As discussed in Section 1 on the Toolkit website (Magnetic Data - Background), the magnetic response will depend on the inclination, declination, and field strength of the magnetic field at the survey location.
To run the widget, select each cell below (greyed boxes below with "import json..." and "view = Simulator.worldViewerWidget...") and press [Shift+Enter], or select each cell and click on the 'Run' button in the menu at the top of the notebook.
Use the drop down menu below, which looks like this, to explore the range of responses (Total Magnetic Intensity) that would be measured if this same geologic (and magnetic rock properties) scenario existed at different locations on Earth. The red arrow at the bottom: illustrates the inclination and declination of the chosen location.
Notice how data collected at very low latitudes near the magnetic equator (e.g. Chile and Peru locations) show magnetic anomlies offset significantly from their source due to the near-horizontal magnetic inclinations existing at these locations. TMI data from these very low latitude locations are very difficult to interpret, and additional processing or filtering is typically necessary.
import json
from GeoToolkit.Mag import Simulator, DataIO
dataGrid = DataIO.loadGeoTiffFile("./assets/Synthetic/DataGrid.tiff", plotIt=False)
# cities = shapefile.Reader('./assets/worldShapefile/ne_10m_populated_places_simple.shp')
worldFile = './assets/Continents/continentDwnS50.shp'
# Load in the pre-defined locations
with open('./assets/MAGlocations_w_field.json', 'r') as fp:
sites = json.load(fp)
view = Simulator.worldViewerWidget(worldFile, sites, dataGrid, shapeFile='./assets/Synthetic/Synthetic_Zcontours.shp')
display(view)