GeogravityModelData

GeogravityModelData[]

returns the gravitational field data for the current location.

GeogravityModelData[locationspec]

returns the gravitational field data for a location.

GeogravityModelData[locationspec,component]

returns the component of the gravitational field.

Details and Options

  • GeogravityModelData[] makes use of $GeoLocation to determine your location.
  • locationspec can be specified as latitude and longitude coordinates {lat,lon}, coordinates with a height {lat,lon,h}, GeoPosition[], or as a named Entity[]. h can be input as a numeric object in meters or as a Quantity.
  • locationspec can also be a region as specified by a named Entity[] or a listed pair of specific locations {locationspec1,locationspec2} or {locationspec1,locationspec2,h}.
  • Location can also be specified as Association["Location"->locationspec].
  • For regions, results are returned as arrays or an Association of arrays of gravitational fields by default. Arrays are calculated at the geographic height of a specific coordinate point of the grid above the reference datum unless otherwise specified. If that data is not available, it uses a default height of 0 meters.
  • Components include "NorthComponent", "EastComponent", "DownComponent", "HorizontalComponent", "Declination", "Inclination", and "Magnitude". Components are measured relative to the reference ellipsoid "WGS84Original".
  • "DownComponent" is measured relative to the perpendicular to the reference ellipsoid where positive values are downward. "HorizontalComponent" is the field parallel to the surface at that point. "Declination" is the angle between the north and east components. "Inclination" is the angle between the horizontal component and the vertical component. "Magnitude" is the total magnitude of the field. "Potential" is the gravitational potential.
  • Components and "Magnitude" are returned in meters per second squared. "Inclination" and "Declination" are returned in angular degrees. "Potential" is returned in joules per kilogram.
  • All gravitational field components are returned as an Association unless a specific component is requested.
  • GeogravityModelData[locationspec,component,func] is used to specify the format of output when extended locations are specified.
  • Possible settings for func include:
  • Allreturn all values for extended locations
    GeoVectorreturn components as a GeoVector object
    GeoVectorENUreturn components as a GeoVectorENU object
    Intervalreturn intervals for extended locations
    Maxreturn maximum values for extended locations
    Meanreturn mean value for extended locations
    Minreturn minumum values for extended locations
    StandardDeviationreturn standard deviation for extended locations
  • GeoVector and GeoVectorENU are not available for "Potential" or "Magnitude" components.
  • GeogravityModelData takes the following options:
  • MethodAutomaticspecific components to include in the calculation
    GeoZoomLevelAutomaticlevel of detail for gravitational field arrays
  • Method takes a suboption "ModelDegree" that controls the order of the gravitational model used. It can be set to integer values between 2 and 360 inclusive.
  • Method also takes a suboption "IncludeRotation" that can be set to True to include the effects of the Earth's rotation in the calculation of the acceleration field components.
  • The spatial resolution of the requested gravitational field data can be selected with the option GeoZoomLevelzoom, where zoom is an integer.
  • Data is based on EGM96 (Earth Gravitational Model 1996) on the WGS 84 ellipsoid.

Examples

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Basic Examples  (1)

Find the gravitational field components at a geographic position:

Use Entity to specify a location:

Scope  (10)

Location Specification  (5)

Find the gravitational field components for the current location:

Location can be given as a list of coordinates and local height:

Coordinates and height can be specified with Quantity:

Find an array of gravitational fields over a rectangular region defined by two points:

Points can be specified with GeoPosition or Entity:

Set the height at which the gravitational field will be calculated over the region:

Calculate the gravitational field over the region defined by an Entity:

Include a reference height:

Component Specification  (3)

Request specific components of the gravitational field:

Find the derived components of a gravitational field:

Calculate the magnitude of the gravitational field:

Format Specification  (2)

Find the range of the east component for an extended region:

Obtain the maximum or mean value of a component for a region:

Options  (4)

GeoZoomLevel  (1)

Control the size of the array produced for an extended region using GeoZoomLevel:

Method  (3)

Increase the accuracy of the results by increasing the "ModelDegree" setting for the Method option:

Examine how the down component changes with increasing degrees of the model:

Use "IncludeRotation" to examine the effect of the Earth's rotation on net gravitational acceleration:

Applications  (3)

Find the magnitude of the gravitational field at a location:

Calculate the angle to the vertical:

Calculate the inclination of the gravitational field for major cities in France:

Examine the distribution of values as a divergence from the vertical:

Examine how the gravity model deviates from the theoretical gravitational acceleration:

Possible Issues  (1)

Coordinates must be in the correct dimensions:

"ModelDegree" should be an integer between 2 and 360:

Neat Examples  (3)

Examine how the period differs in different locations for a 1-meter-long pendulum with a displacement of 1 degree:

Examine how the Earth's gravitational field differs from the standard value of 9.81 over a region:

Examine the magnitude of the gravitational field across the entire planet:

Introduced in 2015
 (10.1)
 |
Updated in 2019
 (12.0)