Function graphics /OVERPLOT redefines axis limits after plot with/NODATA

Hello,

I've just "discovered" this weirdness:

IDL> x=plot(lindgen(100)-50,/nodata)
IDL> xi=plot(x.xrange,[0,0],linestyle='dash',/overplot)

On my system, the second command with the /OVERPLOT redefines the yrange of the resulting plot.

The documentation of PLOT, /NODATA states:
"Set this property to 1 to create the graphic, but without any data attached to it. The axes and title (if present) are
also created and displayed."

The documentation of PLOT, /OVERPLOT states:
"Set this property to 1 (one) to place the graphic on top of the existing graphic in the current window."

Now the /NODATA docs state there is no data attached to the plot... but there is some data/information attached to it
since the axis limits are defined and displayed correctly when the plot is initially created.

Note that if the initial /NODATA is not used,

IDL> x=plot(lindgen(100)-50)
IDL> xi=plot(x.xrange,[0,0],linestyle='dash',/overplot)

everything behaves as expected.

In what universe does /OVERPLOT mean:
/ONLY_OVERPLOT_DEPENDING_ON_HOW_THE_EXISTING_GRAPHI C_WAS_CREATED_OTHERWISE_REDEFINE_AXIS_LIMITS.

My IDL:
IDL> print, !version
{ x86 linux unix linux 8.1 Mar 9 2011 32 64}

Sigh. Anyone know if this has been fixed in v8.2?[*]


not-so-cheerily yours,

paulv

[*] With my luck it will have been fixed, but the undocumented /HISTOGRAM keyword to PLOT() will also have been removed
(see my thread from yesterday)

On Tuesday, July 3, 2012 11:33:01 AM UTC-4, Paul van Delst wrote:

> Sigh. Anyone know if this has been fixed in v8.2?[*]
>

Yes, it is fixed in V8.2. In V8.1 you can use the following workaround

IDL> x=plot(lindgen(100)-50)
IDL> xi=plot(x.xrange,[0,0],linestyle='dash',/overplot,yrange=x.yrange)

-- Wayne

Hi Wayne,

Thanks for the info. I've requested an upgrade.

I did finally come upon the workaround... it just took a while.

cheers,

paulv

On 07/03/12 22:25, wlandsman wrote:
> On Tuesday, July 3, 2012 11:33:01 AM UTC-4, Paul van Delst wrote:
>
>> Sigh. Anyone know if this has been fixed in v8.2?[*]
>>
>
> Yes, it is fixed in V8.2. In V8.1 you can use the following workaround
>
> IDL> x=plot(lindgen(100)-50)
> IDL> xi=plot(x.xrange,[0,0],linestyle='dash',/overplot,yrange=x.yrange)
>
> -- Wayne

On 7/3/12 9:25 PM, wlandsman wrote:
> On Tuesday, July 3, 2012 11:33:01 AM UTC-4, Paul van Delst wrote:
>
>> Sigh. Anyone know if this has been fixed in v8.2?[*]
>>
>
> Yes, it is fixed in V8.2. In V8.1 you can use the following workaround
>

I don't think it is fixed. I observe the same weirdness in this system:

IDL> print,!version
{ x86_64 darwin unix Mac OS X 8.2 Apr 10 2012 64 64}

But the workaround for 8.1 also works for 8.2.

-Caesar

On Thursday, July 5, 2012 5:11:21 PM UTC-4, nerdzoo wrote:
> On 7/3/12 9:25 PM, wlandsman wrote:

> > Yes, it is fixed in V8.2. In V8.1 you can use the following workaround
> >
>
> I don't think it is fixed. I observe the same weirdness in this system:
>
Yeah, I withdraw my statement that the /overplot problem is fixed in V8.2. I must have neglected the /nodata keyword in my quick test. --Wayne