Re: [Matplotlib-users] Get contourf image as array

[David H. <dh...@gm...>]

For the first question, if I save the figure (as a PNG I'm guessing, 
unless you can save into a more array-like format), I'd have to make 
sure that there were no labels or ticks and that the axes fit the whole 
figure. I'd also have to get the dpi and size information correct, but I 
suppose it would be possible that way. I was hoping for something a 
little easier and in-memory. This might be the simplest answer the more 
I think about it.

If I'm starting from the paths, I'd still have to write them to the 
"grid" array. I thought maybe the backend could do that and I magically 
get the image.

I'll look in to using savefig and getting the data out.

-Dave

On 10/15/14, 12:42 PM, Joy merwin monteiro wrote:
> pardon the query if it seems dumb, but why don't you do a savefig()
> after plotting the data and then convert it to any format you like?
>
> alternatively, contour() and contourf() both create paths that can
> be accessed:
>
> cf = contourf(.....)
>
> output = cf.collections.pop()
> paths = output.get_paths()[i] # for the various contours
>
> the x,y coordinates can then be accessed as
>
> xcoords = paths.vertices.transpose()[0]
> ycoords = paths.vertices.transpose()[1]
>
> you can then do whatever you wish with them.
>
> Joy
>
>
> On Wed, Oct 15, 2014 at 9:11 PM, David Hoese <dh...@gm...
> <mailto:dh...@gm...>> wrote:
>
>     I've been searching and reading through source code and google searches
>     to see if this is possible, but no luck so far. I'm basically trying to
>     map some data using Basemap, use contourf to map it to an image, and
>     then put that image in a geotiff (or other format) for use in other GIS
>     programs. I have other tools for remapping data and creating geotiffs,
>     but the contour image looks better. All I would need to get this to work
>     would be an array representing the image inside the axes of a contourf
>     plot. I found a lot of geotiff -> Basemap png results, but I would like
>     the reverse.
>
>     Since the plots are made using paths/patches I'm guessing I would have
>     to have a backend render the image and then extract the image somehow.
>     Does anyone have some tips or tricks to do something like this? Or am I
>     thinking about this completely wrong?
>
>     Thanks for any help and if you could CC me in any replies it would be
>     much appreciated.
>
>     -Dave
>
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