Class EarthGravitationalModel
- Object
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- Formattable
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- AbstractMathTransform
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- VerticalTransform
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- EarthGravitationalModel
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- All Implemented Interfaces:
MathTransform
public final class EarthGravitationalModel extends VerticalTransform
Transforms vertical coordinates using coefficients from the Earth Gravitational Model.Aknowledgement
This class is an adaption of Fortran codeclenqt.for
from the National Geospatial-Intelligence Agency and available in public domain. The normalized geopotential coefficients file bundled in this module is an adaptation ofegm180.nor
file, with some spaces trimmed.- Since:
- 2.3
- Author:
- Pierre Cardinal, Martin Desruisseaux
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Nested Class Summary
Nested Classes Modifier and Type Class Description static class
EarthGravitationalModel.Provider
The provider forEarthGravitationalModel
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Nested classes/interfaces inherited from class AbstractMathTransform
AbstractMathTransform.Inverse
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Field Summary
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Fields inherited from class Formattable
SINGLE_LINE
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Method Summary
All Methods Instance Methods Concrete Methods Modifier and Type Method Description ParameterDescriptorGroup
getParameterDescriptors()
Returns the parameter descriptors for this math transform.ParameterValueGroup
getParameterValues()
Returns the parameters for this math transform.double
heightOffset(double longitude, double latitude, double height)
Returns the value to add to a height above the ellipsoid in order to get a height above the geoid for the specified geographic coordinate.protected void
load(String filename)
Loads the coefficients from the specified ASCII file and initialize the internal clenshaw arrays.-
Methods inherited from class VerticalTransform
getSourceDimensions, getTargetDimensions, transform, transform
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Methods inherited from class AbstractMathTransform
createTransformedShape, derivative, derivative, ensureNonNull, equals, formatWKT, getName, hashCode, inverse, isIdentity, needCopy, normalizeAngle, rollLongitude, transform, transform, transform, transform
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Methods inherited from class Formattable
cleanupThreadLocals, toString, toWKT, toWKT, toWKT, toWKT
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Methods inherited from interface MathTransform
toWKT
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Method Detail
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load
protected void load(String filename) throws IOException
Loads the coefficients from the specified ASCII file and initialize the internal clenshaw arrays.Note: ASCII may looks like an unefficient format for binary distribution. A binary file with coefficient values read by
DataInput.readDouble()
would be more compact than an uncompressed ASCII file. However, binary files are hard to compress by the ZIP algorithm. Our experience show that a 675 kb uncompressed ASCII file is only 222 kb after ZIP or JAR compression. The same data as a binary file is 257 kb uncompressed and 248 kb compressed. So surprisingly, the ASCII file is more compact than the binary file after compression. Since it is the primary format provided by the Earth-Info web site, we use it directly in order to avoid a multiplication of formats.- Parameters:
filename
- The filename (e.g."WGS84.cof"
, relative to this class directory.- Throws:
IOException
- if the file can't be read or has an invalid content.
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heightOffset
public double heightOffset(double longitude, double latitude, double height) throws TransformException
Returns the value to add to a height above the ellipsoid in order to get a height above the geoid for the specified geographic coordinate.- Specified by:
heightOffset
in classVerticalTransform
- Parameters:
longitude
- The geodetic longitude, in decimal degrees.latitude
- The geodetic latitude, in decimal degrees.height
- The height above the ellipsoid in metres.- Returns:
- The value to add in order to get the height above the geoid (in metres).
- Throws:
TransformException
- if the offset can't be computed for the specified coordinates.
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getParameterDescriptors
public ParameterDescriptorGroup getParameterDescriptors()
Returns the parameter descriptors for this math transform.- Overrides:
getParameterDescriptors
in classAbstractMathTransform
- Returns:
- The parameter descriptors for this math transform, or
null
. - See Also:
OperationMethod.getParameters()
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getParameterValues
public ParameterValueGroup getParameterValues()
Returns the parameters for this math transform.- Overrides:
getParameterValues
in classAbstractMathTransform
- Returns:
- A copy of the parameter values for this math transform, or
null
. - See Also:
Operation.getParameterValues()
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