John Hunter wrote:
“Paul” == Paul Barrett <pebarrett@…149…> writes:
> I have data that has error bars and upper limits. (Actually
> they are lower limits, since the Y axis is in stellar
> magnitudes and is inverted.) My suggestion is use a negative
> error value to indicate a limit in which case an arrow would
> be drawn, instead of an error bar. This feature would only
> apply to the case of asymmetric error bars and not to the
> symmetric case. I can produce a patch if this suggestion is
I certainly don’t have a problem with this and would be happy to
include these extensions to the errorbar function. I wonder if the
arrow is the best indicator for a limit, though I can’t think of a
better one at the moment. Also, does this handle limits in either
direction (up or down) as well as left to right?
Arrows are often used to indicate error bars which end outside of the
displayed area of the plot. I would also recommend against using
negative error values to indicate limits instead of errors. It smells of
Yes, it does smell of FORTRAN. However, my motive for suggesting
negative error values is that it allows the user to specify the length
of the limit arrow and numeric arrays to be used for input. The other
option would be to use a string, e.g.‘limit(2)’, as a marker.
This will complicate the implementation, but that is less of a concern
to me than usability. I think that the ability to specify the
length of the arrow is needed. This could be an optional
parameter though. I’m open to suggestions.
Limits should probably be implemented by a separate
In astronomy, limit data is often associated with data having large
error bars, i.e. they go hand-in-hand. So, a separate function would
essentially duplicate the error bar functionality. I see no
need for this duplicity.
On 10/7/05, Robert Kern <rkern@…170…> wrote: