# Polar Photometry Plots?

You can see an example on the second page of <Lightolier | Signify. �Scroll down. �The plot is next to the table titled, "candlepower summary." �It's a quadrant rather than a full circle, and it's clipped to a box, but it's still a polar plot.

The only problem I have with what matplotlib does is that it seems determined to put zero at the right, rather than at the bottom. �I want to turn the axis 90 degrees.

Randolph

···

On 2010-03-02 14:50:51 -0800, Jae-Joon Lee said:

Do you have any link to an example plot?
I googled it but not much luck.
Is it like a polar plot without the bottom half?

Regards,

-JJ

On Tue, Mar 2, 2010 at 1:48 AM, R Fritz <rfritz@...1342...> wrote:
> I'd like to be able to generate type C photometry plots with
> matplotlib. The standard co-ordinate system for these has 0 degrees at
> the bottom (nadir) of the plot, with values increasing
> counterclockwise. Is there anyway I can transform the co-ordinates that
> matplotlib uses to do this?
> --

Randolph Fritz
> �design machine group, architecture department, university of washington
> rfritz@...1342... -or- rfritz333@...287...

The current implementation of PolarAxes does not support that.
However, you can workaround this easily using a custom axes.

ax = fig.add_axes([0.1, 0.1, 0.8, 0.8], polar=True, axisbg='#d5de9c')

use following code

from matplotlib.projections.polar import PolarAxes
from matplotlib.transforms import Affine2D

class PolarAxes2(PolarAxes):
def PolarTransform(self):
return Affine2D().translate(-.5*np.pi,0) + PolarAxes.PolarTransform()

ax = PolarAxes2(fig, [0.1, 0.1, 0.8, 0.8], axisbg='#d5de9c')

Regards,

-JJ

···

On Tue, Mar 2, 2010 at 8:44 PM, R Fritz <rfritz@...1342...> wrote:

You can see an example on the second page of
<Lightolier | Signify. Scroll down. The plot is
next to the table titled, "candlepower summary." It's a quadrant
rather than a full circle, and it's clipped to a box, but it's still a
polar plot.

The only problem I have with what matplotlib does is that it seems
determined to put zero at the right, rather than at the bottom. I want
to turn the axis 90 degrees.

Randolph

On 2010-03-02 14:50:51 -0800, Jae-Joon Lee said:

Do you have any link to an example plot?
I googled it but not much luck.
Is it like a polar plot without the bottom half?

Regards,

-JJ

On Tue, Mar 2, 2010 at 1:48 AM, R Fritz <rfritz@...1342...> wrote:
> I'd like to be able to generate type C photometry plots with
> matplotlib. The standard co-ordinate system for these has 0 degrees at
> the bottom (nadir) of the plot, with values increasing
> counterclockwise. Is there anyway I can transform the co-ordinates that
> matplotlib uses to do this?
> --

Randolph Fritz
> design machine group, architecture department, university of washington
> rfritz@...1342... -or- rfritz333@...287...

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