Services Directory - EMAG2v3_hillshade

EMAG2v3_hillshade_wgs84 (Map Service)

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Current Version: 10.81

Service Description: EMAG2v3: the Earth Magnetic Anomaly Grid (2 arc-minute resolution), version 3 is compiled from satellite, ship, and airborne magnetic measurements. Magnetic anomalies result from geologic features enhancing or depressing the local magnetic field. These maps increase knowledge of subsurface structure and composition of the Earth's crust. Global magnetic anomaly grids are used for resource exploration, navigation where GPS is unavailable (submarine, directional drilling, etc.), and for studying the evolution of the lithosphere.

The 2017 release of the EMAG2v3 utilizes updated precompiled grids and a revised process for accurately incorporating the long-wavelength anomalies, as modeled by the satellite-based MF7 lithospheric field model. It is an update from the previous EMAG2v3 released by NCEI in 2016. EMAG2v3 further differs from the previous EMAG2 (version 2), which relied on an ocean age model to interpolate anomalies into non-existent data areas and on the earlier MF6 model. EMAG2v3 relies solely on the data available. As a result, EMAG2v3 better represents the complexity of these anomalies in oceanic regions and accurately reflects areas where no data has been collected. The current version reports anomalies in two ways:

A consistent altitude of 4 km (referred to as Upward Continued)
Anomaly altitude at Sea Level

This tile layer displays a color relief image of the EMAG2v3 (Upward Continued) rendered with a "hillshade" effect to simulate a 3D surface. A coastline is also provided for reference. The magnetic anomaly values in nanotesla (nT) are displayed using the color ramp below:
EMAG2v3 color scale

The EMAG2 dataset illustrates Earth evolution (plate tectonics and crustal interaction with the deep mantle). Distinct patterns and magnetic signatures are attributed to the formation (seafloor spreading) and destruction (subduction zones) of oceanic crust, and the formation of continental crust by accretion of various terranes to cratonic areas and large scale volcanism (both on continents and oceans).

Magnetization is weaker at the equator and stronger at high latitudes, reflecting the strength of the ambient geomagnetic field, which induces magnetization in rocks
Stripes of alternating magnetization in the oceans are due to sea floor spreading and the alternating polarity of the geomagnetic field
Very old crust (North American Shield, Baltic Shield, Siberian Craton) have strongest magnetization, seen as dark shades of purple and blue

There are four related ArcGIS services providing access to EMAG2v3:

Color shaded relief image (tiled, Web Mercator projection)
Color shaded relief image (tiled, WGS84 geographic)
Multi-layer map service
Image service (provides data values)

Map Name: EMAG2v3_color_relief_wgs84

Legend

All Layers and Tables

Layers:

EMAG2v3_color_relief_wgs84(0)

Tables:

Description: EMAG2v3: the Earth Magnetic Anomaly Grid (2 arc-minute resolution), version 3 is compiled from satellite, ship, and airborne magnetic measurements. Magnetic anomalies result from geologic features enhancing or depressing the local magnetic field. These maps increase knowledge of subsurface structure and composition of the Earth's crust. Global magnetic anomaly grids are used for resource exploration, navigation where GPS is unavailable (submarine, directional drilling, etc.), and for studying the evolution of the lithosphere.

The 2017 release of the EMAG2v3 utilizes updated precompiled grids and a revised process for accurately incorporating the long-wavelength anomalies, as modeled by the satellite-based MF7 lithospheric field model. It is an update from the previous EMAG2v3 released by NCEI in 2016. EMAG2v3 further differs from the previous EMAG2 (version 2), which relied on an ocean age model to interpolate anomalies into non-existent data areas and on the earlier MF6 model. EMAG2v3 relies solely on the data available. As a result, EMAG2v3 better represents the complexity of these anomalies in oceanic regions and accurately reflects areas where no data has been collected. The current version reports anomalies in two ways:

A consistent altitude of 4 km (referred to as Upward Continued)
Anomaly altitude at Sea Level

Magnetization is weaker at the equator and stronger at high latitudes, reflecting the strength of the ambient geomagnetic field, which induces magnetization in rocks
Stripes of alternating magnetization in the oceans are due to sea floor spreading and the alternating polarity of the geomagnetic field
Very old crust (North American Shield, Baltic Shield, Siberian Craton) have strongest magnetization, seen as dark shades of purple and blue

There are four related ArcGIS services providing access to EMAG2v3:

Color shaded relief image (tiled, Web Mercator projection)
Color shaded relief image (tiled, WGS84 geographic)
Multi-layer map service
Image service (provides data values)

Copyright Text: NOAA National Centers for Environmental Information (NCEI)

Spatial Reference:
4326

Single Fused Map Cache: true

Capabilities: Map,TilesOnly

Tile Info:

Height: 256
Width: 256
DPI: 96
Levels of Detail: (# Levels: 23)

Level ID: 0 [Start Tile, End Tile]
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Level ID: 22 [Start Tile, End Tile]

Format: JPEG
Compression Quality: 90
Origin:
Spatial Reference:
4326

Initial Extent:

Full Extent:

Min Scale: 2.958287637958547E8
Max Scale: 577790.5542887787

Min LOD: 0
Max LOD: 9

Units: esriDecimalDegrees

Supported Image Format Types: JPEG

Export Tiles Allowed: false
Max Export Tiles Count: 100000

Document Info:

Title: EMAG2v3: Earth Magnetic Anomaly Grid (Color Hillshade Image, WGS84 geographic)
Author: ncei_noaa
Comments:
Subject: Color hillshade visualization of the global magnetic anomaly grid from NOAA's National Centers for Environmental Information (NCEI), giving insight into the subsurface structure and composition of the Earth's crust.
Category:
Keywords: EMAG2v3, EMAG2, geomagnetism, magnetic anomaly, magnetism, magnetic model, geology, NOAA, NCEI