File formats

What the portal accepts today, how to prepare it, and how to export it from the software you already use.

Accepted today

Format	Files to upload	Notes
ASEG-GDF2	the `.dfn` (definition) and its `.dat` (data); the `.des` too if you have it	The `.des` often names the coordinate system and zone. Null values declared in the `.dfn` are treated as missing readings.
Located CSV	the `.csv`; its `.ddf` description file too if you have one	A header row of column names, then one row per station. Comma, tab or semicolon separated.
Line database (with `INDEX.PD`)	the database folder as one `.zip`	The zip must hold the database's `INDEX.PD` and `INDEX.vec` with the rest of its files.
Geosoft database	the `.gdb`	Lines, channels, units and the coordinate system are read from the database. Geosoft's missing-value markers are treated as missing readings. Channels holding several values per reading (for example EM gates) are not read. A database with a feature we have not seen before is refused with "This GDB file has a feature we have not seen; contact support."
Geosoft XYZ	the `.xyz` (or `.txt`)	The ASCII export: `Line` and `Tie` headers, a `/` line naming the columns just before the data, and `*` for a missing reading.
Grids	an ER Mapper `.ers` and its data file (same name, no extension; its `.isi` too if you have it), a Geosoft `.grd` (with its `.prj` if you have one), or a GXF	You draw lines across the grid on the map; see Grids below.

Up to 300 MB per upload. For a .zip, both the zip and what it expands to must fit.
Files are recognised by what is in them, not by their names. Choose all the files of one survey or grid together (for example the .ers and its data file).
Uploads expire two hours after the last change.
Line names may use letters, digits, spaces and . : + # ( ) / -, at most 64 characters. A file with any other character in a line name is refused; rename the lines and export again.

Coming soon

GeoTIFF grids coming

Surveys from any country

Every format on this page is accepted for a survey flown anywhere in the world, not only in Australia, as long as its positions are in a coordinate system with an EPSG code (see Coordinates). Files are stored in Australia (Sydney) wherever the survey was flown. The public map layers are Australian.

What the file must contain

A line number or name for every station (a grid has none: you draw the lines).
Positions: easting and northing, or longitude and latitude, for every station. When longitude and latitude do not say which datum they are on, you choose it: GDA94, GDA2020 or WGS 84 (WGS 84 outside Australia; see Coordinates). Nothing is submitted until you do.
The measured field: total magnetic intensity (nT) or the vertical component of gravity (mGal). Not a derived product.
Optional: the sensor elevation and the ground elevation (DTM). When the portal recognises both, the section figure is drawn in elevation with the ground surface.

Grids

A grid is shown on the map. Press Draw, click points along the line you want on the map, press Finish, and Save lines. Each line is read from the grid one cell apart, and you see its profile. Lines you saved before stay when you save more; press Clear first to start again. The lines then appear in the list like the lines of a survey: pick them, enter a target depth and check the lines.

The cell size sets the shallowest depth. The readings along a drawn line are one grid cell apart, and the station spacing must be no more than a tenth of the target depth, exactly as for a flown line. A finer spacing would only be made up between cells, so it is not used.

Grid cell Shallowest target depth

400 m 4,000 m

50 m 500 m

20 m 200 m

For shallower targets, upload the flight lines the grid was made from.
Empty cells are never filled. A line that crosses empty (null) cells or runs off the grid keeps only its longest unbroken piece, and says so; a line with too little left is refused.
Derived grids are refused: a vertical derivative (1VD, 2VD), reduced to the pole, analytic signal, tilt, upward continued or otherwise filtered grid is not the measured field. Upload the measured magnetic (total magnetic intensity) or gravity grid.
Several bands: choose the band; the same rule applies to each band.
A rotated grid is refused; re-grid it north-up.
The report says that its input was a profile drawn across a grid, and gives the cell size.

Grid cell	Shallowest target depth
400 m	4,000 m
50 m	500 m
20 m	200 m

Located CSV: the details

The first row holds the column names. Every row after it is one station.
Column names the portal recognises without a .ddf: line: LINE, LINENUMBER, LINE_NUMBER, FLTLINE, LINE_NO, LINEID; easting: X, EAST, EASTING, XCOORD, X_COORD; northing: Y, NORTH, NORTHING, YCOORD, Y_COORD; longitude and latitude: LONGITUDE, LONG, LON, LATITUDE, LAT (upper or lower case).
Leave missing readings empty. An empty cell, or a non-numeric one such as *, is read as a missing reading. A numeric dummy such as -99999 is not recognised as missing in a CSV and would be read as a real value.
A .ddf description file beside the CSV names the coordinate columns and the layout exactly; upload it with the CSV when you have it.

From Oasis montaj

Simplest: upload the database (.gdb) itself, or a grid (.grd). Or export:

Open the survey database and display the channels you want to send: the line, X and Y, longitude and latitude if you have them, the measured field channel, and the elevation channels if you have them.
Check the database's coordinate system and note its name, for example GDA94 / MGA zone 51. You may need it in step 2 of the portal.
Export to XYZ, ASEG-GDF2 (shown as ASEG-GDF in some versions) or CSV with a header row. Keep the .dfn, .dat and, if written, the .des together. Missing values written as empty cells or as * are read as missing; a numeric dummy in a CSV is not.
Upload the files in the portal.

From a line database (.ddf, INDEX.PD)

Grids: upload the .ers with its data file (and its .isi).
Simplest: zip the whole line database folder (the folder that holds INDEX.PD and INDEX.vec) and upload the .zip.
Or export the database to ASEG-GDF2 and upload the .dfn, .dat and .des.
Or export to CSV and upload it with the .ddf description file written beside it.

From any other software or a spreadsheet

Save as CSV with one header row and one row per station, each line's stations in sequence along the line.
Include a line column, the eastings and northings (and longitude and latitude if you have them) and the measured field (see the column names above).
Leave missing readings empty.
Note the coordinate system the positions are in; the portal will ask if it cannot tell.