[Qgis-user] defining a variable width vector style

[Tom Lennon]

Hi Robin:
I just noticed in the documentation for 2.16  at:

http://qgis.org/fr/site/forusers/visualchangelog216/index.html#feature-aggregate-support-for-expressions

Under: Feature: Arrow Symbol Layer

It appears that you can make arrows with tapered shafts.
The shafts hasve start and end width settings and the heads could be set
small.
The shafts can also follow curved lines.
Haven't tried it yet
Good luck
Tom

On Fri, Aug 12, 2016 at 8:16 PM, Robin Paulson <robin at bumblepuppy.org>
wrote:

> hi folks,
> i'm trying to define a style which varies along the length of the line
> it's applied to, according to the position along that line. at the moment,
> as far as i can see, all styles are continuous along the line
>
> so, for example let's say i want the line to be drawn as a cone, i would
> define the width of the style as proportional to the position on the line.
>
> something like: line_width = line_pos x 0.1
>
> at the start of the line, the width of the style should be 0m
> 1m along the line, the width should be 0.1m
> 1.5m along the line, the width should be 0.15m
> 10m along the line, the width should be 1m
> and so on
>
> any ideas about the best way to do this?
>
> i considered adding a *lot* of nodes and varying the width in small steps
> at each node, but that would be clumsy and fiddly.
>
> cheers,
>
> --
> robin
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-- 
tolennon at gmail.com
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