[mapserver-users] Orientation of vector symbols on a LINE

TC Haddad tchaddad at gmail.com
Thu Aug 29 07:57:50 PDT 2013


Thanks Havard, for the pointer to the answer and explanation of the ratio
between SIZE and GAP. I feel like I will use that a lot.

Thanks Thomas for your clarification - my misunderstanding was regarding
the negative values, I hadn't fully  internalized that y=0 was the top of
the symbol.

Tanya


On Thu, Aug 29, 2013 at 12:24 AM, thomas bonfort
<thomas.bonfort at gmail.com>wrote:

> Given that there's alot of undefined behavior with vector symbols, the
> documentation for anchorpoint is pretty clear about what is supported:
> <quote>
> ANCHORPOINT can be used with SYMBOLs of TYPE ellipse, pixmap, svg,
> truetype and vector. To ensure proper behaviour for vector symbols,
> the left and top edges of the bounding box of the symbol should be at
> 0.
> </quote>
> As a rule of thumb, VECTOR symbols are expected to work correctly if
> they respect that rule, i.e. your vector POINTS should have at least
> one point with x=0, at least one point with y=0, and no negative x's
> or y's.
>
> --
> thomas
>
> On 29 August 2013 09:05, Havard Tveite <havard.tveite at umb.no> wrote:
> > The implementation of GAP has been fixed (center to center
> > distance between symbols), and so has the calculation of
> > symbol height.
> > I guess that the following should work:
> >
> >
> > STYLE
> >   SYMBOL "wavy_line"
> >   WIDTH 1
> >   SIZE 2
> >   GAP -6
> >
> >   COLOR 0 0 0
> > END
> >
> > Since you have y values from -1 to 1, and x values between 0
> > and 6, the ratio between the height of your symbol and the
> > length is 2 / 6.  The ratio between size and gap should be the
> > same to make the the line continuous.
> >
> > Håvard
> >
> >
> > On 8/29/2013 1:31 AM, TC Haddad wrote:
> >>
> >>
> >> Hello, I'm trying to understand symbol orientation and (maybe) use of
> >> ANCHORPOINT on a line in Mapserver 6.2.
> >>
> >> The vector symbol that I have been using for line cartography in
> MapServer
> >> 6.0.3 is below, and I am trying to get the same effect in Mapserver
> 6.2.1.
> >>
> >> SYMBOL
> >>    NAME "wavy_line"
> >>    TYPE vector
> >>    POINTS
> >>      0 0
> >>      1 1
> >>      2 1
> >>      3 0
> >>      4 -1
> >>      5 -1
> >>      6 0
> >>    END
> >> END
> >>
> >> Display in Mapserver 6.0.3:
> >> https://dl.dropboxusercontent.com/u/42845001/mapserver6.0.3.png
> >>
> >> Relevant Style bloc from Mapserver 6.0.3:
> >>
> >> STYLE
> >>       SYMBOL "wavy_line"
> >>       WIDTH 1
> >>       SIZE 2
> >>       GAP -1
> >>       COLOR 0 0 0
> >> END
> >>
> >> This did not translate directly to Mapserver 6.2.1, but I came close
> with
> >> this:
> >>
> >> STYLE
> >>      SYMBOL "wavy_line"
> >>       WIDTH 1
> >>       SIZE 4
> >>       GAP 6
> >>       COLOR 0 0 0
> >> END
> >>
> >> which produced this:
> >> https://dl.dropboxusercontent.com/u/42845001/mapserver6.2.1.png
> >>
> >> Obviously I am missing something about how to get the symbol to orient
> >> along the line, I played with ANCHORPOINT as that  was new in 6.2 and it
> >> seemed like the default of 0.5 0.5  should work for my symbol, but I
> also
> >> tried several other value combinations and it seemed to merely shift the
> >> symbol around laterally, while maintaining an upright orientation.
> >>
> >> So I'm a bit confused on how to achieve the original effect, (behavior
> >> something like the equivalent of FOLLOW for Labels). Any pointers
> >> appreciated...
> >>
> >>
> >> _______________________________________________
> >> mapserver-users mailing list
> >> mapserver-users at lists.osgeo.org
> >> http://lists.osgeo.org/mailman/listinfo/mapserver-users
> >>
> >
> > --
> > Håvard Tveite
> > Department of Mathematical Sciences and Technology, UMB
> > Drøbakveien 31, POBox 5003, N-1432 Ås, NORWAY
> > Phone: +47 64965483 Fax: +47 64965401 http://www.umb.no/imt/
> > _______________________________________________
> > mapserver-users mailing list
> > mapserver-users at lists.osgeo.org
> > http://lists.osgeo.org/mailman/listinfo/mapserver-users
> _______________________________________________
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>
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