# Polygon contains_point() different from matplotlib.nxutils.points_inside_poly?

I'm trying to test whether or not the origin is contained inside the following triangle
inscribed inside a circle:

th = array([ 2.3913423, 5.3133123, 1.8516171])
p=patch.Polygon(array([cos(th),sin(th)]).T)

p.contains_point((0,0))

returns 0

but,

matplotlib.nxutils.points_inside_poly([[0,0]],p.get_path().vertices)

returns True

What am I missing here?

Thanks!

I'm trying to test whether or not the origin is contained inside the
following triangle
inscribed inside a circle:

th = array([ 2.3913423, 5.3133123, 1.8516171])
p=patch.Polygon(array([cos(th),sin(th)]).T)

What do you mean by "patch" here?

I tested

p=Polygon(array([cos(th),sin(th)]).T)
p.contains_point((0,0))

Jerzy Karczmarczuk

···

Le 13/02/2012 17:47, reckoner a écrit :

Here's a better example:

th= array([ 4.65542641, 5.32920696, 2.20928291])
p=patch.Polygon(array([cos(th),sin(th)]).T)
print p.contains_point((0,0))

1

print matplotlib.nxutils.pnpoly(0,0,p.get_path().vertices)

0

Thanks!

···

On 2/13/2012 8:47 AM, reckoner wrote:

I'm trying to test whether or not the origin is contained inside the
following triangle
inscribed inside a circle:

th = array([ 2.3913423, 5.3133123, 1.8516171])
p=patch.Polygon(array([cos(th),sin(th)]).T)

p.contains_point((0,0))

returns 0

but,

matplotlib.nxutils.points_inside_poly([[0,0]],p.get_path().vertices)

returns True

What am I missing here?

Thanks!

I can confirm this for both the current development branch and v1.1.x. Strange…

Ben Root

···

On Mon, Feb 13, 2012 at 1:33 PM, reckoner <reckoner@…287…> wrote:

Here’s a better example:

th= array([ 4.65542641, 5.32920696, 2.20928291])

p=patch.Polygon(array([cos(th),sin(th)]).T)

print p.contains_point((0,0))

1

print matplotlib.nxutils.pnpoly(0,0,p.get_path().vertices)

0

Thanks!

reckoner:

``````      >>> th= array([ 4.65542641,  5.32920696,
``````

2.20928291])

``````      >>> p=patch.Polygon(array([cos(th),sin(th)]).T)

>>> print p.contains_point((0,0))

1

>>> print
``````

matplotlib.nxutils.pnpoly(0,0,p.get_path().vertices)

``````      0

Thanks!
``````
``````      I can confirm this for both the current development branch and
``````

v1.1.x. Strange…

``````      Ben Root
``````
``````HYPOTHESIS (I have no time to check now everything..., I did my
``````

best.)

``````If radius=None, it is converted into radius=1 in contains_point (in
``````

Patch).

``````(This is the linewidth !)

I am not sure whether it is ok, i.e. in pixels. If this value is
``````

considered to be relative to axes, it is enormous!

``````p.contains_point((0,0),radius=0.01)

gives 0 as it should.

Jerzy Karczmarczuk

P.S. I suggest anyway that reckoner submits a complete program with
``````

imports. What is “patch”??

Jerzy is right. contains() and contains_point() both takes a radius argument as this function is intended for use when mouse-clicking. If no radius is given, it uses the object’s linewidth and passes it to the path’s contains_point() function with its transform. I suspect that the problem is that the transforms haven’t been fully defined yet and might be incorrectly testing this.

This needs a bit more investigation to see if this is the intended behavior or if something needs to be fixed.

As a side note, “patch” is an imported module via “from matplotlib import patches as patch”. Not standard among mpl devs, but not out of the ordinary.

Ben Root

···

On Mon, Feb 13, 2012 at 2:59 PM, Jerzy Karczmarczuk <jerzy.karczmarczuk@…3937…> wrote:

reckoner:

``````      >>> th= array([ 4.65542641,  5.32920696,
``````

2.20928291])

``````      >>> p=patch.Polygon(array([cos(th),sin(th)]).T)

>>> print p.contains_point((0,0))

1

>>> print
``````

matplotlib.nxutils.pnpoly(0,0,p.get_path().vertices)

``````      0

Thanks!
``````
``````      I can confirm this for both the current development branch and
``````

v1.1.x. Strange…

``````      Ben Root
``````
``````HYPOTHESIS (I have no time to check now everything..., I did my
``````

best.)

``````If radius=None, it is converted into radius=1 in contains_point (in
``````

Patch).

``````(This is the linewidth !)

I am not sure whether it is ok, i.e. in pixels. If this value is
``````

considered to be relative to axes, it is enormous!

``````p.contains_point((0,0),radius=0.01)

gives 0 as it should.

Jerzy Karczmarczuk

P.S. I suggest anyway that reckoner submits a complete program with
``````

imports. What is “patch”??