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Hello,

I've been having a problem in my basemap plots of areas with small spatial
extents, where my meridians are cutoff like so:

<http://matplotlib.1069221.n5.nabble.com/file/n41409/Max_Water_Surface.png> 

I've tried simplifying the code as much as possible, but still get a similar
problem:
<http://matplotlib.1069221.n5.nabble.com/file/n41409/meridians_cutoff_atTop.png> 

The meridians plot correctly when I use a normal mercator  instead of the
transverse mercator projection, so switching to mercator is my last resort
option for now.  Has anyone dealt with this problem before and found a
workaround?

Thank you!
-SeanPaul

Here's my simplified code:

import numpy as np
import matplotlib as mpl
from mpl_toolkits.basemap import Basemap
import matplotlib.pyplot as plt


"""Input desired lats (y) and lons(x) of plot"""
############
xmin = -166.22
xmax = -166.134

ymin = 53.7439
ymax = 53.7827
############

m = Basemap(projection='tmerc', lon_0=-165. , lat_0=0 , llcrnrlon=xmin,
llcrnrlat=ymin, urcrnrlon=xmax , urcrnrlat=ymax)

meridians = np.arange(xmin,xmax,(30/3600)) # 30 arcsecond spacing
m.drawmeridians(meridians)

parallels = np.arange(ymin,ymax,(30/3600))
m.drawparallels(parallels)

plt.show()



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Hello list,

I have LineCollection object: "l = matplotlib.collections.LineCollection()" which I want to save as image without any kind of margins.

What have I tried is following:

ax = plt.subplot(111)
ax.set_axis_off()
ax.add_collection(l)
ax.autoscale_view()
plt.savefig('img.png')

but there are still unwanted margins.

How to plot without margins?


Thanks

> kmanross <mailto:kev...@gm...>
> July 2, 2013 12:42 PM
> Greetings!
>
> Relative newbie here.
>
> I'm trying to plot wind vectors using basemap quiver and to fit my ortho
> projection. This is essentially a hack of Jeff Whitaker's animate.py found
> at
>
> https://github.com/matplotlib/basemap/blob/master/examples/animate.py
>
> The data source I'm connecting to, however, has the latitudes in 
> decreasing
> order, so I get the "lats and lons must be in increasing order!" exception
> when trying to use the transform_vector method which seems to be 
> required to
> fit the vectors to the projection. (ugliness occurs when failing to
> transform)
>
> What would be the best way to transform latitudes (to increasing) as 
> needed
> by transform_vector, while also accounting for the data order of my u 
> and v
> grids?
>
> -kevin.
>

Kevin:  Just flip the data around.

lats_flipped = lats[::-1,:]
data_flipeed = data[::-1,:] # assuming 2d array shape (nlats,nlons)


-Jeff
>
>
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Yes, but this is where I am failing. I don't have the code with me right 
now but I can explain it:

I get a new number every 2000 milliseconds, and I want to update the 
graph say, every 50 milliseconds, and keep a minute of history visible 
in the graph.

So that's 30 x-axis ticks.

But if I want to draw this out smoothly, I need 40 more ticks per update 
interval. I have five lines I want to show, so every 50ms, 600 points 
need to be plotted out.

Now, my proof of concept code is just working with arrays in a sort of 
FIFO queue, I haven't actually tried to plug those arrays into 
matplotlib, but it seems like replotting 600 points is a lot of work.

Maybe I am over reacting? Or is there some feature of matplotlib that 
allows me to push data onto a plot instead of replotting all points?

I dunno, I'm not confident in my approach. I seek inspiration.

thanks,
--alex

This means that every 50ms, 600 points need to be updated.

On 13-07-04 05:11 PM, Michael Droettboom wrote:
> I see -- you want to basically interpolate between points?  I don't 
> think there's anything built in to matplotlib to do that, but you 
> could always do that interpolation outside and just update the graph 
> more often.
>
> Mike
>
> On 07/04/2013 04:28 PM, v0idnull wrote:
>> eh....
>>
>> Let me explain my problem in a different way:
>>
>> Every two seconds I get a value from a service. Let's say I over 8 
>> seconds I get 1, 5, 10, 5 as values.
>>
>> So if my application updates the graph every two seconds, this will 
>> look choppy and ugly. This is because every two seconds, an entire 
>> line is added onto the graph between the two points.
>>
>> Imagine if I could control the drawing of said line though. If I 
>> could draw the individual pixels of the line every couple of ticks 
>> instead of just dumping a line in every two seconds, I will end up 
>> with a nice smooth animation. It may not be 100% real time anymore, 
>> but my focus on this personal project of mine is vanity, not 
>> practicality ;)
>>
>> I hope this better explains what I am trying to accomplish...
>>
>> Thanks,
>> --alex
>>
>> On 13-07-04 04:09 PM, Michael Droettboom wrote:
>>> Have you looked at the simple_anim.py example -- other than the 
>>> networking piece, it seems to do what you describe, and it's pretty 
>>> fast. Maybe start from that and make changes until it gets slow in 
>>> order to determine where the slowness comes from...?
>>>
>>> Mike
>>>
>>> On 07/03/2013 09:19 PM, v0idnull wrote:
>>>> I am receiving a number from a server every two seconds. I would 
>>>> like to plot this number.out over time for the past say... 30 polls.
>>>>
>>>> Would it be possible to use... Anything, to produce a smooth 
>>>> animation of the plot line getting drawn? As it stands now the 
>>>> animation is well... Quite choppy. ;)
>>>>
>>>> I'm using pygame currently to render my graphs on this full screen 
>>>> application I'm making just for my self. I am not bound to it 
>>>> though if there are better linux-only things out there.
>>>>
>>>> Thanks in advance,
>>>> --alex
>>>>
>>>>
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I want to plot current data on a map. I wrote that :



But it returns me only one arrow According to the using of the shape
function I guess my slice is right :



What can I do to have all the arrows? (It's a global world file..)



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