segy.read {RGeostats}R Documentation

Reading a SEGY File

Description

Reading a SEGY File

Usage

segy.read(filename, filecsv=NA, grid = NA, surfaces = NA, vartop = NA, varbot = NA, 
iline.min = NA, iline.max = NA, xline.min = NA, xline.max = NA, option = 0, 
flag.store = FALSE, nz_ss=NA, 
modif.high=NA, modif.low=NA, modif.scale=NA, verbose = 0, radix = "SEGY", 
modify.target = db.locmod())

Arguments

filename

Name of the SEGY file to be read

filecsv

Name of the CSV file where the traces must be stored (use option=2 and flag.store=-1)

grid

When provided, this argument provides the db-class (organized as a Grid where the information will be stored (if 'flag.store' is set to TRUE). This file is usually a 3-D file, unless this function is used to extract a line of traces. This argument is optional.

surfaces

When provided, this argument provides the db-class (organized as a Grid) which containing the limiting surfaces which define the interval where the SEGY must be read. This file is usually a 2-D Grid file. If this file is not provided, then the SEGY is read with no restriction along the vertical axis.

vartop

When the argument 'surfaces' is provided, the SEGY is read within an interval delineated by a Top and a Bottom surfaces. The argument 'vartop' is used to name the variable which will be used as the Top surface. If not provided, there is no limitation upwards.

varbot

When the argument 'surfaces' is provided, the SEGY is read within an interval delineated by a Top and a Bottom surfaces. The argument 'varbot' is used to name the variable which will be used as the Bottom surface. If not provided, there is no limitation downwards.

iline.min

This argument is used to restrict the reading of the SEGY by defining a minimum inline number. This value is inclusive. If the argument 'iline_min' and 'iline-max' are set to the same value, then they define a single line of traces to be extracted.

iline.max

This argument is used to restrict the reading of the SEGY by defining a maximum inline number. This value is inclusive. If the argument 'iline_min' and 'iline-max' are set to the same value, then they define a single (in) line of traces to be extracted.

xline.min

This argument is used to restrict the reading of the SEGY by defining a minimum crossline number. This value is inclusive. If the argument 'xline_min' and 'xline-max' are set to the same value, then they define a single (cross) line of traces to be extracted.

xline.max

This argument is used to restrict the reading of the SEGY by defining a maximum crossline number. This value is inclusive. If the argument 'xline_min' and 'xline-max' are set to the same value, then they define a single (cross) line of traces to be extracted.

option

Horizontalisation option, to be defined as:

  • 0 No horizontalization

  • -1 Horizontalization along the Bottom surface. No result is provided when this Bottom Surface is undefined.

  • 1 Horizontalization along the Top surface. No results is provided when this Top surface is undefined.

  • -2 Horizontalization along vertical by Squeeze and Stretch option from Bottom to Top surfaces

  • 2 Average the signal over the bench thickness. Note that the resulting matrix is a 2-D matrix.

flag.store

When 1, the values read from the SEGY are stored in the argument 'grid' which is returned as output argument.

When set to -1, the values are stored in a CSV file, trace per trace.

nz_ss

When stored using the squeeze-and-stretch option, the verticeal mesh is meaningless. Therefore user can specify the requested number of meshes. Otherwise, this number is read directly from the SEGY file.

modif.high,modif.low,modif.scale

It may happen that the values contained in a SEGY file have a large spread. The user can specify three values here such that each value, read from the SEGY, is: itemize - truncated below 'modif.high' - truncated above 'modif.low' - divided by 'modif.scale'.

verbose

Verbose flag

radix

Radix of the name given to the variable storing the results in the target Db.

modify.target

Decides whether or not the newly created variables will have their locator defined or not. For more information, see db.locmod.

Value

When 'flag.store' is TRUE, the function returns the input argument 'grid' to which the newly read information is added. When 'flag.store' is FALSE, a list is obtained which gives the characteristics of the resulting grid.

[Package RGeostats version 14.0.10 Index]