XML

[Michael Lake]

John Halleck wrote:
> Since there seems to be a request for the dialog to stay on the list,
> I'll forward to the list the stuff I sent Michael.

>      ---------- Forwarded message One----------
> 
> Date: Wed, 3 May 2000 09:35:32 -0600 (MDT)
> From: John Halleck <nahaj@u.cc.utah.edu>
> To: Michael Lake <Mike.Lake@uts.edu.au>
> 
> >   There are things I'd like to see, and didn't, in the area of data
> >   concerning survey adjustment.  But I suspect that that is not of
> >   general interest, so I'll take it up in private email.
> 
>   This is just off the top of my head, so take it with a grain of salt.
> 
> 1) Covariance of the instrument observations.  A symmetric 3x3 matrix, so one
>    only needs to store 6 numbers.
>    This is generally the same for an entire cave, but can change from shot to
>    shot in truely bizarre surveys.
>    99.9% of the time it is the same for an entire survey... so I'd consider it
>    a candidate for
>    <sometag D="..." A="..." I="..." DA="..." DI="..." AI="..."> survey </sometag>>
>    style marking.
>    [I'm assuming Distance Asimuth Inclination as was is measured.]
>    (D, A, and I are manditory, DA, DI, AI are optional)
> 
> 2) Covariance of the adjuted points.  Roughly the same as the above in form,
>    but with
>    <sometag X="...", Y="...", Z="...", XY="...", XZ="...", YZ="...">
> 

Whats the diff between a covariance for a point and its standard
deviation for a given instrument?
Is the covarience a statistical measure of how much it was adjustd by
the closure?
If its not exacly the same then at least it can be treated similarly,
though perhaps with a new tag if necessary.
Have a look at the Document Type Definition for the CaveSurveyXML.
Example DTD "CaveSurvey.dtd" at 
http://www.science.uts.edu.au/~mikel/cavescript/docs.html
Below is just a section of the DTD but as you will see whats here 
<!-- ============ The Survey Data ============ -->
<!ELEMENT SERIES ( (SURVEYORS?, INSTRUMENTS?)?, (STN+, SHOT+)+, XSECT*,
SERIES* >
<!ATTLIST SERIES 
          NAME        CDATA #REQUIRED
          DATE        CDATA #IMPLIED
          DECLINATION CDATA #IMPLIED          

<!ELEMENT STN (#PCDATA)>
<!ATTLIST STN 
          NAME   CDATA #REQUIRED
          EAST   CDATA #IMPLIED
          NORTH  CDATA #IMPLIED
          HEIGHT CDATA #IMPLIED
          dE     CDATA #IMPLIED
          dN     CDATA #IMPLIED
          dH     CDATA #IMPLIED

<!ELEMENT SHOT (#PCDATA)>
<!ATTLIST SHOT 
          FROM  CDATA               #REQUIRED
          TO    CDATA               #REQUIRED
          DIST  CDATA               #REQUIRED
          BEAR (CDATA | - )         #REQUIRED
          ELEV (CDATA | UP | DOWN ) #REQUIRED
          dDIST CDATA               #IMPLIED
          dBEAR CDATA               #IMPLIED
          dELEV CDATA               #IMPLIED
>

This means a Survey Series may contain the Surveyors and Instruments
tags but must contain at LEAST one but possibly more STN and SHOT tags.
There might be none or more cross sections ie XSECTs.
The STN tags must have a NAME attribute for each one and may contain
position information. The dE is error in Easting and likewise for dN and
dH is error in Height (In fact thats why I don't have a FIX tag - when
Survex data is turned into this XML format *fixes become STN elements
with dE, dN, and dH set to zero) 
The survey SHOT tag in any CaveSurveyXML document must
contain the atttributes DIST, BEAR and ELEV (ie D, A, I) and optionally
standard deviations from these values ie delta DIST which I call dDIST
etc. 


> I wouldn't mind having (but it would probably clutter the world) the
> ability to include (so that updates are minor) generated analysis
> data such as reference counts, and the spanning tree of the
> geometry matrix.

Uh? I've a lot to learn here. 

>     ---------- Forwarded message Two ----------
> On Wed, 3 May 2000, John Halleck wrote:
> 
> Almost any program that does any analysis of the data is going to
> have to assign a unique number to each survey point.  If this could
> be put in the data, then further analysis programs could use the
> previous numbers.  (The same could be said of shot numbers...)

Not needed in most cases. In XML one can have unique ID's attached to
tags but how I want to refer to other survey shots or stations is with
XML's Xpointer and Xlink constructs. Thats how I want to convert
imported Survex data *equates when I use my svx2xml script.
Just refer to all stations by their name. In cavern its say
/mycave.pitch1.extension.5 whereas in my XML format I nest the survey
series. My DTD allows this as so:
<!ELEMENT SERIES ( (SURVEYORS?, INSTRUMENTS?)?, (STN+, SHOT+)+, XSECT*,
SERIES* >  
A SERIES can contain ie zero or more other SERIES. An example is
example2.xml on my page.  

> If there is a range used put somewhere up front, then combining
> sections could be made efficient.

Again use the powerful Xlink and Xpointer so then linking surveys is
like linking HTML documents. But unlike HTML you dont need to insert
anything at the place where you want to link to but thats another story. 

Mike

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Michael Lake
University of Technology, Sydney
Email: mailto:Mike.Lake@uts.edu.au Ph: 02 9514 1724 Fx: 02 9514 1628 
URL: http://www.science.uts.edu.au/~mikel
Linux enthusiast, active caver and interested in anything technical.
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