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phensel
USA
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 Posted - 08/12/2005 : 4:47:46 PM
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Origin Version (Select Help-->About Origin): 7.5
Operating System: Windws XP Professional
Newbie to the list here - Anyone have problems with the scaling of the Y-axis on a vector plot? The vector length is supposed to be related to the scaling of the Y-axis, no? It seems that the Y-axis is totally arbitrary: only _occasionally_ can I get correspondence, and then only when I use the "magnitude multiplier" of 10.
Sorry, my IT guys only got me the software, not the manual, and the "help" utility is very lame. = (
What's the secret with the axis scaling on the vector plot?
Thanks & Cheers,
-Philippe
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easwar
USA
1964 Posts |
Posted - 08/12/2005 : 5:13:11 PM
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Hi Philippe,
There are two vector plot types XYXY and XYAM. For the first one the beginning and end x,y points are specified and for the second one, the begging x,y point and the angle and magnitude of the vector are specified.
Looks like what you are using is the XYAM plot. With this plot, one point to note, which we need to clarify in our documentation, is that the angular unit used is specified in the dialog brought up by the Tools->Options... menu command and then the Numeric tab and the Angluar units group.
The default setting is radian and so your angular data is interpreted as radian. So if you in fact have numbers that correspond to degrees, then the plot will not "look right". You will then need to change the angular units (don't have to save the settings as default), close the dialog and then refersh the graph.
I suspect this is the problem? If not, please send your Origin Project file (.OPJ) to tech@orignilab.com and please refer to this post.
Easwar
OriginLab
Edited by - easwar on 08/12/2005 5:13:29 PM |
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thuang
USA
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Posted - 10/20/2005 : 4:59:50 PM
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yes i have the same problem with XYAM. i think what he means is that the length of the vector is very strange. for example, if i made a vector starting at 0, 0 the origin, with an angle of 0 and length of 1, the length shown on the graph looks more like .001 or some very small number. then when i zoom in or rescale the axis to look at it since it's so small, the size of the line does not change at all.
next, i try using the multipy by factor thing in the vector tab, it makes the length bigger, but zooming and scaling still don't do anything afterwards.
the angular thing was a problem too. i went to labtalk and used system.math.AngularUnits=1; to change angular units to degrees but that wasn't such a big problem.
so if anyone knows why the vector lengths in the XYAM plot comes out so small and why they do not change when the axis is rescaled, please help us? thanks |
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easwar
USA
1964 Posts |
Posted - 10/20/2005 : 5:21:42 PM
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Hi thuang,
User Philippe did contact tech support directly and we answered - we did not update this thread - our apologies.
If you look in the help documentation for XYAM plot, you will find the following note:
"The leftmost Y column controls the Y coordinate of the vector tail (by default). The second Y column determines the angle of the vector. The angle is measured counterclockwise from a line parallel to the X axis, bisecting the vector. The third Y column controls the vector length in units of points. The Plot Details dialog box provides a control to scale the length of the vector (Format:Plot)."
So the Magnitude number in the fourth column is interpreted in units of points and is not related to either the x or y scale. The units of points refers to the the printer's unit of measurement, which is typically 1/72 of an inch. Also notice that you can arbitrarily sale this length using plot details dialog, and thus could for example enter a value of 72 in which case each unit will represent 1 inch on the graph. We will consider adding more options to this control in a future version.
Easwar
OriginLab
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easwar
USA
1964 Posts |
Posted - 10/21/2005 : 11:45:38 AM
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Hi thuang,
Just wanted to point that one possible workaround to this problem is to convert your XYAM data to XYXY. Since you know the angular units and the scale of your M column, you can compute the end point XY values and with the starting and end values, you can make the plot using XYXY vector instead of XYAM vector.
Easwar
OriginLab
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thuang
USA
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Posted - 10/21/2005 : 7:57:10 PM
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oh, it's in pixels/inches. well, ok i guess i will try using XYXY after converting the vector head from AM to X2Y2.
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Y axis scaling problem on Vector Graph