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

[Matt F. <mat...@gm...>]

On 9/9/2011 6:42 AM, Scott Sinclair wrote:
> 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..
I have been using gdal for many of my geographic needs. Is there an
advantage/disadvantage using pyproj vs capabilities found in gdal (from
what i understand both are based on PROJ.4)? Can you comment on this?
Also, i was thinking of projecting things to UTM for interpolation
purposes. Is there any apparent reason this is a bad idea vs a different
projected coordinate system?

matt

>
> Cheers,
> Scott
>
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-- 
Matt Funk
Research Associate
Plant and Environmental Scienc. Dept.
New Mexico State University