2D Anomaly File (.grv .mag .mgx .mgy & .mgz extensions).
Note that the .mgx, .mgy and .mgz files contain magnetic compnent information.

This is an ASCII text file which has the following format:

333
0 51 36 25
-50.000000 0.000000 50000.000000
0.000000 0.000000 -5000.000000
10000.000000 7000.000000 0.000000
200.000000 0.400000
-13.618133 -13.516687 -13.610759 -14.060675 -14.92670…
-13.141494 -12.778272 -12.561273 -12.468239 -12.45922…
-12.516578 -12.034901 -11.651465 -11.359298 -11.13998…
-11.820199 -11.296333 -10.849636 -10.479922 -10.16345…
-11.109306 -10.585823 -10.122409 -9.702573 -9.321083…
-10.419118 -9.911049 -9.447624 -9.043615 -8.691870…
-9.761061 -9.272736 -8.820832 -8.384072 -7.958362…
-9.139796 -8.670816 -8.225464 -7.830383 -7.484703…
-8.554543 -8.098565 -7.666274 -7.223413 -6.771319…
-8.000542 -7.558571 -7.122763 -6.733661 -6.389823…
-7.478977 -7.038060 -6.609742 -6.148697 -5.657023…
-6.976142 -6.550281 -6.095707 -5.705247 -5.334617…
-6.506536 -6.068808 -5.614416 -5.123198 -4.558163…
-6.061280 -5.605092 -5.136177 -4.693969 -4.301543…
-5.630241 -5.159318 -4.671993 -4.108725 -3.456985…
-5.220694 -4.729609 -4.205978 -3.704633 -3.243653…

where the first six lines provide the following header information:

Then the following #rows lines are a set of #cols to a line magnetic or gravity anomaly values. Note that these values are floating point, and scaling and clipping is performed before an image is displayed within the program.

If you wish to import this image into another package simply skip the first 6 lines or 16 numbers and you have a simple ASCII array of data.