Array Base Properties

In the database window, use the right-click menu option Array Base Properties to populate or edit the increment base property of a sensor data array channel.

Array Base Properties dialog options

Base

 

Depending on the type of geophysical data, the array increments may be time, distance or velocity. Select the appropriate type, or a type that fits your processing goal. Doing so will refresh the top most entry label, indicating the array size.

The options are:

  • None: Base property not assigned.
  • Time Windows (contiguous): You specify the time gates as a set of consecutive widths. Repeated widths can be entered using the concise syntax n x m. This is interpreted as the width m is repeated n times. If the number of provided Time windows is less that the dimension of the array, the last width is assigned to the remainder elements of the array. The dynamic table in the lower part of the dialog, tabulates the time widths (Width) and the centre value of each time gate (Time), see illustration.
  • Time Windows (discrete): You specify the time windows as a set of start: end times. The end of one time gate may overlap with the beginning of the next. These times are tabulated in the dynamic table in the lower part of the dialog (see illustration).
  • Frequencies: You specify the frequencies for each array element. These frequencies are tabulated in the dynamic table in the lower part of the dialog.

Units

Specifying the units is optional. The units drop-down list is populated in context with the Base specified.

Initial value |

Delay time |

Base frequency

The label of this entry is contextually set and depends on the nature of the Base parameter. The first element of the array may not be at zero. The Initial value, Delay time, Base frequency define the gap to the first element of the array. This attribute is stored in the data array header.

Time windows |

Increment |

Frequencies

The label is contextually set relative to the above parameter. You can enter the property increments in a few different ways.

Time windows is a special case generally used in IP. In this instance, both the intervals and the cumulative time are displayed.

The increment parameter allows you to define the increments of the selected base property.

The vertical axis of the Depth attribute increases downwards, while the vertical axis of the Elevation attribute increases upwards. Although you are not prevented from defining the Depth attribute with a negative increment, you are discouraged from doing so because this combination is equivalent to defining the Elevation attribute with a positive increment.

[Copy from...]

This button will appear only if there is at least one other array channel of an equal dimension that carries a base property.

If there is only one other such array, the name of the array will be shown on the button, otherwise clicking the button will pop up a list of arrays with on-board properties to choose from.

[Import from database]

Click this option if you have the property information in a database and the dialog Import Time Windows from Database will appear to prompt you for the required information.

[Export to database]

Click this option to save the property information as currently displayed to a database for later use. You will be prompted for the output database name.

Index offset

If the window database has more elements than the current array channel in focus, you may need to offset the 1st element of the array in focus and assign a later time to it.

Show hidden windows

Array elements for which no data has been supplied will not be displayed initially. If you would like to see these elements check this box.

Application Notes

The intent of this tool is to concatenate the size of the database, when the data array increment of a channel is the same throughout the database. This information is stored in and extracted from the channel header. A number of Oasis montaj extension tools require the array property information in order to proceed. This tool allows you to set the property, export, and import it.

The table at the end of the dialog shows the number of increments and their Start, Middle, End, and Width values.

Figure 1: Contiguous time windows. Time increments are provided as a set of consecutive time windows

Figure 2: Discrete time windows. Time gates are provided as a set of potentially overlapping start & end times.

Figure 3: The widths can also be constants.