Package pygeodesy :: Module ellipsoidalKarney |
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# Module ellipsoidalKarney

Ellipsoidal, Karney-based geodesy.

Ellipsoidal geodetic (lat-/longitude) LatLon and geocentric (ECEF) Cartesian classes and functions areaOf, intersections2, isclockwise, nearestOn and perimeterOf, all requiring Charles Karney's geographiclib Python package to be installed.

Here's an example usage of `ellipsoidalKarney`:

    >>> from pygeodesy.ellipsoidalKarney import LatLon
    >>> Newport_RI = LatLon(41.49008, -71.312796)
    >>> Cleveland_OH = LatLon(41.499498, -81.695391)
    >>> Newport_RI.distanceTo(Cleveland_OH)
    866,455.4329098687  # meter

You can change the ellipsoid model used by the Karney formulae as follows:

    >>> from pygeodesy import Datums
    >>> from pygeodesy.ellipsoidalKarney import LatLon
    >>> p = LatLon(0, 0, datum=Datums.OSGB36)

or by converting to anothor datum:

    >>> p = p.toDatum(Datums.OSGB36)

Version: 23.05.12

Classes
| Cartesian Extended to convert `Karney`-based Cartesian to `Karney`-based LatLon points.
| LatLon An ellipsoidal LatLon similar to ellipsoidalVincenty.LatLon but using Charles F. F. Karney's Python geographiclib to compute the geodesic distance, initial and final bearing (azimuths) between two given points or the destination point given a start point and an (initial) bearing.

Functions
ispolar(points, wrap=False) Check whether a polygon encloses a pole. |
areaOf(points, datum=Datum(name='WGS84', ellipsoid=Ellipsoids.WGS84, transform=Tran`...`, wrap=True) Compute the area of an (ellipsoidal) polygon or composite. |
intersection3(start1, end1, start2, end2, height=None, wrap=False, equidistant=None, tol=0.001, LatLon=<class 'pygeodesy.ellipsoidalKarney.LatLon'>, **LatLon_kwds) Iteratively compute the intersection point of two lines, each defined by two (ellipsoidal) points or by an (ellipsoidal) start point and an (initial) bearing from North. |
intersections2(center1, radius1, center2, radius2, height=None, wrap=False, equidistant=None, tol=0.001, LatLon=<class 'pygeodesy.ellipsoidalKarney.LatLon'>, **LatLon_kwds) Iteratively compute the intersection points of two circles, each defined by an (ellipsoidal) center point and a radius. |
isclockwise(points, datum=Datum(name='WGS84', ellipsoid=Ellipsoids.WGS84, transform=Tran`...`, wrap=True) Determine the direction of a path or polygon. |
nearestOn(point, point1, point2, within=True, height=None, wrap=False, equidistant=None, tol=0.001, LatLon=<class 'pygeodesy.ellipsoidalKarney.LatLon'>, **LatLon_kwds) Iteratively locate the closest point on the geodesic between two other (ellipsoidal) points. |
perimeterOf(points, closed=False, datum=Datum(name='WGS84', ellipsoid=Ellipsoids.WGS84, transform=Tran`...`, wrap=True) Compute the perimeter of an (ellipsoidal) polygon or composite. |

Variables
| __all__ = `_ALL_LAZY.ellipsoidalKarney`

Function Details

### ispolar (points, wrap=False) |
Check whether a polygon encloses a pole. Arguments: `points` - The polygon points (`LatLon`[]). `wrap` - If `True`, wrap or normalize and unroll the `points` (`bool`). Returns: `True` if the polygon encloses a pole, `False` otherwise. Raises: `PointsError` - Insufficient number of `points` `TypeError` - Some `points` are not `LatLon` or don't have `bearingTo2`, `initialBearingTo` and `finalBearingTo` methods.

### areaOf (points, datum=Datum(name='WGS84', ellipsoid=Ellipsoids.WGS84, transform=Tran`...`, wrap=True) |
Compute the area of an (ellipsoidal) polygon or composite. Arguments: `points` - The polygon points (LatLon[], BooleanFHP or BooleanGH). `datum` - Optional datum (Datum). `wrap` - If `True`, wrap or normalize and unroll the `points` (`bool`). Returns: Area (`meter`, same as units of the `datum`'s ellipsoid axes, squared). Raises: `ImportError` - Package geographiclib not installed or not found. `PointsError` - Insufficient number of `points`. `TypeError` - Some `points` are not LatLon. `ValueError` - Invalid `wrap=False`, unwrapped, unrolled longitudes not supported. Notes: This function requires the geographiclib package. The area of a polygon enclosing a pole can be found by adding half the datum's ellipsoid surface area to the polygon's area. See Also: Functions pygeodesy.areaOf, ellipsoidalExact.areaOf, ellipsoidalGeodSolve.areaOf, sphericalNvector.areaOf and sphericalTrigonometry.areaOf.

### intersection3 (start1, end1, start2, end2, height=None, wrap=False, equidistant=None, tol=0.001, LatLon=<class 'pygeodesy.ellipsoidalKarney.LatLon'>, **LatLon_kwds) |
Iteratively compute the intersection point of two lines, each defined by two (ellipsoidal) points or by an (ellipsoidal) start point and an (initial) bearing from North. Arguments: `start1` - Start point of the first line (LatLon). `end1` - End point of the first line (LatLon) or the initial bearing at the first point (compass `degrees360`). `start2` - Start point of the second line (LatLon). `end2` - End point of the second line (LatLon) or the initial bearing at the second point (compass `degrees360`). `height` - Optional height at the intersection (`meter`, conventionally) or `None` for the mean height. `wrap` - If `True`, wrap or normalize and unroll the `start2` and `end*` points (`bool`). `equidistant` - An azimuthal equidistant projection (class or function pygeodesy.equidistant) or `None` for the preferred `start1.Equidistant`. `tol` - Tolerance for convergence and for skew line distance and length (`meter`, conventionally). `LatLon` - Optional class to return the intersection points (LatLon) or `None`. `LatLon_kwds` - Optional, additional `LatLon` keyword arguments, ignored if `LatLon is None`. Returns: An Intersection3Tuple`(point, outside1, outside2)` with `point` a `LatLon` or if `LatLon is None`, a LatLon4Tuple`(lat, lon, height, datum)`. Raises: `IntersectionError` - Skew, colinear, parallel or otherwise non-intersecting lines or no convergence for the given `tol`. `TypeError` - Invalid or non-ellipsoidal `start1`, `end1`, `start2` or `end2` or invalid `equidistant`. Note: For each line specified with an initial bearing, a pseudo-end point is computed as the `destination` along that bearing at about 1.5 times the distance from the start point to an initial gu-/estimate of the intersection point (and between 1/8 and 3/8 of the authalic earth perimeter). See Also: The ellipsoidal case and Karney's paper, pp 20-21, section 14. MARITIME BOUNDARIES for more details about the iteration algorithm.

### intersections2 (center1, radius1, center2, radius2, height=None, wrap=False, equidistant=None, tol=0.001, LatLon=<class 'pygeodesy.ellipsoidalKarney.LatLon'>, **LatLon_kwds) |
Iteratively compute the intersection points of two circles, each defined by an (ellipsoidal) center point and a radius. Arguments: `center1` - Center of the first circle (LatLon). `radius1` - Radius of the first circle (`meter`, conventionally). `center2` - Center of the second circle (LatLon). `radius2` - Radius of the second circle (`meter`, same units as `radius1`). `height` - Optional height for the intersection points (`meter`, conventionally) or `None` for the "radical height" at the radical line between both centers. `wrap` - If `True`, wrap or normalize and unroll `center2` (`bool`). `equidistant` - An azimuthal equidistant projection (class or function pygeodesy.equidistant) or `None` for the preferred `center1.Equidistant`. `tol` - Convergence tolerance (`meter`, same units as `radius1` and `radius2`). `LatLon` - Optional class to return the intersection points (LatLon) or `None`. `LatLon_kwds` - Optional, additional `LatLon` keyword arguments, ignored if `LatLon is None`. Returns: 2-Tuple of the intersection points, each a `LatLon` instance or LatLon4Tuple`(lat, lon, height, datum)` if `LatLon is None`. For abutting circles, both points are the same instance, aka the radical center. Raises: `IntersectionError` - Concentric, antipodal, invalid or non-intersecting circles or no convergence for the `tol`. `TypeError` - Invalid or non-ellipsoidal `center1` or `center2` or invalid `equidistant`. `UnitError` - Invalid `radius1`, `radius2` or `height`. See Also: The ellipsoidal case, Karney's paper, pp 20-21, section 14. MARITIME BOUNDARIES, circle-circle and sphere-sphere intersections.

### isclockwise (points, datum=Datum(name='WGS84', ellipsoid=Ellipsoids.WGS84, transform=Tran`...`, wrap=True) |
Determine the direction of a path or polygon. Arguments: `points` - The path or polygon points (`LatLon`[]). `datum` - Optional datum (Datum). `wrap` - If `True`, wrap or normalize and unroll the `points` (`bool`). Returns: `True` if `points` are clockwise, `False` otherwise. Raises: `ImportError` - Package geographiclib not installed or not found. `PointsError` - Insufficient number of `points`. `TypeError` - Some `points` are not `LatLon`. `ValueError` - The `points` enclose a pole or zero area. Note: This function requires the geographiclib package. See Also: pygeodesy.isclockwise.

### nearestOn (point, point1, point2, within=True, height=None, wrap=False, equidistant=None, tol=0.001, LatLon=<class 'pygeodesy.ellipsoidalKarney.LatLon'>, **LatLon_kwds) |
Iteratively locate the closest point on the geodesic between two other (ellipsoidal) points. Arguments: `point` - Reference point (`LatLon`). `point1` - Start point of the geodesic (`LatLon`). `point2` - End point of the geodesic (`LatLon`). `within` - If `True` return the closest point between `point1` and `point2`, otherwise the closest point elsewhere on the geodesic (`bool`). `height` - Optional height for the closest point (`meter`, conventionally) or `None` or `False` for the interpolated height. If `False`, the closest takes the heights of the points into account. `wrap` - If `True`, wrap or normalize and unroll both `point1` and `point2` (`bool`). `equidistant` - An azimuthal equidistant projection (class or function pygeodesy.equidistant) or `None` for the preferred `point.Equidistant`. `tol` - Convergence tolerance (`meter`). `LatLon` - Optional class to return the closest point (LatLon) or `None`. `LatLon_kwds` - Optional, additional `LatLon` keyword arguments, ignored if `LatLon is None`. Returns: Closest point, a `LatLon` instance or if `LatLon is None`, a LatLon4Tuple`(lat, lon, height, datum)`. Raises: `ImportError` - Package geographiclib not installed or not found. `TypeError` - Invalid or non-ellipsoidal `point`, `point1` or `point2` or invalid `equidistant`. `ValueError` - No convergence for the `tol`. See Also: The ellipsoidal case and Karney's paper, pp 20-21, section 14. MARITIME BOUNDARIES for more details about the iteration algorithm.

### perimeterOf (points, closed=False, datum=Datum(name='WGS84', ellipsoid=Ellipsoids.WGS84, transform=Tran`...`, wrap=True) |
Compute the perimeter of an (ellipsoidal) polygon or composite. Arguments: `points` - The polygon points (LatLon[], BooleanFHP or BooleanGH). `closed` - Optionally, close the polygon (`bool`). `datum` - Optional datum (Datum). `wrap` - If `True`, wrap or normalize and unroll the `points` (`bool`). Returns: Perimeter (`meter`, same as units of the `datum`'s ellipsoid axes). Raises: `ImportError` - Package geographiclib not installed or not found. `PointsError` - Insufficient number of `points`. `TypeError` - Some `points` are not LatLon or `closed=False` with `points` a composite. `ValueError` - Invalid `wrap=False`, unwrapped, unrolled longitudes not supported or `closed=False` with `points` a composite. Note: This function requires the geographiclib package. See Also: Functions pygeodesy.perimeterOf, ellipsoidalExact.perimeterOf, ellipsoidalGeodSolve.perimeterOf, sphericalNvector.perimeterOf and sphericalTrigonometry.perimeterOf.