From: martinl_at_talk21.com
Date: Thu Jan 18 2001 - 14:17:30 CET
Received: (from mdom_at_localhost) by karto.ethz.ch (8.9.3/8.9.3/SuSE Linux 8.9.3-0.1) id OAA10413 for cavexml-outgoing; Thu, 18 Jan 2001 14:17:30 +0100 Received: from t21mta03-app.talk21.com (mta03.talk21.com [62.172.192.172]) by karto.ethz.ch (8.9.3/8.9.3/SuSE Linux 8.9.3-0.1) with ESMTP id OAA10409 for <cavexml_at_cartography.ch>; Thu, 18 Jan 2001 14:17:29 +0100 From: martinl_at_talk21.com Received: from t21mtaV-lrs ([10.216.84.19]) by t21mta03-app.talk21.com (InterMail vM.4.01.02.27 201-229-119-110) with SMTP id <20010118131841.JQLT2134.t21mta03-app.talk21.com_at_t21mtaV-lrs> for <cavexml_at_cartography.ch>; Thu, 18 Jan 2001 13:18:41 +0000 X-Mailer: talk21 v1.15 - http://www.talk21.com To: cavexml_at_cartography.ch X-Talk21Ref: none Date: Thu, 18 Jan 2001 13:14:55 GMT+00:00 Subject: crossSections Content-type: text/plain; charset="ISO-8859-1" Message-Id: <20010118131841.JQLT2134.t21mta03-app.talk21.com@t21mtaV-lrs> Content-Transfer-Encoding: 8bit X-MIME-Autoconverted: from quoted-printable to 8bit by karto.ethz.ch id OAA10410 Sender: owner-cavexml_at_karto.baug.ethz.ch Precedence: bulk
I'ld agree that LRUD (and/or LRCF) be allowed for importing old data but be deprecated in favour of a crossSection element or attribute. Also, cross section should only be fixed to station as a special case.
As one potential use of survey data is in creating 3D models, I'ld suggest that people look at the VRML Extrusion node (explained at http://www.best.com/%7Erikk/Book/ch3-318.htm),
or its X3D descendant defined in XML as:
<Shape DEF='SHAPE_EXTRUSION'>
<Extrusion
DEF='EXTRUSION'
scale=' 1.0 1.0'
crossSection=' 1.0 1.0, 1.0 -1.0, -1.0 -1.0, -1.0 1.0, 1.0 1.0'
spine=' 0.0 0.0 0.0, 0.0 1.0 0.0'/>
<Appearance USE='APPEARANCE'/>
</Shape>
(see http://www.web3d.org/TaskGroups/x3d/translation/examples/development/_pages/page01.html)
as a starting point.
The 'crossSection' definition is similar to Julian's.
The 'scale' might be useful so we could reference standard cross sections - tube; keyhole; rift; fig8; etc).
The 'spine' is our 'leg'/'shot'
The VRML 'orientation' is like yaw, roll, tilt. The rather unfrienly VRML xFRotation (x y z r) where x,y,z define an axis and r a rotation about it may be better substituted by a ref to the leg along which the section occurs (or its projection).
Julian's 'lambda' represents the distance along a leg; I'ld replace 'lambda' by something less mathsy like 'distance' (distance="0" would be at the 'from' station, distance=leg length would be at 'to' station; negative distance would be behind from the 'from' station ...). I think Tunnel also allows for a couple of angles, where I'ld suggest more familiar terminology for cavers might be dip and strike...
...
In practice this will be a lot easier to use than it is to explain! For example, it would look like this for a triangular passage 2 units high and wide:
<leg from="1" to="2" dist="1.2" bear="34" incl="5" >
<crossSection points="-1 -1, 0 2, 1 -1" distance=".6" />
</leg>
Using a definition and xlink structure as in SVG (Scalable Vector Graphics) we might have something like:
<def name="tri" crossSection="-1 -1, 0 2, 1 -1" />
...
<leg from="3" to="2" dist="6.7" bear="89" incl="-30"
comment="now the passage is twice as wide, but no higher">
<crossSection crossSection="xlink:#tri" scale="2 1" dip ="60"
comment="the cross section is made vertical by specifying dip
- default would be perpendicular to leg" />
</leg>
========================================================
more XML,XSLT,SVG,VRML,X3D examples, thoughts, links at:
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