matplotlib-users Mailing List for matplotlib

The automatic docstring generation for this command is badly fouled up, 
and I can't straighten it out right now. In the meantime, look at the 
docstring for FancyArrow.__init__ in patches.py. There is also a 
horrendously complicated example in examples/arrow_demo.py.
Depending on what you want to do, you might find the annotate command to 
be what you want. I think its docstring is in better shape, as its 
example: examples/annotate_demo.py.
Eric
Jessica Lu wrote:
> I usually use the following to make single arrows:
> 
> plot([0,1], 'k.')
> arr1 = pylab.Arrow(0.5, 0.5, 0.1, 0.0, width=0.02)
> fig = pylab.gca()
> fig.add_patch(arr1)
> 
> 
> If in "ipython -pylab" you need to savefig or send another command (e.g. 
> xlabel) or reload/refresh the plot (I can't remember the command) for 
> the new patch to display. I use this rather than arrow() because I can 
> control the arrow width and other properties. There is also the quiver 
> command which lets you draw many arrows:
> 
> quiver([[0, 1, 2]], [[0, 1, 2]], [[0.0, 0.0, 0.0]], [[0.1, 0.1, 0.1]], 0.2)
> 
> Cheers,
> Jessica
> 
> On Jul 20, 2007, at 6:32 AM, Alexander Dietz wrote:
> 
>> Hi,
>>
>> How is the syntax for the matplotlib command 'arrow'? There is not 
>> very much to take from the help (see below). An example would be nice.
>>
>> Thanks
>> Alex
>> 
>> In [46]: arrow?
>> Type: function
>> Base Class: <type 'function'>
>> String Form: <function arrow at 0xb77f8a3c>
>> Namespace: Interactive
>> File: /usr/lib/python2.4/site-packages/matplotlib/pylab.py
>> Definition: arrow(*args, **kwargs)
>> Docstring:
>> Draws arrow on specified axis from (x,y) to (x+dx,y+dy).
>> Optional kwargs control the arrow properties:
>> alpha: float
>> animated: [True | False]
>> antialiased or aa: [True | False]
>> axes: an axes instance
>> clip_box: a matplotlib.transform.Bbox instance
>> clip_on: [True | False]
>> clip_path: an agg.path_storage instance
>> edgecolor or ec: any matplotlib color
>> facecolor or fc: any matplotlib color
>> figure: a matplotlib.figure.Figure instance
>> fill: [True | False]
>> hatch: unknown
>> label: any string
>> linewidth or lw: float
>> lod: [True | False]
>> picker: [None|float|boolean|callable]
>> transform: a matplotlib.transform transformation instance
>> visible: [True | False]
>> zorder: any number
>>
>> Addition kwargs: hold = [True|False] overrides default hold state
>>
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> 
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I usually use the following to make single arrows:
plot([0,1], 'k.')
arr1 = pylab.Arrow(0.5, 0.5, 0.1, 0.0, width=0.02)
fig = pylab.gca()
fig.add_patch(arr1)
If in "ipython -pylab" you need to savefig or send another command 
(e.g. xlabel) or reload/refresh the plot (I can't remember the 
command) for the new patch to display. I use this rather than arrow() 
because I can control the arrow width and other properties. There is 
also the quiver command which lets you draw many arrows:
quiver([[0, 1, 2]], [[0, 1, 2]], [[0.0, 0.0, 0.0]], [[0.1, 0.1, 
0.1]], 0.2)
Cheers,
Jessica
On Jul 20, 2007, at 6:32 AM, Alexander Dietz wrote:
> Hi,
>
> How is the syntax for the matplotlib command 'arrow'? There is not 
> very much to take from the help (see below). An example would be nice.
>
> Thanks
> Alex
>
> In [46]: arrow?
> Type: function
> Base Class: <type 'function'>
> String Form: <function arrow at 0xb77f8a3c>
> Namespace: Interactive
> File: /usr/lib/python2.4/site-packages/matplotlib/pylab.py
> Definition: arrow(*args, **kwargs)
> Docstring:
> Draws arrow on specified axis from (x,y) to (x+dx,y+dy).
> Optional kwargs control the arrow properties:
> alpha: float
> animated: [True | False]
> antialiased or aa: [True | False]
> axes: an axes instance
> clip_box: a matplotlib.transform.Bbox instance
> clip_on: [True | False]
> clip_path: an agg.path_storage instance
> edgecolor or ec: any matplotlib color
> facecolor or fc: any matplotlib color
> figure: a matplotlib.figure.Figure instance
> fill: [True | False]
> hatch: unknown
> label: any string
> linewidth or lw: float
> lod: [True | False]
> picker: [None|float|boolean|callable]
> transform: a matplotlib.transform transformation instance
> visible: [True | False]
> zorder: any number
>
> Addition kwargs: hold = [True|False] overrides default hold state
>
> ---------------------------------------------------------------------- 
> ---
> This SF.net email is sponsored by: Microsoft
> Defy all challenges. Microsoft(R) Visual Studio 2005.
> http://clk.atdmt.com/MRT/go/vse0120000070mrt/direct/01/ 
> _______________________________________________
> Matplotlib-users mailing list
> Mat...@li...
> https://lists.sourceforge.net/lists/listinfo/matplotlib-users

Hi,
 I wanted to plot a graph with a grid background and an x axis ranging =
from 0 -16 and a y axis ranging from 0 -16. I used the following code:
from pylab import*
xlabel('time (s)')
ylabel('voltage (mV)')
title('About as simple as it gets, folks')
grid(True)
axis([-16,16,-16,16])
show()
However, both axes were scaled in intervals of 5 automatically, ranging =
from -15 - 15. Although the axes began and end at -16 & 16 respectively, =
the number 16 or -16 is not shown. How do I resacle the axis to ensure =
16 & -16 are shown and the grid is not cut off at each axes? How do I =
control the interval size on each scale to change it from an interval =
size of 5 to lets say 2? Is it possible to control grid size?
Jonathan.

Default flat would be great. The default faceted has always been a pain.
George.

Eric Firing wrote:
> Consistent with matlab, the default shading for pcolor in matplotlib and 
> pylab is 'faceted', which puts black lines around all the 
> quadrilaterals. Some users (e.g., Rob Hetland and myself) never want 
> this; are there users who *do* want to keep this default? I suspect so, 
> in which case the solution will be an rcParams entry, but I would like 
> confirmation of this. Also, if we need the rcParams entry but *almost* 
> all users want the default to be "flat" (no boundary lines), then we can 
> make that the default value of the rcParams entry.
> 
> Please advise.
> 
(Sent to the list this time.)
+1 for default 'flat' (either way)
Ryan
-- 
Ryan May
Graduate Research Assistant
School of Meteorology
University of Oklahoma

Consistent with matlab, the default shading for pcolor in matplotlib and 
pylab is 'faceted', which puts black lines around all the 
quadrilaterals. Some users (e.g., Rob Hetland and myself) never want 
this; are there users who *do* want to keep this default? I suspect so, 
in which case the solution will be an rcParams entry, but I would like 
confirmation of this. Also, if we need the rcParams entry but *almost* 
all users want the default to be "flat" (no boundary lines), then we can 
make that the default value of the rcParams entry.
Please advise.
Thanks.
Eric

Matthew Auger <ma...@ph...>
writes:
> Hi...I'm interested in plotting text elements with the X value in data 
> coordinates and the Y value in axis coordinates
See <http://www.scipy.org/Cookbook/Matplotlib/Transformations>.
-- 
Jouni K. Seppänen
http://www.iki.fi/jks

Hi,
How is the syntax for the matplotlib command 'arrow'? There is not very much
to take from the help (see below). An example would be nice.
Thanks
 Alex
In [46]: arrow?
Type: function
Base Class: <type 'function'>
String Form: <function arrow at 0xb77f8a3c>
Namespace: Interactive
File: /usr/lib/python2.4/site-packages/matplotlib/pylab.py
Definition: arrow(*args, **kwargs)
Docstring:
 Draws arrow on specified axis from (x,y) to (x+dx,y+dy).
 Optional kwargs control the arrow properties:
 alpha: float
 animated: [True | False]
 antialiased or aa: [True | False]
 axes: an axes instance
 clip_box: a matplotlib.transform.Bbox instance
 clip_on: [True | False]
 clip_path: an agg.path_storage instance
 edgecolor or ec: any matplotlib color
 facecolor or fc: any matplotlib color
 figure: a matplotlib.figure.Figure instance
 fill: [True | False]
 hatch: unknown
 label: any string
 linewidth or lw: float
 lod: [True | False]
 picker: [None|float|boolean|callable]
 transform: a matplotlib.transform transformation instance
 visible: [True | False]
 zorder: any number
 Addition kwargs: hold = [True|False] overrides default hold state

Hi...I'm interested in plotting text elements with the X value in data 
coordinates and the Y value in axis coordinates (in this way I could plot 
labels at the top of the axes that would respond to zooming/panning in the 
X-direction but would *always* remain at the top of the axes as long as 
the X-coord was still in the axes, for example). Is this possible?
Also, it seems the only differences between axvline and vlines are that 
vlines can take multiple lines as input and vlines uses data coords to set 
the y limits while axvline uses axis coords. It seems simpler to have one 
function that takes an optional argument to choose whether to use data or 
axis coordinates for the y range (and maybe even for the x value...ie 
producing the same functionality that I seek above).
Thanks for any help/suggestions!
Matt