrong, but i
> don't think that the code:
>     xi = np.linspace(llcrnlon,urcrnlon,1000)
>     yi = np.linspace(llcrnlat,urcrnlat,1000)
>
> will produce a grid which gives the lat/lon coordinates with 1km spacing.
> The reason being is that the distance between 2 lons (say -117.731659 and
> -91.303642) is different depending on where you are in terms of the latitude
> (i.e. the extreme examples are of course the north pole vs the equator). So
> the above gives a regular grid in terms of degrees but not in terms of
> distance.

Yes, that's correct. You'll need to project your original data
locations into a cartesian co-ordinate system before interpolating
their values onto a regular grid in that co-ordinate system using
griddata et al.

You might like to use pyproj (included with the basemap toolkit) to
help you project from lat/lon to your chosen co-ordinate system..

Cheers,
Scott