North American Magnetic Anomaly Map: 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.
|US county names|
|USGS map quadrangles|
|Map quadrangle names|
Need more? You can View, Download, and Understand this data source at https://MRData.usgs.gov/magnetic/.
|Show available data layers|
|Layer not shown on map|
|50||Sliders affect layer transparency.|
|Show named geographic areas|
|Ohio||Click linked area names (subdivisions or overlapping areas)|
|Shows the area on the map|
|Click the map to show data near to the point you clicked.|
|A report opens in a new window.|
|Click the section headings to expand or collapse reports.|
|To select data from a rectangular area, hold the Ctrl key (use Cmd key on Macs) and drag the pointer.|
|Don't search a large area this way, it takes too long. Zoom in instead.|