Re: Interesting IDLgrContour Bug

[Harold Cline <hjcline(at)home.com>]

Hi David,

Did you report this to tech support yet?

Cheers,
Harold Cline
RSI
home:hjcline@home.com
work:harold@rsinc.com

David Fanning wrote:
> 
> Hi Folks,
> 
> I ran into an interesting little IDLgrContour bug today
> that gave me a few hours of fun. Apparently, the
> contour algorithm cannot see positive data that is less
> than 1. As a result, it reports the contour range incorrectly.
> Here is a very short example:
> 
>       ; Create test data.
>    data = Dist(40)
> 
>       ; Normalize the Y values from 20 to 39 to be less than 0.
>    data[*,20:39] = data[*,20:39]/Max(data)
> 
>       ; Create contour plot.
>    x = findgen(40)
>    y = findgen(40)
>    theContour = Obj_New('IDLgrContour', data, Geomx=x, Geomy=y)
> 
>       ; Get the Y range of the data.
>    theContour->GetProperty, YRange=theBadRange
> 
>       ; Print it. Expect 0 to 39.
> 
>    Print, theBadRange
>       0.000000      19.8495
> 
> Whoops! Of course, this will cause the scaling to be
> completely off when you go to put the plot into your
> view.
> 
> The work around is to get the contour range from
> the X and Y vectors. I don't think too many people
> will run into this, but it can be distracting. :-)
> 
> I've tested this in IDL 5.3.1 and IDL 5.4 beta on
> Windows NT 4.0.
> 
> Cheers,
> 
> David
> --
> David Fanning, Ph.D.
> Fanning Software Consulting
> Phone: 970-221-0438 E-Mail: davidf@dfanning.com
> Coyote's Guide to IDL Programming: http://www.dfanning.com/
> Toll-Free IDL Book Orders: 1-888-461-0155