Magnetic anomaly maps and data for North America

Airborne measurement of the earth's magnetic field over all of North America provides gridded data describing the magnetic anomaly caused by variations in earth materials and structure.

View

Show in a web browser window:

reduced-size image of the interactive map

North America

Show in Google Earth or other KML viewer:

NorthAmericanMagneticMap.kml (uncompressed KML file 2k byte)

Show in your GIS using OGC web services:

https://www.sciencebase.gov/arcgis/services/mrt/NAmag_webmerc/MapServer/WMSServer?request=GetCapabilities&service=WMS&version=1.3.0 (WMS, version 1.3.0)

https://mrdata.usgs.gov/mapcache/wmts (WMTS, version 1.0.0)

Download

Select detailed aeromagnetic surveys by state or county

ArcGIS grid format
Area	Magnetic anomaly Residual total intensity	Filtered anomaly high-pass 500km	Residual using satellite baseline	Size
North America	NAmag_origmrg.zip	NAmag_hp500.zip	NAmag_CM.zip	316 MB
Continental US	USmag_origmrg.zip	USmag_hp500.zip	USmag_CM.zip	46 MB

Geosoft grid format
Area	Magnetic anomaly Residual total intensity	Filtered anomaly high-pass 500km	Residual using satellite baseline	Size
North America	NAmag_origmrg.grd NAmag_origmrg.grd.gi	NAmag_hp500.grd NAmag_hp500.grd.gi	NAmag_CM.grd NAmag_CM.grd.gi	227 MB
Continental US	USmag_origmrg.grd USmag_origmrg.grd.gi	USmag_hp500.grd USmag_hp500.grd.gi	USmag_CM.grd USmag_CM.grd.gi	33 MB

(*.grd format is compatible with Oasis montaj viewer software)

Original grid data, in open grid formats
Download	Format	Size
magnetic.gxf.gz	Grid Exchange Format (Albers NAD27), gzipped	11 MB
magnetic.xyz.gz	XYZ text format (Geographic NAD27), gzipped	23 MB

Documentation

Metadata:

Outline - Questions & Answers - Plain text - XML

Publication

Digital data grids for the magnetic anomaly map of North America

Bankey, Viki, Cuevas, Alejandro, Daniels, David, Finn, Carol A., Hernandez, Israel, Hill, Patricia, Kucks, Robert, Miles, Warner, Pilkington, Mark, Roberts, Carter, Roest, Walter, Rystrom, Victoria, Shearer, Sarah, Snyder, Stephen, Sweeney, Ronald E., Velez, Julio, Phillips, J.D., and Ravat, D.K.A., 2002, Digital data grids for the magnetic anomaly map of North America: U.S. Geological Survey Open-File Report 2002-414, https://doi.org/10.3133/ofr02414.