 # contour overlapping

Bala subramanian schrieb:

hai Armin,

I looked through the examples. I could not find any example of overlapping
two differnet countours on the same plot.

I think the first example filled contours does exactly that. You want to
show two contours over each other in the same plot.
You just have to substitute the Z in cset_1 with matrix_1 and in cset_2
with matrix_2. Of course it will be helpful to use different colormaps.
E.g. a grey one for the underlying contour and a colored for the top one.

x = arange(5)
y = arange(5)
x,y = meshgrid(x,y)
Z = x**2+y**2
#contourf(Z,cmap=cm.binary) # filled contours gray
contour(Z) # not filled contours colored
error = rand(x.shape,x.shape) # to generate a new Z
Z = (x+error)**2+(y+error)**2
contour(Z) # colored not filled contours

Armin

Armin,
I tried this but what happens is it is not overlapping, actually when i call contour function for the second time with matrix2, the plot is updated with contour of matrix 2.

contour(matrix1)
contour(matrix2).

What i finally get is the contour of matrix 2 as the final plot. What i am trying to do is that, i shd have one plot, with upper left panel for matrix1 and lower right panel for matrix2 with their separation along the diagonal. I have attached an example picture like which i am trying to make.

Bala ···

On Wed, May 13, 2009 at 5:33 PM, Armin Moser <armin.moser@…2495…> wrote:

Bala subramanian schrieb:

hai Armin,

I looked through the examples. I could not find any example of overlapping

two differnet countours on the same plot.

I think the first example filled contours does exactly that. You want to

show two contours over each other in the same plot.

You just have to substitute the Z in cset_1 with matrix_1 and in cset_2

with matrix_2. Of course it will be helpful to use different colormaps.

E.g. a grey one for the underlying contour and a colored for the top one.

x = arange(5)

y = arange(5)

x,y = meshgrid(x,y)

Z = x2+y2

#contourf(Z,cmap=cm.binary) # filled contours gray

contour(Z) # not filled contours colored

error = rand(x.shape,x.shape) # to generate a new Z

Z = (x+error)**2+(y+error)**2

contour(Z) # colored not filled contours

Armin

Hi Bala,

I'm not sure I understand, what you want, but maybe the following goes towards

# initialise two matrices with data
matrix1 = ones((4,4))
matrix2 = 2*ones((4,4))
# and one empty matrix
matrix3 = zeros((4, 4))

for i in xrange(len(matrix3[:, 0])): # all rows
for j in xrange(len(matrix3[0, :])):# all columns
if i > j: # if below diagonal take matrix1
matrix3[i, j] = matrix1[i, j]
elif i < j: # if above diagonal take matrix 2
matrix3[i, j] = matrix2[i, j]

In : print matrix3
Out:
array([[ 0., 2., 2., 2.],
[ 1., 0., 2., 2.],
[ 1., 1., 0., 2.],
[ 1., 1., 1., 0.]])

With that matrix3 holds elements of matrix2 in the upper part and elements of
matrix1 below the diagonal. This one could be plotted with contour or
contourf.

Is that what you want?

best regards Matthias

···

On Wednesday 13 May 2009 18:12:53 Bala subramanian wrote:

Armin,
I tried this but what happens is it is not overlapping, actually when i
call contour function for the second time with matrix2, the plot is updated
with contour of matrix 2.

contour(matrix1)
contour(matrix2).

What i finally get is the contour of matrix 2 as the final plot. What i am
trying to do is that, i shd have one plot, with upper left panel for
matrix1 and lower right panel for matrix2 with their separation along the
diagonal. I have attached an example picture like which i am trying to
make.

Bala

On Wed, May 13, 2009 at 5:33 PM, Armin Moser > > <armin.moser@...2495...>wrote:
> Bala subramanian schrieb:
> > hai Armin,
> >
> > I looked through the examples. I could not find any example of
>
> overlapping
>
> > two differnet countours on the same plot.
>
> I think the first example filled contours does exactly that. You want to
> show two contours over each other in the same plot.
> You just have to substitute the Z in cset_1 with matrix_1 and in cset_2
> with matrix_2. Of course it will be helpful to use different colormaps.
> E.g. a grey one for the underlying contour and a colored for the top one.
>
> x = arange(5)
> y = arange(5)
> x,y = meshgrid(x,y)
> Z = x**2+y**2
> #contourf(Z,cmap=cm.binary) # filled contours gray
> contour(Z) # not filled contours colored
> error = rand(x.shape,x.shape) # to generate a new Z
> Z = (x+error)**2+(y+error)**2
> contour(Z) # colored not filled contours
>
> Armin

Matthias Michler wrote:

...
for i in xrange(len(matrix3[:, 0])): # all rows
for j in xrange(len(matrix3[0, :])):# all columns
...

if your matrices a and b are rectangular (and i think the "diagonal"
makes only sense in this case), you can also say:

array([list(a[i,:i])+list(b[i,i:]) for i in range(a.shape)])

best,
sebastian.

p.s.: i think it would be a nice feature to put
"matplotlib-users@lists.sourceforge.net" as reply-to in the mails
distributed via the list -- i keep hitting the 'reply'-button and wonder
why my mails do not show up in the list...

Sebastian Busch wrote:

Matthias Michler wrote:

...
for i in xrange(len(matrix3[:, 0])): # all rows
for j in xrange(len(matrix3[0, :])):# all columns
...

if your matrices a and b are rectangular (and i think the "diagonal"
makes only sense in this case), you can also say:

array([list(a[i,:i])+list(b[i,i:]) for i in range(a.shape)])

It seems that I did not understand what you tried to reach. Sorry for
pointing into the wrong direction.

Another possibility would be to use masked arrays:

------------------------8<-------------------------------------
from pylab import *

x = arange(100)
y = arange(100)
x,y = meshgrid(x,y)
Z = x**2+y**2
# contour, imshow, pcolor do not show values at positions
# where the mask is True
contourf(Z,origin='lower')

error = rand(x.shape,x.shape)
Z = (x+error)**2+(y+error)**2
contourf(Z,cmap=cm.binary)
axis('tight')
show()

Thank you Matthias, Sebastin and Armin!!!

My matrices are square matrices and not rectangular one. I tried the way of creating a new matrix from existing ones as suggested by matthias and it worked great. I will try the masked array method too.

Thank you all once again,
Bala

···

On Wed, May 13, 2009 at 6:45 PM, Matthias Michler <MatthiasMichler@…361…> wrote:

Hi Bala,

I’m not sure I understand, what you want, but maybe the following goes towards

# initialise two matrices with data

matrix1 = ones((4,4))

matrix2 = 2*ones((4,4))

# and one empty matrix

matrix3 = zeros((4, 4))

for i in xrange(len(matrix3[:, 0])): # all rows

``````for j in xrange(len(matrix3[0, :])):# all columns

if i > j: # if below diagonal take matrix1

matrix3[i, j] = matrix1[i, j]

elif i < j: # if above diagonal take matrix 2

matrix3[i, j] = matrix2[i, j]
``````

In : print matrix3

Out:

array([[ 0., 2., 2., 2.],

``````       [ 1.,  0.,  2.,  2.],

[ 1.,  1.,  0.,  2.],

[ 1.,  1.,  1.,  0.]])
``````

With that matrix3 holds elements of matrix2 in the upper part and elements of

matrix1 below the diagonal. This one could be plotted with contour or

contourf.

Is that what you want?

best regards Matthias

On Wednesday 13 May 2009 18:12:53 Bala subramanian wrote:

Armin,

I tried this but what happens is it is not overlapping, actually when i

call contour function for the second time with matrix2, the plot is updated

with contour of matrix 2.

contour(matrix1)

contour(matrix2).

What i finally get is the contour of matrix 2 as the final plot. What i am

trying to do is that, i shd have one plot, with upper left panel for

matrix1 and lower right panel for matrix2 with their separation along the

diagonal. I have attached an example picture like which i am trying to

make.

Bala

On Wed, May 13, 2009 at 5:33 PM, Armin Moser > > > > > > <armin.moser@…2495…>wrote:

Bala subramanian schrieb:

hai Armin,

I looked through the examples. I could not find any example of

overlapping

two differnet countours on the same plot.

I think the first example filled contours does exactly that. You want to

show two contours over each other in the same plot.

You just have to substitute the Z in cset_1 with matrix_1 and in cset_2

with matrix_2. Of course it will be helpful to use different colormaps.

E.g. a grey one for the underlying contour and a colored for the top one.

x = arange(5)

y = arange(5)

x,y = meshgrid(x,y)

Z = x2+y2

#contourf(Z,cmap=cm.binary) # filled contours gray

contour(Z) # not filled contours colored

error = rand(x.shape,x.shape) # to generate a new Z

Z = (x+error)**2+(y+error)**2

contour(Z) # colored not filled contours

Armin

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Armin Moser wrote:

Sebastian Busch wrote:

...
array([list(a[i,:i])+list(b[i,i:]) for i in range(a.shape)])

It seems that I did not understand what you tried to reach.
...

Sorry. I wanted to do the same as Matthias -- taking his example:

···

=====
from scipy import ones, array

# matrix1 = ones((4,4)) matrix2 = 2*ones((4,4)) matrix3 = array([list(matrix1[i,:i])+list(matrix2[i,i:])\ for i in range(matrix1.shape)])

yields

matrix3
array([[ 2., 2., 2., 2.],
[ 1., 2., 2., 2.],
[ 1., 1., 2., 2.],
[ 1., 1., 1., 2.]])

it's quite the same, you just have to type less best,
sebastian.

Sebastian Busch schrieb:

Armin Moser wrote:

Sebastian Busch wrote:

...
array([list(a[i,:i])+list(b[i,i:]) for i in range(a.shape)])

It seems that I did not understand what you tried to reach.
...

Sorry. I wanted to do the same as Matthias -- taking his example:

I meant I did not understand in the first what Bala tried to reach. I