Hi,
If a line-width with "0" is rendered than it is a rendering issue and
not a logical issue.
The CASE WHEN ELSE END statement always returns a value. That's what I
meant that it seems logical to me.
I don't think that QGIS does suppress the rendering of lines with zero
width. It just passes it on to the render with a line-width value of
zero. If the renderer still draws the line it is a bug in the renderer.
Of course could check if the line-width is zero and suppress the line.
But I don't know much about the renderer internals to know how QGIS is
handling it.
Andreas
Am 2013-11-19 13:16, schrieb Ziegler Stefan:
Hi Andreas
for me it seems unlogical. The CASE-WHEN-ELSE statement is returning
zero for scales larger than 1000. So I don't see any reason why QGIS
draws a line with an unpredictable line-width.
I do not have access at the very moment to QGIS. But what happens when
you just enter 0.0 as data defined line-width?
regards
Stefan
Von meinem iPad gesendet
Am 19.11.2013 um 11:59 schrieb "Andreas Neumann"
<[email protected]>:
Hi Stefan,
This seems logical to me. The data-defined styling only changes a
graphical property. It does not control whether a feature is drawn or
not. You could set it to fully transparent, but this would still fetch
features and draw them (though invisible).
If you want to suprress features above a certain level you may do that
on the layer level in the "General settings" (or something similar).
The labels individually allow to suppress labels based on a column or
expression, but the data-defined symbology does not allow that so far.
It would be a new feature to ask for.
Andreas
Am 2013-11-19 07:50, schrieb Ziegler Stefan:
Hi
I have a question regarding data defined styling. I'm using the
$scale
parameter to define the line width:
CASE
WHEN $scale <= 500.0 THEN 1
WHEN ($scale > 500 AND $scale <= 1000) THEN 0.5
END
I would expect that the line is not drawn with a scale larger than
1000. But it seems the line is still drawn. It even draws the line
with an ELSE-statement:
CASE
WHEN $scale <= 500.0 THEN 1
WHEN ($scale > 500 AND $scale <= 1000) THEN 0.5
ELSE 0.0
END
It seems that I get my expected result when I use an ELSE value near
zero (e.g. 0.0000001).
Is this on purpose? Or is there an error in my statement?
regards
Stefan
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