Hi, everybody:
I don't have experience with images or contours and need some help plotting
a 'z' quantity for given x,y coordinates.
What are the choices?
Here is a small sample of the data:
The first row has the i-th x-coordinate at which the field starts to have
the value [i,j].
The first column has the j-th y-coordinate at which the field starts to
have the value [i,j].
The coordinate steps are not constant, nor the same for both dimensions;
they can be anything because they come from some odd finite difference
program.
My first shot at this is getting combersome, I am hoping for a better way.
So far, because the second decimal place in the x,y coordinate is alwasy
zero, I simply turned those coordinates into integers by multiplying by ten
and truncating; then by subtracting the first value from the rest, they look
very much like matrix indeces (except for the missing ones):
Then, because I don't know any better, I broadcast the values onto another
matrix, to fill in the in-between values:
Now, I have a matrix where every i,j has its own z-value and I am supposed
to be able to plot it with ax.contourf(mymatrix)...which I can, up until
about mymatrix[:,:1900] or so, afte that, I get the following error:
Traceback (most recent call last):
File "C:\findiff\t1.py", line 73, in <module>
ax.contourf(full[:,:2000])
File "C:\Python26\lib\site-packages\matplotlib\axes.py", line 7322, in
contourf
return mcontour.QuadContourSet(self, *args, **kwargs)
File "C:\Python26\lib\site-packages\matplotlib\contour.py", line 1106, in
__init__
ContourSet.__init__(self, ax, *args, **kwargs)
File "C:\Python26\lib\site-packages\matplotlib\contour.py", line 700, in
__init__
self._process_args(*args, **kwargs)
File "C:\Python26\lib\site-packages\matplotlib\contour.py", line 1130, in
_process_args
C = _cntr.Cntr(x, y, z.filled(), _mask)
ValueError: Arguments x, y, z, mask (if present) must be 2D arrays.
x, y, z must be castable to double.
My current matrix is about 12000x5000.
Any asistance would be greatly appreciated.
Thanks,
Germán
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