Import ASEG-GDF

Use the Database > Import > ASEG-GDF > Import GDF (IMPASEG GX) to import ASEG-GDF data.

Import GDF dialog options

ASEG-GDF DEFN File	Input DEFN (header) file name. If not specified, the name of the DATA file is used (with a .dfn extension), and if no DATA file is specified, then the DEFN value from the template is used. By default, the browse window shows files with the ".dfn" extension. Script Parameter: IMPASEG.DEFN
ASEG-GDF Data File	Input data file name. If not specified, the name of the DEFN file is used (with a .dat extension), and if no DEFN file is specified, then the DATA value from the template is used. By default, the browse window shows files with the ".dat" extension. Script Parameter: IMPASEG.DATA
ASEG-GDF Description File (optional)	Input description file name (optional). The ASEG-GDF description file (.des or .txt) is an ASCII text file with no preset format, except it contains the identifier "COMM" on every line. By default, the browse window shows files with the ".txt" extension. Script Parameter: IMPASEG.DES
Flight Line channel Name	Flight Line Channel name. If not specified, the name indicated by the FLC parameter in the template is used. If no template is specified, and if no Flight line channel name is given, then by default the "Line" channel will be used. Script Parameter: IMPASEG.FLC
Template	Import template file name (.I4 assumed). If a template is not specified, then either the DEFN file or the Data file must be specified, and all the channels are imported with their original names. Script Parameter: IMPASEG.TEMPLATE
ASEG-GDF Projection File (optional)	Input projection file name. This parameter is optional. Script Parameter: IMPASEG.PROJ
X Channel to Associate with Projection	A channel to be associated with projection. The channel must be one of the channels in the data file. Script Parameter: IMPASEG.XCH
Y Channel to Associate with Projection	Another channel to be associated with projection. The channel must be one of the channels in the data file. Script Parameter: IMPASEG.YCH

Application Notes

Data may now be imported directly into a database using the IMPASEG GX, without using a pre-existing template. It is necessary, however, to specify at least one of the Data (.dat) or DEFN (.dfn) file names. If only one of the data or DEFN files is specified, the other is assumed to have the same name with the appropriate extension, either .dfn or .dat.

Import Templates

The import ASEG-GDF data may be customized by creating an import template file (with default extension .I4). This is an ASCII file that specifies the channels of data that you would like to import and the database channel in which you would like to place the data. The SCANASEG GX can be used to scan a given ASEG-GDF DEFN file and create a default import template that will import all data contained in the data file. Alternatively, if no template is specified when using the IMPASEG GX, a template is automatically created during import with the same name as the data file and with the .i4 extension. This may be edited and used to import a subset of channels, or rename channels on import.

Following is an example of a ASEG-GDF import template:

[IMPORT ASEG-GDF]

DEFN BOOTHILL.dfn

DATA BOOTHILL.dat

FLC FLTLINE

IMPORT FLIGHT,FLIGHT,SHORT

IMPORT DATE,DATE,LONG

IMPORT TIME,TIME,FLOAT

IMPORT FIDUCIAL,FIDUCIAL,FLOAT

IMPORT ALTITUDE,ALTITUDE,FLOAT

IMPORT TMAGRAW,TMAGRAW,FLOAT

ALIAS L20440,L20440

ALIAS L20450,L20450

The template file is searched for the line [IMPORT ASEG-GDF], and the IMPORT and ALIAS lines that follow are read to determine what data to import and the channels in which to place the data. You may add any comment line you wish before the [IMPORT ASEG-GDF] line.

DEFN syntax:

DEFN file_name

where file_name is the name of the ASEG-GDF DEFN file to import.

FLC syntax:

FLC flight_line_channel

where flight_line_channel is the name of the ASEG-GDF channel containing the flight line information.

IMPORT syntax:

IMPORT name, channel, type

The name is the name used in the ASEG-GDF DEFN file to indicate the data name. The channel is a mapping to the channel that will be created in the database. And the data type (one of BYTE, UBYTE, SHORT, LONG, FLOAT or DOUBLE) which should correspond to the type in the DEFN file.

ALIAS syntax:

ALIAS aseg_line_name,new_line_name

As the ASEG-GDF lines are imported, if a line-channel already exists in the database, it will be replaced. The ALIAS statement in the import template can be used to re-name lines of the ASEG-GDF data file during import. If the new_line_name is blank, the line will not be imported.

If ALIAS is used, ALL lines contained in the ASEG-GDF file must be defined by an ALIAS line in the same order that the lines appear in the file. The SCANASEG GX can be used to construct a default template that includes ALIAS lines for all lines of a file. This file can be edited as required by the system.

For example, if a file contains line L90, two sections of line L100 and a tie line L30, the following ALIAS lines can be used to import the data into properly named lines:

ALIAS L90,L90

ALIAS L100,L100.0

ALIAS L100,L100.1

ALIAS L30,T30

Setting Coordinate Systems

If the "Specify coordinate system on import" setting is set to "Yes" in the General Settings, and if no coordinate system is defined in the current X and Y channels, the "Georeference Database Channels" dialog is called so that the projection can be set on the X and Y.