Export to ASEG-GDF2

Use the Database > Export > ASEG-GDF menu option (EXPASEG GX) to export data from the active database to an ASEG-GDF2 file format with full support for projection. Either displayed data channels or all data channels may be exported. Additionally, you can export the displayed line, selected lines, or all lines. If the output files already exist, they will be overwritten.

Export to ASEG-GDF dialog options

ASEG-GDF2 DEFN file	Specify the ASEG-GDF2 header file (.dfn) that will contain the data formats. Script Parameter: EXPASEG.DEFN
ASEG-GDF2 data file	Specify the ASEG-GDF2 data file (.dat) that will contain the data, one record per line. Script Parameter: EXPASEG.DATA
ASEG-GDF2 description file	Specify the description file. The ASEG-GDF2 description file (.des or .txt) is an ASCII text file with no preset format, except that it contains the identifier "COMM" on every line. Script Parameter: EXPASEG.DESC
ASEG-GDF2 projection file	Specify the ASEG-GDF2 projection file (.prj) that will contain the projection parameters. Script Parameter: EXPASEG.PROJ
Channel with projection	From the list of database channels, select the channel associated with a projection. The projection file will not be created if the selected channel does not have a defined coordinate system. Script Parameter: EXPASEG.CHPROJ
Channels to save	Choose one of the following options to save the channels: Displayed channels All database channels Script Parameter: EXPASEG.CHAN
Lines/Groups to save	Choose one of the following options to save the lines/groups: Selected lines Displayed line All lines Script Parameter: EXPASEG.LINE

Application Notes

The description and projection files are optional, as is either the DEFN file or the data file.

If only the DEFN file name is given, the data file name is assumed to have the same name, and the extension ".dat". Similarly, if only the data file name is given, the DEFN file name is assumed to have the same name, and the extension ".dfn".

In the output file, the first parameter output is the channel number. For lines, this corresponds to the line number in Oasis montaj. For groups, a "0" is written, as groups do not generally have numbers for names.

If both groups and lines are present in a database, the behaviour is more complicated because groups tend to have channels unique to themselves.

Displayed line option: This works for a single group or line, and only the displayed group or line is output.
Selected lines option: If both lines and groups are selected, only the lines will be output. If only groups are selected, then only the first group will be output.
All lines option: If both lines and groups are present, then only the first group will be output.

This GX supports array channel exports. Dummy values are automatically converted to ASEG-GDF2 null values, determined by the output format. The output format width and number of decimals are derived from the channel settings. The format corresponds to the FORTRAN "F" notation.

Projection Parameters

The projection parameters are saved according to the ASEG-GDF2 standard. You can download the standard from the ASEG Technical Standards page.

However, this standard does not specify how datum transformation parameters should be stored. In order to save all the parameters, a new keyword "TRNS" is used, similar to the keyword "PROJ".