On Wed, Sep 29, 2010 at 16:00, John Hunter <jdh2358@gmail.com> wrote:

This is not correct, either. Since the total width of the image is 800 pixels and the total height is 600 pixels, I get the following coordinates of the yellow dot:

x-coord: = 432

y-coord = 600-576 = 24

but in fact, the position of the yellow dot is still at (720, 60)!. (And even if you swapped x and y coordinates it will never be correct.).

So anyone another idea how to transform a data-point (10,20) to the image coordinates?

Cheers

Alex

On Wed, Sep 29, 2010 at 8:50 AM, Alexander DietzWhy do you say it's wrong? Note that in mpl, (0,0) is (bottom left),

<Alexander.Dietz72@googlemail.com> wrote:

> print ax.transData.transform((10.0, 20.0))

> [ 576. 432.]

not (upper,left). So this is saying that the yellow dot at 10,20

(data coords) is 576 pixels up from the bottom and 432 pixels over

from the left.

This is not correct, either. Since the total width of the image is 800 pixels and the total height is 600 pixels, I get the following coordinates of the yellow dot:

x-coord: = 432

y-coord = 600-576 = 24

but in fact, the position of the yellow dot is still at (720, 60)!. (And even if you swapped x and y coordinates it will never be correct.).

So anyone another idea how to transform a data-point (10,20) to the image coordinates?

Cheers

Alex

JDH