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MacLanD
Hong Kong
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 Posted - 07/08/2004 : 05:44:33 AM
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Hi,
I have a set of XYZ data, the XY are regular spaced, and there is no problem on plotting the contour.
But when after conterting the XY into the reciprocal space using Sine and Cosine function, not only the XY are irregularly spcaing,but also randomly sorting. The plot should look similar to the following image. The shape of the data point area is like a rhombus.
When I use "convert to matrix", it generate error. Is there a way to do the contour plot? Thanks.
Edited by - MacLanD on 07/08/2004 05:47:12 AM
Edited by - MacLanD on 07/08/2004 05:54:19 AM |
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easwar
USA
1964 Posts |
Posted - 07/08/2004 : 09:17:20 AM
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Hello,
What is the exact transformation equation that you are using? I see that your original x,y values go from -2 to 2, and -1 to 1 whereas your transfomred axes go from 4600 to 5100 and 5800 to 6100
Anyway, if you transform the x,y values of your regularly spaced xyz dataset with a nonlinear equation, this can result in an xyz dataset where the x and y are not regular anymore. Looks like this is the case. Then it is not possible to perform a regular conversion of the transformed data - you will need to use one of the random xyz gridding routines.
Easwar
OriginLab
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MacLanD
Hong Kong
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Posted - 07/08/2004 : 10:33:50 AM
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Thank you for your quick response.
The original XY shown in the attached graph is a relative value. The absolute value x=97.95 to 101.97430 y=9.88 to 11.86., they are all in degree.
The formula that I use for conversion is x'=[cos(y)-cos(x-y)]/c ,
y'=[sin(y)-sin(x-y)]/c. c is a constant.
The problem is when I use Edit->Convert to matrix->Random XYZ, it tells me "Error! Failed to sort and/or replace duplicates with mean value"
I don't know what is wrong.
Edited by - MacLanD on 07/08/2004 10:34:18 AM
Edited by - MacLanD on 07/08/2004 10:42:09 AM |
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easwar
USA
1964 Posts |
Posted - 07/08/2004 : 11:33:35 AM
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Hi,
Please send your data/OPJ to tech@originlab.com so that we can try your transformation/conversion to see the problem.
Please mention this forum post in your e-mail message.
Thanks,
Easwar
OriginLab
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MacLanD
Hong Kong
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Posted - 07/09/2004 : 03:07:12 AM
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Hi,
The data file has been sent to tech@originlab.com , please take a look at it. Thank you very much.
Macland |
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problem of contour plot for nonlinear xyz data