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JEphem Ephemeris trail Units |
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Notations :
arcsec : arc second deg : degree h : hour km : kilometer m : meter rad : radian s : second (for time) au : astronomical unit |
UnitsConstants
. So constants to designate units are named :
DISTANCE_UNIT_XXX
, (ex : DISTANCE_UNIT_KM
)LINEAR_SPEED_UNIT_XXX
, ANGULAR_UNIT_XXX
and ANGULAR_SPEED_UNIT_XXX
.UnitConstants
also holds constants to designate unit type (units can be 'angular' units, 'distance' units etc..) :
TYPE_DISTANCE
TYPE_LINEAR_SPEED
TYPE_ANGULAR
TYPE_ANGULAR_SPEED
AstroContext.calcBodyCoords()
. The notion of unit group was developped to conveniently express particular groups of commonly used units.
int[] units = new int[]{DISTANCE_UNIT_AU, DISTANCE_UNIT_AU, DISTANCE_UNIT_AU};
int[] units = UNITGROUP_AU_AU_AU;
Units
' javadoc page for more details.
Body
need to store the units used to express their coordinates. This is done with two arrays of 3 integers that can be accessed through Body
's methods :
public int[] getPositionUnits()
public int[] getVelocityUnits()
public void setPositionUnits(int[] posUnits)
public void setVelocityUnits(int[] posUnits)
positionUnits
and velocityUnits
of bodies.sphereToCart()
and cartToSphere()
in class Body
).Ephemeris
) which display the coordinates.Units
APIUnits
provides these methods :
public static double[] convertUnits(double[] coords, int[] units1, int[] units2)
, to convert coordinates between a set of units to an other. public static String getUnitLabel(int unit)
, to get the english name of a unit.public static String getUnitLabels(int unitType)
, to get the english names of all units of a certain type.jephem.astro.tools.Ephemeris
don't use the two last methods, because they use labels stored in ressource files.
Units
is an abstract class. All its fields and methods are static.