On Tue, Jan 27, 2009 at 7:16 PM, Eli Brosh <ebro...@gmail.com> wrote:
> Many thanks to Jeff and to Patric !
> I will try to work along the line suggested by Jeff.
> Patric, please send me your code.
> I hope to learn from it.
>
> Thanks again,
> Eli
Here is a template that can be used. I use this for meteorological
models, but should work with any gridded file.
import numpy as np
from mpl_toolkits.basemap import Basemap
f = (some gridded file)
X = np.array(grab longitudes from f)
Y = np.array(grab latitudes from f)
field = np.array(grab field to be contoured from f)
map = Basemap(make a Basemap call here)
level = np.arange(minval, maxval, interval)
col = map.contour(X, Y, field, level).collections
for vertex in col[i].get_paths(): # GET THE PATHS FOR THE EACH
CONTOUR BY LOOPING THROUGH CONTOURS
for vertex in xy.vertices: # ITERATE OVER THE PATH OBJECTS
x, y = map(vertex[0],vertex[1],inverse=True) # vertex[0]
and now 'x' is the longitude of the vertex and vertex[1] and now 'y'
is the latitude of the vertex
Let me know how this works.
-Patrick
>
> On Tue, Jan 27, 2009 at 7:09 PM, Patrick Marsh <patrickmars...@gmail.com>
> wrote:
>>
>> On Tue, Jan 27, 2009 at 5:33 PM, Jeff Whitaker <jsw...@fastmail.fm> wrote:
>> > Eli Brosh wrote:
>> >> Hello,
>> >> I am trying to extract the coordinates of contour lines.
>> >> I tried the following:
>> >>
>> >> cs = *contour*(Z)
>> >> for lev, col in zip(cs.levels, cs.collections):
>> >> s = col._segments
>> >>
>> >> that I found in a previous post (title "contouring", by Jose
>> >> Gómez-Dans-2 <http://www.nabble.com/user/UserProfile.jtp?user=30071>
>> >> Nov 30, 2007; 07:47am ) .
>> >>
>> >> I hoped that s will be a list of numpy arrays, each containing the
>> >> (x,y) vertices
>> >> defining a contour line at level lev.
>> >> However, I got an error message:
>> >> AttributeError: 'LineCollection' object has no attribute '_segments'
>> >>
>> >>
>> >> How is it possible to get coordinates of the contours, similar to the
>> >> MATLAB command
>> >> [C,H] = *CONTOUR*(...)
>> >> where the result in C is the coordinates of the contours.
>> >>
>> >> A similar question appeared in a post "contour data" (by Albert Swart
>> >> <http://www.nabble.com/user/UserProfile.jtp?user=382945> May 17, 2006;
>> >> 09:42am) but I could not understand the answer.
>> >> Is it possible to get more specific directions with a simple example ?
>> >>
>> >>
>> >> Thanks
>> >> Eli
>> > Eli: Calling get_paths() on each line collection in CS.collections will
>> > return a list of Path objects. From the Path objects, you can get a Nx2
>> > array of vertices from the "vertices" attribute. There are no examples
>> > that I know of, but if you get it to do what you want to do, it would be
>> > great if you could contribute an example. As you noted, this question
>> > has come up several times before.
>> >
>> > -Jeff
>> >
>> > --
>> > Jeffrey S. Whitaker Phone : (303)497-6313
>> > Meteorologist FAX : (303)497-6449
>> > NOAA/OAR/PSD R/PSD1 Email : jeffrey.s.whita...@noaa.gov
>> > 325 Broadway Office : Skaggs Research Cntr 1D-113
>> > Boulder, CO, USA 80303-3328 Web : http://tinyurl.com/5telg
>> >
>> >
>> >
>> >
>> > ------------------------------------------------------------------------------
>> > This SF.net email is sponsored by:
>> > SourcForge Community
>> > SourceForge wants to tell your story.
>> > http://p.sf.net/sfu/sf-spreadtheword
>> > _______________________________________________
>> > Matplotlib-users mailing list
>> > Matplotlib-users@lists.sourceforge.net
>> > https://lists.sourceforge.net/lists/listinfo/matplotlib-users
>> >
>>
>> I'm not sure if this is entirely what you (Eli) are looking for, but I
>> have code that will contour model data on a map and then extract the
>> lat,lon pairs of all the vertices. If this is what you are looking
>> for, I'm happy to share what I've done.
>>
>> -Patrick
>>
>> --
>> Patrick Marsh
>> Graduate Research Assistant
>> School of Meteorology
>> University of Oklahoma
>> http://www.patricktmarsh.com
>
>
--
Patrick Marsh
Graduate Research Assistant
School of Meteorology
University of Oklahoma
http://www.patricktmarsh.com
------------------------------------------------------------------------------
This SF.net email is sponsored by:
SourcForge Community
SourceForge wants to tell your story.
http://p.sf.net/sfu/sf-spreadtheword
_______________________________________________
Matplotlib-users mailing list
Matplotlib-users@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/matplotlib-users
