| PLOT3D format input [message #90620] |
Tue, 17 March 2015 18:04  |
lucesmm
Messages: 26
Registered: October 2014
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Junior Member |
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Hello
I am using PLOT3D
and when the format of my x,y,z vectors is
X FLOAT = Array[200]
Y FLOAT = Array[200]
Z FLOAT = Array[200]
it works
Now, when the format of the vectors is
X FLOAT = Array[1, 108]
Y FLOAT = Array[1, 108]
Z FLOAT = Array[1, 108]
it doesn't work and IDL says that
% Expression must be a scalar or 1 element array in this context: <BYTE Array[2]>
any idea what is happening, my original data is in a (9,108) array. how do I convert them ... this is similar to my code, t is generated from other software
t=FINDGEN(5,200)
x = COS(t) * (1 + t / 10)
help, x
p = PLOT3D(x(0,*), x(1,*), x(2,*),'o')
t=FINDGEN(5,200)
x = t(1,*)
y = t(2,*)
z = t(3,*)
help, x,y,z
p = PLOT3D(x, y, z,'o')
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| Re: PLOT3D format input [message #90621 is a reply to message #90620] |
Tue, 17 March 2015 19:49  |
Matthew Argall
Messages: 286
Registered: October 2011
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Senior Member |
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> t=FINDGEN(5,200)
> x = t(1,*)
> y = t(2,*)
> z = t(3,*)
>
> p = PLOT3D(x, y, z,'o')
I have found that function graphics are particularly picky about whether you pass them a column vector or row vector. Problems arise when you pass data in as a row vector (a 1xN array, as you are doing above). The solution is to reform your data into a column vector (Nx1 array), like so
x = reform(t[1,*])
y = reform(t[2,*])
z = reform(t[3,*])
p = plot3d(x, y, z, 'o')
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| Re: PLOT3D format input [message #90622 is a reply to message #90621] |
Tue, 17 March 2015 20:17 |
David Fanning
Messages: 11724
Registered: August 2001
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Senior Member |
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Matthew Argall writes:
>
>> t=FINDGEN(5,200)
>> x = t(1,*)
>> y = t(2,*)
>> z = t(3,*)
>>
>> p = PLOT3D(x, y, z,'o')
>
>
> I have found that function graphics are particularly picky about whether you pass them a column vector or row vector. Problems arise when you pass data in as a row vector (a 1xN array, as you are doing above). The solution is to reform your data into a column vector (Nx1 array), like so
>
> x = reform(t[1,*])
> y = reform(t[2,*])
> z = reform(t[3,*])
>
> p = plot3d(x, y, z, 'o')
Actually, visa versa, but we get the idea. :-)
x = t[1,*] is a column vector.
y = Reform(t[2,*]) is a row vector.
Cheers,
David
--
David Fanning, Ph.D.
Fanning Software Consulting, Inc.
Coyote's Guide to IDL Programming: http://www.idlcoyote.com/
Sepore ma de ni thue. ("Perhaps thou speakest truth.")
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| Re: PLOT3D format input [message #90626 is a reply to message #90621] |
Wed, 18 March 2015 12:38 |
Paul Van Delst[1]
Messages: 1157
Registered: April 2002
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Senior Member |
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Hello,
On 03/17/15 22:49, Matthew Argall wrote:
>> t=FINDGEN(5,200)
>> x = t(1,*)
>> y = t(2,*)
>> z = t(3,*)
>>
>> p = PLOT3D(x, y, z,'o')
>
>
> I have found that function graphics are particularly picky about
> whether you pass them a column vector or row vector. Problems arise when
> you pass data in as a row vector (a 1xN array, as you are doing above).
> The solution is to reform your data into a column vector (Nx1 array),
> like so
>
> x = reform(t[1,*])
> y = reform(t[2,*])
> z = reform(t[3,*])
>
> p = plot3d(x, y, z, 'o')
Matthew's suggestion is a good one, but being the memory-layout-worrier
that I am (preferring t[*,0] over t[0,*]), I would simply transpose the
"t" array directly after reading it in from wherever it was created,
The original data...
IDL> t = findgen(5,200)
IDL> help, t
T FLOAT = Array[5, 200]
IDL> print, t[0,*]
0.00000
5.00000
10.0000
15.0000
20.0000
25.0000
30.0000
35.0000
40.0000
45.0000
.....
Transpose it for all subsequent use:
IDL> t = transpose(t)
IDL> help, t
T FLOAT = Array[200, 5]
IDL> print, t[*,0]
0.00000 5.00000 10.0000 15.0000 20.0000
25.0000 30.0000 35.0000 40.0000 45.0000
....
When the trailing dimension is the degenerate one, IDL happily ignores
it....
IDL> x = COS(t) * (1 + t / 10)
IDL> help, x
X FLOAT = Array[200, 5]
IDL> p = PLOT3D(x[*,0], x[*,1], x[*,2],'o')
cheers,
paulv
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| Re: PLOT3D format input [message #90643 is a reply to message #90626] |
Thu, 19 March 2015 16:24 |
lucesmm
Messages: 26
Registered: October 2014
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Junior Member |
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On Wednesday, March 18, 2015 at 12:38:53 PM UTC-7, Paul van Delst wrote:
> Hello,
>
> On 03/17/15 22:49, Matthew Argall wrote:
>>> t=FINDGEN(5,200)
>>> x = t(1,*)
>>> y = t(2,*)
>>> z = t(3,*)
>>>
>>> p = PLOT3D(x, y, z,'o')
>>
>>
>> I have found that function graphics are particularly picky about
>> whether you pass them a column vector or row vector. Problems arise when
>> you pass data in as a row vector (a 1xN array, as you are doing above).
>> The solution is to reform your data into a column vector (Nx1 array),
>> like so
>>
>> x = reform(t[1,*])
>> y = reform(t[2,*])
>> z = reform(t[3,*])
>>
>> p = plot3d(x, y, z, 'o')
>
> Matthew's suggestion is a good one, but being the memory-layout-worrier
> that I am (preferring t[*,0] over t[0,*]), I would simply transpose the
> "t" array directly after reading it in from wherever it was created,
>
> The original data...
>
> IDL> t = findgen(5,200)
> IDL> help, t
> T FLOAT = Array[5, 200]
> IDL> print, t[0,*]
> 0.00000
> 5.00000
> 10.0000
> 15.0000
> 20.0000
> 25.0000
> 30.0000
> 35.0000
> 40.0000
> 45.0000
> .....
>
> Transpose it for all subsequent use:
>
> IDL> t = transpose(t)
> IDL> help, t
> T FLOAT = Array[200, 5]
> IDL> print, t[*,0]
> 0.00000 5.00000 10.0000 15.0000 20.0000
> 25.0000 30.0000 35.0000 40.0000 45.0000
> ....
>
> When the trailing dimension is the degenerate one, IDL happily ignores
> it....
>
> IDL> x = COS(t) * (1 + t / 10)
> IDL> help, x
> X FLOAT = Array[200, 5]
> IDL> p = PLOT3D(x[*,0], x[*,1], x[*,2],'o')
>
>
> cheers,
>
> paulv
Thank you
Now I can plot it.
Sometimes I don't understand how this formatting works...
-LMM
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