On 7/29/2011 1:21 AM, Alexander Klenin wrote:
Please, do not top-post. It makes it very hard to read and reply to
your messages.
On Fri, Jul 29, 2011 at 15:56, David M. Lawrence<[email protected]> wrote:
No, they happened when I tried to plot the chart. I couldn't figure out how
to implement the auto-scaling transformation from the demo. For example, I
see catTAuto listed as a transformation in the object inspector and listed
as a property in the axisdemo main.pas, but cannot find any code to
implement it there. I do see it mentioned in main.lfm, but don't understand
how it works -- it seems to list properties for the transform more than
anything else.
There is no code -- just setting correct properties is enough.
In any event, for consistency's sake I need to maintain axes of -90 C to 60
C for the temperature axis, and 0 cm to 300 cm for the precipitation axis.
Since I plot up to three temperature series, it's easier to set that as
fixed and figure out how to transform the precipitation axis.
You seem to have a lot invested in the idea that flexible transformations
are best from a coding standpoint, but the hundreds of charts I plot have to
be plotted consistently -- there can be no individualized scaling. The bars
on a graph from a site with a maximum monthly precipitation of 20 cm need to
be one-tenth as tall as the bars from a site with maximum monthly
precipitation of 200 cm. I am not just comparing the bars and lines on an
individual chart, I am comparing one chart to similar charts from hundreds
of sites around the world. That way I and others can tell the chart from a
desert site, for example, from that of a tropical rainforest site or monsoon
forest site. From that standpoint, being able to independently set max and
min values for each vertical axis would be a lot better.
I see now -- so you actually do NOT want auto-scale, but a fixed scale.
In this case, simply use linear transformation and then Chart.Extent property.
You will have to calculate scale and offset yourself (once, at design-time).
(From my quick calculation, you should use scale=0.5 and offset=-90,
but check yourself)
I'll check the linear transform. Those values are what I was thinking
they should be. I'll give them a shot.
Note, however, that if by chance your data will be outside of the
designated extent,
it will be cut off.
I can see your point for axis min/max values, so maybe I implement them.
However, how should they behave in the case of out-of-bounds data points
I described above?
Out-of-bounds data points would be clipped. In my case, I determined my
max/min limits empirically by scanning global temperature and
precipitation records. There should be no out-of-bounds points -- on
Earth, anyway. If climate conditions do affect extremes, I wrote batch
procedures that allow me to redraw all the charts in my database with
new maximum and minimum values in a matter of minutes.
Thanks again,
Dave
P.S. Does this list allow attachments?
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David M. Lawrence | Home: (804) 559-9786
7471 Brook Way Court | Fax: (804) 559-9787
Mechanicsville, VA 23111 | Email: [email protected]
USA | http: http://fuzzo.com
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"We have met the enemy and he is us." -- Pogo
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