From: Ken Grimes (ken-grimes_at_h140.aone.net.au)
Date: Sat Jan 20 2001 - 04:13:10 CET
Received: (from mdom_at_localhost) by karto.ethz.ch (8.9.3/8.9.3/SuSE Linux 8.9.3-0.1) id EAA19117 for cavexml-outgoing; Sat, 20 Jan 2001 04:59:49 +0100 Received: from mta03.mail.mel.aone.net.au (mta03.mail.au.uu.net [203.2.192.83]) by karto.ethz.ch (8.9.3/8.9.3/SuSE Linux 8.9.3-0.1) with ESMTP id EAA19112 for <cavexml_at_cartography.ch>; Sat, 20 Jan 2001 04:59:47 +0100 Received: from ca121684 ([210.84.252.140]) by mta03.mail.mel.aone.net.au with SMTP id <20010120035950.BRNC19418.mta03.mail.mel.aone.net.au_at_ca121684> for <cavexml_at_cartography.ch>; Sat, 20 Jan 2001 14:59:50 +1100 Message-Id: <3.0.1.32.20010120141310.01a41a28@mail01.hml.aone.net.au> X-Sender: ca121684_at_mail01.hml.aone.net.au X-Mailer: Windows Eudora Light Version 3.0.1 (32) Date: Sat, 20 Jan 2001 14:13:10 +1100 To: <cavexml_at_cartography.ch> From: Ken Grimes <ken-grimes_at_h140.aone.net.au> Subject: Re: Cross Section libraries In-Reply-To: <021701c0822d$e9dba8c0$0a3c10ac_at_gordon> Content-Type: text/plain; charset="us-ascii" Sender: owner-cavexml_at_karto.baug.ethz.ch Precedence: bulk
>>> Try to think about something as "library of cross section" in detail
>>> defined somewhere in a file and use only reference to this library
>>> and actual proportions ("LRUD") to such profile in particular point.
>>>
>>> In real cave there are not endless kinds of profiles.
>>
Disagree strongly !!!
As a geomorphologist, the thought of a proscribed set of "standard"cross-sections is a can of worms. The possible variations are infinite!
One of the more usefull clues to a cave's evolution is a study of the details of wall shapes and cross-sections. Non-geological Cave mappers who assign a "standard" section "type" instead of sketching what is really there could confuse things badly.
Take the supposedly "typical" key-hole. The bottom trench can be narrow or broad, it can swing to either side, it may have a broadening at the base, or it may v-out. It may have subsidiary wall nitches (how many, which side?) .... and I havn't even started on the passage above the trench!
Who is going to define all these "types"? NOT me!
We have to remember that the ultimate objective of all this is to draw actual MAPS for peole to LOOK at - not to generate lots of computer files. The data files should always be accompanied by sketches of the details (scanned if needs-be, but it must be an true image not an over-simplified or 'standard' approximation!)
The auto-plotted & rendered computer views using LRUD etc are only usefull for SMALL-SCALE maps giving an overview of a whole cave. Now, this IS a usefull end (especially for large caves), but it needs little more than LRUD for the plot scales involved.
However, auto-rendered plots can never be used to show the fine details of wall-nitches, alcoves, bell-holes, spongework etc... and we should not pretend they can.
Sketching of wall detail (including sections) and contents is still the essential part of any cave mapping exercise - the numeric data is just a positional framework that we hang those details onto.
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SO:
I suggest that the XML data should stick to a simple LRUD set (for use in small-scale renderings), possibly with pointers from each segment of the survey to the locations of detailed sketches (wall shapes, roof profiles, cross-sections, and other details (stals, guano, water, scallops, ...)) which are held in separate (scanned?) files or paper-drawings.
The best way of getting the sketched details into a computer file is via CAD software (digitise the walls and sections etc, hand-place symbols for special features).
Having done that, perhaps it *might* be possible to write programs (specific to each CAD package!) to auto-generate an XML version of the CAD image ? But it would be tricky! How would the export software know that a particular curved-line-object is (eg) a roof profile referring to a passage elsewhere in the file? I suspect it would require a lot of human intervention to indicate the links (either during digitising - into a 3-D CAD file, or during export from a more conventional 2-D CAD file).
Most people would not have the time to do it.
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Ken Grimes Phone +61 +3 5573 4503
Regolith Mapping, PO Box 362, Hamilton, Vic 3300, Australia
Cainozoic Geology, Geomorphology, Karst & Speleology.
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