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List:       postgis-users
Subject:    Re: [postgis-users] Ideas for 3D snapping for linestrings
From:       Alexandre Neto <senhor.neto () gmail ! com>
Date:       2020-08-12 15:24:25
Message-ID: CA+H0G_G1fRZ9yAoXvLj1_3ewWhkC467R_vBDnj3Q5+XyGp_wgQ () mail ! gmail ! com
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Never mind,

It seems that, despite not saying in the documentation, ST_SNAP will also
snap vertexes to the Z value of the reference feature. The only thing that
is not taken into consideration is the 3D distance for the tolerance, which
seems to be planimetric.

Thanks

Alexandre Neto

On Wed, Aug 12, 2020 at 2:42 AM Alexandre Neto <senhor.neto@gmail.com>
wrote:

> Hi,
>
> In the past I have successfully been able to fix linestring topology
> problems (undershoots and overshoots) by using the following approach:
>
> - identify startpoints and endpoints closer to another line less than a
> given distance;
> - determine the closest point to that other line;
> - use a collection of closest points as input to ST_snap, to force the
> lines to pass on those points.
>
> This works fine for 2D linestrings, but know I need to make the Z values
> of those touching vertexes also match. If I am not wrong, ST_snap only
> works for 2D, Any ideas of how to assign the same Z to vertexes that have
> the same XY?
>
> Thanks,
>
> Alexandre Neto
>
> Now, I also need to do it in 3D, any
>

[Attachment #5 (text/html)]

<div dir="ltr">Never mind,<div><br></div><div>It seems that, despite not saying in \
the documentation, ST_SNAP will also snap vertexes to the Z value of the reference \
feature. The only thing that is not taken into consideration is the 3D distance for \
the tolerance, which seems to be \
planimetric.</div><div><br></div><div>Thanks</div><div><br></div><div>Alexandre Neto  \
</div></div><br><div class="gmail_quote"><div dir="ltr" class="gmail_attr">On Wed, \
Aug 12, 2020 at 2:42 AM Alexandre Neto &lt;<a \
href="mailto:senhor.neto@gmail.com">senhor.neto@gmail.com</a>&gt; \
wrote:<br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px \
0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"><div \
dir="auto">Hi,<div dir="auto"><br></div><div dir="auto">In the past I have \
successfully been able to fix linestring topology problems (undershoots and \
overshoots) by using the following approach:</div><div dir="auto"><br></div><div \
dir="auto">- identify startpoints and endpoints closer to another line less than a \
given distance;</div><div dir="auto">- determine the closest point to that other \
line;</div><div dir="auto">- use a collection of closest points as input to ST_snap, \
to force the lines to pass on those points.</div><div dir="auto"><br></div><div \
dir="auto">This works fine for 2D linestrings, but know I need to make the Z values \
of those touching vertexes also match. If I am not wrong, ST_snap only works for 2D, \
Any ideas of how to assign the same Z to vertexes that have the same XY?</div><div \
dir="auto"><br></div><div dir="auto">Thanks,</div><div dir="auto"><br></div><div \
dir="auto">Alexandre Neto</div><div dir="auto"><br></div><div dir="auto">Now, I also \
need to do it in 3D, any</div></div> </blockquote></div>


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