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Workstation Presentations 1 Monday, Nov. 3
WS 1.1Software Tools for preparing a GEOPHYSICS paper or
Expanded AbstractR. Phillip Bording *, Institute for Geophysics,
The University of Texas at Austin
SummaryThe preparation of a paper for publication inGEOPHYSICS
or an Expanded Abstract of theannual meeting is real challenge.
This paperdiscusses presentation software tools which arereadily
available. Text editing tools are quitecommon these days, but the
preparation ofgraphs, plots, and animations for the new
on-linecomputer environment can be a real challenge.Here a method
of document preparation is pre-sented which allows for both hard
copy and elec-tronic media to be prepared in a consistent man-ner.
The use of LaTeX and the newer versionLaTeX2e and PostScript allow
for general sci-entifiever,
c document preparthe learning curve
Nation ican be
s discussed. How-steep and the use
of public domain software tools can make thisprocess less
difficult. Electronic media presenta-tions use markup languages
such as the Hyper-Text Meta-Language, HTML. By use of a consis-tent
set of tools it is possible to write one docu-ment and satisfy most
of the needs both the pa-per and electronic media development
process.
IntroductionThe preparation of text for publication is a nor-mal
part of the writing process. The writerscripts a detailed
description of the work per-formed and an analysis of the work. The
ab-stract and summary are used to create a suc-cinct paragraph or
two. The bibliography identi-fies other related work which can help
the readerunderstand the science and mathematics of thescholarly
effort of the author. The inclusion ofdrawings, images, pictures,
and equations helpthe reader visualize the concepts presented in
thetext. These tools assume the operating systemis UNIX.
The inclusion of these non-textual materials canbe quite
rewarding for they illustrate impor-tant points, they differentiate
between compet-ing methods, and generally reduce the wordinessof a
paper. The development of these visual ma-terials can be a real
chore. The pencil and paperera has passed andnew era of
software
hastools
been replaced with theand computer drafting.
In the first section a text editing system is re-viewed. The
basis for documentation must be atext editing system. In the next
several sectionstools are presented which can be used to
developnon-textual material for publication. A sectionis devoted to
the generation of animations usingseismic data. These animations
include multipleviews of different data from a computing
process.
Text EditingText editing is a complex process which benefitsfrom
computerization. A number of commercialand public domain software
packages are avail-able to assist a writer. These programs
automatethe transfer of hand written material into a ma-chine
readable form. They also allow the prepa-ration of the material in
an on-line fashion. Theauthor can use a visual interface and
generatea document directly. In some cases, the visualinterface
uses a WYSIWYG or what you see iswhat you get method of text input.
The re-quirements for text input are fairly simple. Canan input
device represent the characters of thelanguage the author is
comfortable in using? Theanswer is yes. The output requirements of
a textediting systems are a bit more demanding. Thepresentation of
textual material requires a signif-icant effort to position the
material on the paperpage or on the screen page. Further more wenow
can use a variety of fonts, character typefaces, and sizes to make
the presentation moreenjoyable and more readable.It is not the
purpose of this paper to compareor select a text editing system. I
use LaTeXas much as possible for preparing scientific doc-uments.
LaTeX allows significant support forformatting a text document with
a rich and com-plex set of type setting commands. For example,the
commands needed to place the section head-ing for these paragraphs
are given below.
\noindent\section*{\normalsize {\bf Text Editing))Notice that
these commands are readable,LaTeX does not use hidden control
codes. TheASCII character set has readable characters.
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Some word processing systems use escape codeswhich are not
representable as readable ASCIIcharacters. This can be an
undesirable feature.
Some text systems are easy to learn and use,some are more d i f
f icu l t and complex . Thelearning curve can present an obstacle
to usingL a T e X .
E q u a t i o n P r e p a r a t i o nThe inclusion of
mathematics into a documentcan increase the complexity of the
material be-ing presented. On the other hand, many ideasare
concisely represented by mathematical equa-tions. In geophysics, we
are constantly tryingmore difficult methods to solve seismic data
pro-cessing problems and the use of equations hasbecome essential
for stating and solving prob-lems.
However, frequent use of equations in an articlecan lead to a
high fog factor and is not recom-mended. It is far better to have a
few well ex-plained equations than to have too many. Thatsaid, we
need a good way to express equations.LaTeX has two good ways to
develop equations,the math mode which is invoked by using the
dol-lar sign, $expression
to wr. For
ap around a short mathematicalexample, a = b + c is an equa-
tion, and the following is an example of how easythe math mode
is to use.
F o r e x a m p l e , $ a = b + c $ i s a n e q u a t i o n
.
The other method is the equation mode whichcreates a separate
line or two of text material inthe form of a mathematical equation.
An exam-ple of the equation mode is given by writing theWave
Equation as follows:
+1
=
- - + (1)
The previous equation was developed using thefollowing
commands.
\ b e g i n ( c e n t e r )\ b e g i n ( e q u a t i o n
)\frac{\partial^2\Psi}{\partial
Software Tools
P l o t t i n g R e s u l t s w i t h P o s t S c r i p tIf a
custom plot is essential then it is possibleto generate a
PostScript compatible image di-rectly from executing programs. This
is similarto the method described for PLOTMTV. Anyprogramming
language which can output ASCIItext can generate a PostScript
compatible file.PostScript is really a programming language.Hence,
by construction of a set of correct com-mands it is possible to
make a plot which can besent to a printer which understands
PostScript.The identical process can be used for generationof a
file, and LaTeX understands how to includethese files. An example
is shown in Figure 1
Figure 1: FORTRAN Generated PostScript Ex-ample Plot
P l o t t i n g R e s u l t s w i t h P L O T M T VTo prepare
simple two dimensional plots a publicdomain package is available
called PLOTMTV.Using simple ASCII commands it is possible
togenerate respectable looking plots like the oneshown in Figure 2.
This is a powerful plottingpackage as it supports 2D and 3D
drawings. Theplot input can be generated by a FORTRAN orC program
and i s then inpu t to PLOTMTV.The user can manipulate the image
and cap-ture the desired plot to a PostScript file. ThesePostScript
fi les can be included in a LaTeXdocument.
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Software Tools
Figure 2: Source Function Example Plot
G e n e r a t i o n o f D r a w i n g s w i t h T e X D r a
wLaTeX can be used directly to generate verysimple drawings.
However, to make really use-ful drawings which are scale and pixel
size in-dependent it takes a drawing package like TeX-Draw. This
drawing package uses absolute andrelative move and draw commands to
make lines,place text, and to shade polygons. The result isa figure
or complex image which can be includedinto a LaTeX document or
output as a separatePostScript file.
S e i s m i c U N I X B i t m a p s a n d A n i m a t i o n
sSeveral useful software plotting programs can befound in the
Seismic Unix (SU) package avail-able from the Colorado School of
Mines. Seismictrace plot software called XWIGB will make ascreen
display of seismic data. An equivalentprogram uses the same data
input to generate aPostScript output file. An example is plotted
inFigure 3.
To make movies the SU program XMOVIE isused. This simple
X-Windows program uses auser generated input file which contains
frames of
data to create animations on the graphics screenof a computer
workstation. These movies canthen be recorded on videotape by VCR.
TheUNIX operating system is required. The inputfile consists of a
FORTRAN or C file which afterpreprocessing is converted into a cube
of datain floating point format. The face of the cubeis a single
frame image. Multiple sub-framescan placed inside to create a
single coordinatedmovie. An example of this movie generating
pro-cess will be presented.
E l e c t r o n i c D o c u m e n t sThe re-editing of text
information to create elec-tronic or on-line versions of a document
is timeconsuming. The HTML and HTML2 formats areASCII text based
and one can use the LaTeXstructure to prepare an electronic version
of adocument with some additional effort . Exam-ples of converted
documents and the methodsused will be presented.
C o n c l u s i o n sA variety of public domain software tools
exist toprepare plots, images, and animation sequences.These tools
are very useful for the preparationof scientific material for
publication.
A c k n o w l e d g e m e n t sI would like to acknowledge the
support of theU.S. Office of Naval Research grant
numberN00014-94-1-0508 for a two year post-doctoralfellowship.
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