App2truedip software

Purpose

Method

This program was originally designed to restore strike and dip of planar structures measured as two apparent dips on ODP Leg 176 cores. It relies on methods used during ODP Leg 147 and previous hard rocks legs.

1. a strike measurement, made in a section perpendicular to the core axis
2. one apparent dip along the the saw cut, conventionally oriented E-W
3. one apparent dip perpendicular to the saw cut, therefore N-S

1. two apparent dips along the perpendicular E-W and N-S direction, or
2. one apparent dip along either the E-W or the N-S direction and a strike direction

To accept non perpendicular apparent dip measurements the possibility to input numerical azimuth format was added later during Leg 180.

The program is designed with the idea of creating the input file by extracting the relevant data from a typical structural spreadsheet and of pasting back the computation results into the same spreadsheet.

Acknowledgments

References

• ODP Initial Reports, Leg 147, Explanatory notes, structural geology, measurement of structures, pages 28-31
• ODP Initial Reports, Leg 176, Explanatory notes, structural geology, structural measurements, pages 14-15
• ODP Initial Reports, Leg 180, Explanatory notes, structural geology, structural measurements, pages 16-17

Input

• Input is read as FORTRAN free format
  ==> CHARACTER STRINGS NEED TO BE ENCLOSED WITHIN QUOTES
• Input can read
  • either from keyboard (to compute a few values),
  • or from an ASCII text file. This ASCII file can be made by saving a structural measurements spreasheet as tab delimited text. In that case, MAKE SURE TO ENCLOSE CHARACTER STRINGS WITHIN QUOTES (eventually use a text editor to substitute quoted characters for unquoted ones).
• File structure
  1. Header: the 1st line is assumed to be a header line and is not used for calculations.
  2. Data lines start from the 2nd line on.
• Two input formats are available:
  1. alphanumerical where the dip directions are given by the characters E, W, N, S or
  2. numerical where dip directions are given as numbers (in degrees)
  They only differ by the data line format. These formats cannot be mixed in the same file.
  
  
• Data line structure
  
  
  1. Alphanumerical format
     
     There are 2 possible input data line format that correspond to two different types of measurements.
     
     
     • Case 1: two apparent dips
       • Give E or W dip first.
       • Do not put zero dip as first data.
       • Dip angles are in degrees.

       Column:	1	2	3	4	Comments
       Data:	apparent dip 1	azimuth 1	apparent dip 2	azimuth 2
       Type:	real	character	real	character
       Range:	]0, 90]	'E','W'	[0, 90]	'N','S'
       acceptable data:
       	16	'E'	50	'S'
       	16	'W'	50	'S'
       	16	'E'	50	'N'
       	16	'W'	50	'N'
       	16	'W'	0	'N'
       rejected data:					explanation
       	16	'N'	50	'E'	the E-W data must be first
       	0	'W'	50	'S'	zero dip data should be entered either second, or as strike (as in case 2 below: 50 'S' 270 'A')

       
       
     • Case 2: one apparent dip + one strike direction
       • Strike is given as second value and followed by a 'A' (meaning Azimuth data)
       • Strike should be chosen so that dip is to the right (if not, it will be corrected)
       • First dip data can be along E, W, N or S
       • Dip and strike angles are in degrees.

       Column:	1	2	3	4	Comments
       Data:	apparent dip 1	azimuth 1	strike	strike indicator
       Type:	real	character	real	character
       Range:	]0, 90]	'E','W','N','S'	[-360, +360]	'A'
       acceptable data:
       	16	'E'	50	'A'
       	16	'W'	230	'A'
       	16	'S'	50	'A'
       	16	'N'	230	'A'
       	50	'S'	270	'A'
       incorrect data that will be corrected:					explanation
       	16	'W'	50	'A'	The strike will be corrected to 230

       
       
     • Sample file = appdip.test.in.txt
     
     
  2. Numerical format
     
     The only restriction is not to put zero dip as the first data.

     Column:	1	2	3	4	Comments
     Data:	apparent dip 1	azimuth 1	apparent dip 2	azimuth 2
     Type:	real	real	real	real
     Range:	]0, 90]	[-360, +360]	[0, 90]	[-360, +360]
     acceptable data:
     	16	90	50	180
     	16	270	50	180
     	16	90	50	0
     	16	270	50	0
     	16	270	0	0
     rejected data:					explanation
     	0	270	50	180	zero dip data should be entered second

Output

• The first line is the header.
• Other lines are data lines and repeat the input followed by the computed strike and dip, and a explanation if a problem in the input data precluded computation.
• The fields are tab-delimited so as to facilitate import and copying and pasting the computation results in a structural spreadsheet.

1. Alphanumerical format
   
   

   Column:	1	2	3	4	5	6	7
   1st line = header	dipa1	dipdir1	dipa2	dipdir2	strike	dip	comment
   data line: case 1	1st apparent dip input	1st apparent dip direction input	2nd apparent dip input	2nd apparent dip direction input	absolute strike (**)	absolute dip	(**)
   Range: case 1	]0, 90]	'E','W'	[0, 90]	'N','S'	[0, +360]	[0, 90]
   data line: case 2	1st apparent dip input	1st apparent dip direction input	strike input (*)	'A'	absolute strike (***)	absolute dip	(**)
   Range: case 2	]0, 90]	'E','W','N','S'	[-360, +360]	'A'	[0, +360]	[0, 90]
   Type:	real	character	real	character	real	real	character string

   
   (*) : Eventually corrected so that dip is to the right
   (**): Eventual explanation of the data problem that precluded computation
   (***): Such that dip is to the right
   
   
2. Numerical format
   
   

   Column:	1	2	3	4	5	6	7
   1st line = header	dipa1	dipdir1	dipa2	dipdir2	strike	dip	comment
   data line	1st apparent dip input	1st apparent dip direction input	2nd apparent dip input	2nd apparent dip direction input	absolute strike(***)	absolute dip	(**)
   Range	]0, 90]	[-360, +360]	[0, 90]	[-360, +360]	[0, +360]	[0, 90]
   Type:	real	real	real	real	real	real	character string

   
   (**): Eventual explanation of the data problem that precluded computation
   (***): Such that dip is to the right

Installation

System independent: 2 files

1. Documentation (= this file).
2. Sample input file: appdip.test.in.txt

System dependent: 1 executable and 1 ReadMe

Applications and documents for various systems

Computer	Processor	Operating System	Downloads	Read Me !
Macintosh	68020, 68030, 6040	MacOS 7 - 8	app2truedip1-68020nofpu application	MacOS Classic versions
Macintosh	PPC	MacOS 7 - 9	app2truedip2-ppc application	MacOS Classic versions
Macintosh	PPC	MacOS X.4 - X.5	app2truedip2.mrwe application	MacOS X versions
Macintosh	Intel i86	MacOS X.4 - X.5, X.6 with Rosetta	app2truedip2.mrwe application	MacOS X versions

• Direct access to the binaries archive

Revision history

• Version 1.0: 30 July 1997
• Version 2.0: 22 June 1998    Alternate numerical input format.
• Version 2.0: 05 November 2004    MacOS X version.
• Version 2.1: 10 November 2004    Allows input from file or keyborad, output to file or screen.