Re: [Matplotlib-users] [ANN] basemap matplotlib toolkit 0.1.1

[Jeff W. <js...@fa...>]

Ted Drain wrote:

> Jeff,
> Great timing!  I was just reviewing some requirements from our users 
> to be able to create ground track plots of spacecraft right after 
> launch.  Your package looks like it should easily do most of the work 
> for us!
>
> One thing I do need to be able to do is to create line plots that 
> "wrap around" a map.  We generate a lot of ground tracks that use a 
> Mercator projection covering the whole globe (x=-180->180, y=-90->90) 
> and if the line goes off one edge, we need to wrap it around to the 
> other edge instead of drawing a line segment all the way across the page.


Ted:   That is a pain - I had to work around this a couple of times in 
the basemap code (when drawing coastlines and when drawing parallels and 
meridians). 

BTW:  You won't be able to define a mercator projection that goes from 
-90 to 90 (it's singular at the poles).  You'll have to stop it at 80 or 
85 degrees.

>
> I had planning on creating a front end script to pre-process the data 
> to handle this type of capability.  The only issue with this approach 
> is that it requires multiple lines be drawn (as if you're plotting 
> multiple curves) but only one of them should show up in the legend.  I 
> was wondering anyone else has need of this and if there is a better 
> way to implement this wrapping feature when doing map plots?


That would be useful for lots of people I think - I don't know of any 
better way (other than using a non-cylindrical projection, like a polar 
stereographic).


-Jeff

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