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Thanks a lot Eric,
your demo works excellent!
Petr

I forgot to include that I am speaking about the vertical/y axis. 

In my application, I am creating a second axes using pylab's twinx and plot 
various lines on both axes. I'd like to take advantage of the automatic 
change of the line color that happens when using the plot() command. 
Unfortunately, this is done only within one axes i.e. when plotting on the 
other axes, the first line color is used again. This results in multiple 
lines that have the some color.
Is there a smart way to make Matplotlib use the next color in sequence for 
the first line on a new axes?
As is:
Axes 1
- Line 1 (blue)
- Line 2 (green)
Axes 2
- Line 1 (blue)
- Line 2 (green)
To be:
Axes 1
- Line 1 (blue)
- Line 2 (green)
Axes 2
- Line 1 (red)
- Line 2 (light blue)
Thanks,
Sascha 

I am having some issues creating axis labels. When I set 
horizontalalignment='right' (which is the default), the y axis label is 
positioned correctly for the left axis. Using 'center', the text is 
positioned too close to the axis so that multiline text runs into the tick 
labels. For the right axis (created with pylab.twinx(), it's the other way 
around - 'right' is too close to the tick labels and 'center' works better.
Any hints what I can do to position the labels correctly?
Thanks,
Sascha 

Petr Jakes wrote:
>Hi all,
>using the basemap module, I would like to import my own image (scanned
>paper map) as a background layer and than plot my GPS data on it. I
>would like to know:
>
>1) if it is possible in general?
>if yes:
>2) are there any good examples or suggestion which way to go and how
> to do it?
>
>Thanks for your postings
>
>Petr Jakes
>
> 
>
Petr: You can easily plot data on arbitrary map projections, there are 
many examples of this in the source distribution and the wiki 
(http://www.scipy.org/wikis/topical_software/Maps). Using your own 
image as a background will be trickier, in fact I've never tried it. 
Basemap comes with it's own data (coastlines, political boundaries and 
rivers) for drawing maps. However, you may be able to do it by 
importing your image using PIL, converting it to a Numeric array and 
then plotting it over the map projection using imshow. To see how to 
convert an image to and from a Numeric array see 
http://effbot.org/zone/pil-numpy.htm. To see how to plot an image with 
Basemap see http://matplotlib.sourceforge.net/screenshots/plotmap.py. 
If you do get this to work, please post an example to the list. I'm 
sure many would be interested.
-Jeff
-- 
Jeffrey S. Whitaker Phone : (303)497-6313
NOAA/OAR/CDC R/CDC1 FAX : (303)497-6449
325 Broadway Web : http://www.cdc.noaa.gov/~jsw
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Mark, Petr,
> 
> I would like to plot the line which interconnects the GPS track points
> (latitude and longitude coordinates) recorded by GPS receiver. It is
> not so difficult. What I am not able to do is to change the color of
> the line according to the speed reached on the way from point to
> point. I would like to use the color of the line to differentiate the
> speed as following:
> 
> speed <=50km/h
> speed >50 and <=90km/h
> speed >90 and <=130km/h
> speed >130km/h
It can be done, but not with a simple plot command. See the attached 
demo; I think it is similar to what you want to do.
Eric