Import/Append Location Data

Use the Gravity > Locations > Import/Append Location Data menu option (GRLDXYE GX) to import location data into the location database of the gravity project.

Import/Append Location Data dialog options

Location database

The name of the location database. If the database does not exist, it will be created with channels of "Station", "Longitude", "Latitude", "X", "Y" and "Elevation". You will also have the option to load existing location data from another database or a text file.

Script Parameter: GRAVRED.LOCATION_DATABASE set by GRPARM GX

Location data source

Choose the data source as a Geosoft Database (gdb) file or a Text data file (see the Application Notes below for ASCII CSV file format requirements).

Script Parameter: GRLDXYE.TYPE

Load Location Data from Text Data File/ Database dialog options

Location file to load /Location survey database

Select the database or file to import based on the Location data source option.

Script Parameter: GRLDXYE.FILE

Overwrite existing locations?

Select the import option. If "Yes" is selected and the imported data contains stations already present in the location database, the existing locations will be deleted and replaced by the imported data stations. Note that the replacement row(s) will be appended at the end. If "No" is selected, any existing locations will be skipped.

  • If the imported data contains stations already present in the location database, the file MergeLocations.log is created in your working directory. The log file lists the stations that have been overwritten or skipped during the import.

    • Script Parameter: GRLDXYE.OVERWRITE [0 - No (default), 1-Yes]

    The next dialog is contextual and will only appear if any of the default channel names Station, Longitude, Latitude, are not found in the data source file.

    Select Master Channels

    Station channel

    Select the name of the station channel from the drop-down list of source file fields.

    Script Parameter: GRAVRED.STATION

    Longitude channel

    Select the name of the longitude channel from the drop-down list of source file fields.

    Script Parameter: GRAVRED.LONGITUDE

    Latitude channel

    Select the name of the latitude channel from the drop-down list of source file fields.

    Script Parameter: GRAVRED.LATITUDE

    If the above dialog is invoked, the log file, MergeLocations.log, is created (or updated) in your working directory. This log file lists the names of the imported fields to each of the channels, Station, Longitude, and Latitude.

    Application Notes

    Location data is loaded/ imported into the location database either from an existing Geosoft Database or from a comma delimited text file that contains location information. Regardless of the channel name discrepancy between the source file and the location database, the data is imported into the standard channels below.

    "Station"

    A unique station number that is used to look-up locations during the drift correction or when you merge location data using the "Merge with survey data…" (GRMGXYE GX).

    "Line"

    The "Line" channel will only be present if there is "Line" data in the imported location file. If "Line" is present, station locations are based on a unique Line and Station. This may be the case if a gravity survey is conducted on a local line/station oriented survey grid.

    "Longitude"
    "Latitude"

    The geographic location of the station. If only a local grid "X" or "Y" is provided, these values will appear as dummies. The "X,Y -> Longitude, Latitude…" (GRLL2XY GX) can be used to calculate longitudes and latitudes from local X,Y coordinates.

    "X"
    "Y"

    The local map X,Y coordinate of the station. The X,Y coordinates may also be in a known map projection. If only a longitude, latitude locations are provided, these values will be dummied. The "Longitude, Latitude -> X,Y…" (GRXY2LL GX) can be used to calculate X,Y coordinates from Longitude, Latitude coordinates.

    "Elevation"

    The station elevations.

    See Open/Create Location Database (GRXYEDB GX) for more information on establishing locations.

    ASCII CSV File Format

    Location data stored in an ASCII CSV file (Comma Separated Value) should look like one of the following examples (the order of the columns is not important):

    Station,Longitude,Latitude,X,Y,Elevation

    1,-89.2123166667,48.1929916667,100,0,340

    2,-89.2136722222,48.1942,100,25,342

    3,-89.2106166667,48.1948666667,100,50,329

    ...

    Line,Station,X,Y,Elevation

    100,0,100.25,0,340

    100,25,100.25,26.5,342

    100,50,105,52.1,329

    ...

    Station,Longitude,Latitude,Elevation

    1,-89.2123166667,48.1929916667,340

    2,-89.2136722222,48.1942,342

    3,-89.2106166667,48.1948666667,329

    ...

    Geographic coordinates can also be specified using the format "deg.mm.ss.ss".

    Distance Units

    Distance units are assumed to be degrees for geographic longitude, latitude and metres for "X", "Y" and "Elevation". The distance units can be changed when data is converted between X,Y and geographic coordinates, or the units can be set by editing the channel attributes and specifying the unit abbreviation (click once on a channel name, then right mouse and select "Edit").

    See Also: