| Plotting a horizontal line over a cgImage [message #93582] |
Mon, 29 August 2016 09:03  |
Christina Haig
Messages: 4
Registered: August 2016
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Junior Member |
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This question probably has a very specific audience, but anyone who might be able to help me I would greatly appreciate.
Here is a good example of a cgimage plot, somewhat complex, but nothing untoward:
p = pos[*,0]
cgimage,data1,/DEVICE,/SCALE,/AXES,position=[p[0],p[1],p[2], p[3]],$
xrange=[mint,maxt],yrange=[minp,maxp],charsize=3,$
AXKEYWORDS={xtickformat:'(A1)',ylog:1,yticks:2,$
ytickname:['10!e0','10!e1','10!e2']},/noerase
As you can see, the yrange goes roughly from 1 to 100ish. I would like to plot a horizontal line at 2 that references the axes set in the cgimage command, and at the position of the same (there are 12 total plots in my output). Now oplot obviously does not allow the position command. So I attempted to cleverly use the cgplot command to overplot the line.
cgplot,[mint,maxt],[2.0,2.0],thick=4,line=5,color=255,$
position=[p[0],p[1],p[2],p[3]],/overplot
However nothing shows up in my plot. Can anyone advise me how I might solve this problem?
Thanks,
Christina
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| Re: Plotting a horizontal line over a cgImage [message #93583 is a reply to message #93582] |
Mon, 29 August 2016 11:20  |
wlandsman
Messages: 743
Registered: June 2000
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Senior Member |
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On Monday, August 29, 2016 at 12:03:11 PM UTC-4, Christina Haig wrote:
> As you can see, the yrange goes roughly from 1 to 100ish.
Actually we can't see ;-) We (the readers of this newsgroup) don't know the content of your variables, and we can't see the output plot.
But your code looks like it should work. Does the CGPLOT command come immediately after the CGIMAGE command or is there something in between that could reset the positioning?
Also I would set COLOR='green' (or something similar) in your CGPLOT command, in case there is something funky with the color table.
Also check the coordinate transformation between data and device coordinates
IDL> print,convert_coord(mint,maxt],[2.0,2.0],/data,/to_device)
to make sure the line is in the physical area of the window. --Wayne
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| Re: Plotting a horizontal line over a cgImage [message #93584 is a reply to message #93582] |
Mon, 29 August 2016 11:20 |
Christina Haig
Messages: 4
Registered: August 2016
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Junior Member |
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One edit to say I changed to:
cgplot,[mint,maxt],[2.0,2.0],thick=4,line=5,color=255,$
position=[p[0],p[1],p[2],p[3]],/ylog,/overplot
However, still nothing.
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| Re: Plotting a horizontal line over a cgImage [message #93585 is a reply to message #93583] |
Mon, 29 August 2016 12:29 |
Christina Haig
Messages: 4
Registered: August 2016
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Junior Member |
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On Monday, August 29, 2016 at 2:20:04 PM UTC-4, wlandsman wrote:
> On Monday, August 29, 2016 at 12:03:11 PM UTC-4, Christina Haig wrote:
>
>> As you can see, the yrange goes roughly from 1 to 100ish.
>
> Actually we can't see ;-) We (the readers of this newsgroup) don't know the content of your variables, and we can't see the output plot.
>
> But your code looks like it should work. Does the CGPLOT command come immediately after the CGIMAGE command or is there something in between that could reset the positioning?
>
> Also I would set COLOR='green' (or something similar) in your CGPLOT command, in case there is something funky with the color table.
>
> Also check the coordinate transformation between data and device coordinates
>
> IDL> print,convert_coord(mint,maxt],[2.0,2.0],/data,/to_device)
>
> to make sure the line is in the physical area of the window. --Wayne
Hi Wayne, thanks for your reply. I decided to try your suggestion of 'green', and also 'black', just in case. Also, my color table goes from black to white (255 to 0), and I tried both of those.
I also tried the convert_coord command, but /to_device gives some weirdly large numbers that I don't quite understand. I then tried convert_coord with /to_normal and got:
0.088541664 0.95833331 0.0000000
0.35069446 0.95833331 0.0000000
This looks like it should be somewhere in the plot area, in the general region of the upper-lefthand-corner where the underlying plot is. There is nothing between the cgplot and cgimage command. Is there something about either cgplot or cgimage that doesn't like one writing over the other perhaps? Is there a way to override this?
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| Re: Plotting a horizontal line over a cgImage [message #93588 is a reply to message #93585] |
Tue, 30 August 2016 06:59 |
wlandsman
Messages: 743
Registered: June 2000
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Senior Member |
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I had tested your code by putting in fake data below and I see the horizontal line at y=2. --Wayne
cgimage,dist(512),/DEVICE,/SCALE,/AXES,position=[0.2,0.2,0.9 ,0.9],$
xrange=[1,10],yrange=[1,100],charsize=3,$
AXKEYWORDS={xtickformat:'(A1)',ylog:1,yticks:2,$
ytickname:['10!e0','10!e1','10!e2']},/noerase
cgplot,[1,10],[2.0,2.0],thick=4,line=5,color='green',$
position=[0.2,0.2,0.9,0.9],/overplot
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| Re: Plotting a horizontal line over a cgImage [message #93654 is a reply to message #93582] |
Thu, 22 September 2016 14:08 |
Jeremy Bailin
Messages: 618
Registered: April 2008
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Senior Member |
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On Monday, August 29, 2016 at 11:03:11 AM UTC-5, Christina Haig wrote:
> This question probably has a very specific audience, but anyone who might be able to help me I would greatly appreciate.
>
> Here is a good example of a cgimage plot, somewhat complex, but nothing untoward:
>
> p = pos[*,0]
> cgimage,data1,/DEVICE,/SCALE,/AXES,position=[p[0],p[1],p[2], p[3]],$
> xrange=[mint,maxt],yrange=[minp,maxp],charsize=3,$
> AXKEYWORDS={xtickformat:'(A1)',ylog:1,yticks:2,$
> ytickname:['10!e0','10!e1','10!e2']},/noerase
>
> As you can see, the yrange goes roughly from 1 to 100ish. I would like to plot a horizontal line at 2 that references the axes set in the cgimage command, and at the position of the same (there are 12 total plots in my output). Now oplot obviously does not allow the position command. So I attempted to cleverly use the cgplot command to overplot the line.
>
> cgplot,[mint,maxt],[2.0,2.0],thick=4,line=5,color=255,$
> position=[p[0],p[1],p[2],p[3]],/overplot
>
> However nothing shows up in my plot. Can anyone advise me how I might solve this problem?
>
> Thanks,
> Christina
Are minp and maxp what you think they are?
-Jeremy.
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| Re: Plotting a horizontal line over a cgImage [message #93659 is a reply to message #93654] |
Fri, 23 September 2016 12:04 |
Christina Haig
Messages: 4
Registered: August 2016
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Junior Member |
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On Thursday, September 22, 2016 at 5:08:47 PM UTC-4, Jeremy Bailin wrote:
> On Monday, August 29, 2016 at 11:03:11 AM UTC-5, Christina Haig wrote:
>> This question probably has a very specific audience, but anyone who might be able to help me I would greatly appreciate.
>>
>> Here is a good example of a cgimage plot, somewhat complex, but nothing untoward:
>>
>> p = pos[*,0]
>> cgimage,data1,/DEVICE,/SCALE,/AXES,position=[p[0],p[1],p[2], p[3]],$
>> xrange=[mint,maxt],yrange=[minp,maxp],charsize=3,$
>> AXKEYWORDS={xtickformat:'(A1)',ylog:1,yticks:2,$
>> ytickname:['10!e0','10!e1','10!e2']},/noerase
>>
>> As you can see, the yrange goes roughly from 1 to 100ish. I would like to plot a horizontal line at 2 that references the axes set in the cgimage command, and at the position of the same (there are 12 total plots in my output). Now oplot obviously does not allow the position command. So I attempted to cleverly use the cgplot command to overplot the line.
>>
>> cgplot,[mint,maxt],[2.0,2.0],thick=4,line=5,color=255,$
>> position=[p[0],p[1],p[2],p[3]],/overplot
>>
>> However nothing shows up in my plot. Can anyone advise me how I might solve this problem?
>>
>> Thanks,
>> Christina
>
> Are minp and maxp what you think they are?
>
> -Jeremy.
Apologies for the delay in replying. This was in fact the problem. The problem was my data was already logarithmic, and thus my axes were 0 - 2.0. My fault for not remembering that /ylog just changes the tick names of the axes on cgplot, but the min and max has to be already logged.
So what I needed was to put in log(2.0), instead of just 2.0. I'll leave this thread up in case other people have trouble with logarithmic cgplot.
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