Package pygeodesy :: Module utily |
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# Module utily

Geometric and other utility functions and constants.

After (C) Chris Veness 2011-2015 published under the same MIT Licence**, see Latitude/Longitude and Vector-based geodesy.

Version: 20.07.17

Functions
degrees(x) Convert angle x from radians to degrees. |
radians(x) Convert angle x from degrees to radians. |
acos1(x) Return math.acos(max(-1, min(1, x))). |
asin1(x) Return math.asin(max(-1, min(1, x))). |
atan2d(y, x) Compute `atan2(y, x)` to `degrees`. |
degrees90(rad) Convert radians to degrees and wrap [-270..+90]. |
degrees180(rad) Convert radians to degrees and wrap [-180..+180]. |
degrees360(rad) Convert radians to degrees and wrap [0..+360). |
degrees2m(deg, radius=6371008.77141, lat=0) Convert angle to distance along the equator or along a parallel at an other latitude. |
ft2m(feet, usurvey=False) Convert International or US Survey feet to meter. |
isNumpy2(obj) Check for an `Numpy2LatLon` points wrapper. |
isPoints2(obj) Check for an `LatLon2psxy` points wrapper. |
isTuple2(obj) Check for an `Tuple2LatLon` points wrapper. |
iterNumpy2(obj) Iterate over Numpy2 wrappers or other sequences exceeding the threshold. |
iterNumpy2over(n=None) Get or set the iterNumpy2 threshold. |
m2degrees(meter, radius=6371008.77141, lat=0) Convert distance to angle along equator or along a parallel at an other latitude. |
m2ft(meter, usurvey=False) Convert meter to International or US Survey feet (`ft`). |
m2km(meter) Convert meter to kilo meter (km). |
m2NM(meter) Convert meter to nautical miles (NM). |
m2SM(meter) Convert meter to statute miles (SM). |
radiansPI(deg) Convert and wrap degrees to radians [-PI..+PI]. |
radiansPI2(deg) Convert and wrap degrees to radians [0..+2PI). |
radiansPI_2(deg) Convert and wrap degrees to radians [-3PI/2..+PI/2]. |
sincos2(*rad) Return the `sine` and `cosine` of angle(s). |
sincos2d(*deg) Return the `sine` and `cosine` of angle(s) in `degrees`. |
splice(iterable, n=2, **fill) Split an iterable into `n` slices. |
tan_2(rad) Compute the tangent of half angle. |
tanPI_2_2(rad) Compute the tangent of half angle, 90 degrees rotated. |
unroll180(lon1, lon2, wrap=True) Unroll longitudinal delta and wrap longitude in degrees. |
unrollPI(rad1, rad2, wrap=True) Unroll longitudinal delta and wrap longitude in radians. |
wrap90(deg) Wrap degrees to [-270..+90]. |
wrap180(deg) Wrap degrees to [-180..+180]. |
wrap360(deg) Wrap degrees to [0..+360). |
wrapPI(rad) Wrap radians to [-PI..+PI]. |
wrapPI2(rad) Wrap radians to [0..+2PI). |
wrapPI_2(rad) Wrap radians to [-3PI/2..+PI/2]. |

Variables
| __all__ = `_ALL_LAZY.utily`

Function Details

### atan2d (y, x) |
Compute `atan2(y, x)` to `degrees`. See Also: Karney's C++ function Math.atan2d.

### degrees90 (rad) |
Convert radians to degrees and wrap [-270..+90]. Arguments: `rad` - Angle (`radians`). Returns: Angle in degrees, wrapped (`degrees90`).

### degrees180 (rad) |
Convert radians to degrees and wrap [-180..+180]. Arguments: `rad` - Angle (`radians`). Returns: Angle in degrees, wrapped (`degrees180`).

### degrees360 (rad) |
Convert radians to degrees and wrap [0..+360). Arguments: `rad` - Angle (`radians`). Returns: Angle in degrees, wrapped (`degrees360`).

### degrees2m (deg, radius=6371008.77141, lat=0) |
Convert angle to distance along the equator or along a parallel at an other latitude. Arguments: `deg` - Angle (`degrees`). `radius` - Mean earth radius (`meter`). `lat` - Parallel latitude (`degrees90`, `str`). Returns: Distance (`meter`, same units as `radius`). Raises: `RangeError` - Latitude `lat` outside valid range and rangerrors set to `True`. `ValueError` - Invalid `deg`, `radius` or `lat`. See Also: Function m2degrees.

### ft2m (feet, usurvey=False) |
Convert International or US Survey feet to meter. Arguments: `feet` - Value in feet (`scalar`). `usurvery` - Convert US Survey feet (`bool`), International feet otherwise. Returns: Value in `meter` (`float`). Raises: `ValueError` - Invalid `feet`.

### isNumpy2 (obj) |
Check for an `Numpy2LatLon` points wrapper. Arguments: `obj` - The object (any `type`). Returns: `True` if `obj` is an `Numpy2LatLon` instance, `False` otherwise.

### isPoints2 (obj) |
Check for an `LatLon2psxy` points wrapper. Arguments: `obj` - The object (any `type`). Returns: `True` if `obj` is an `LatLon2psxy` instance, `False` otherwise.

### isTuple2 (obj) |
Check for an `Tuple2LatLon` points wrapper. Arguments: `obj` - The object (any). Returns: `True` if `obj` is an `Tuple2LatLon` instance, `False` otherwise.

### iterNumpy2 (obj) |
Iterate over Numpy2 wrappers or other sequences exceeding the threshold. Arguments: `obj` - Points array, list, sequence, set, etc. (any). Returns: `True` do, `False` don't iterate.

### iterNumpy2over (n=None) |
Get or set the iterNumpy2 threshold. Arguments: `n` - Optional, new threshold (`int`). Returns: Previous threshold (`int`). Raises: `ValueError` - Invalid `n`.

### m2degrees (meter, radius=6371008.77141, lat=0) |
Convert distance to angle along equator or along a parallel at an other latitude. Arguments: `meter` - Distance (`meter`, same units as `radius`). `radius` - Mean earth radius (`meter`). `lat` - Parallel latitude (`degrees90`, `str`). Returns: Angle (`degrees`). Raises: `RangeError` - Latitude `lat` outside valid range and rangerrors set to `True`. `ValueError` - Invalid `meter`, `radius` or `lat`. See Also: Function degrees2m.

### m2ft (meter, usurvey=False) |
Convert meter to International or US Survey feet (`ft`). Arguments: `meter` - Value in meter (`scalar`). `usurvery` - Convert to US Survey feet (`bool`), International feet otherwise. Returns: Value in `feet` (`float`). Raises: `ValueError` - Invalid `meter`.

### m2km (meter) |
Convert meter to kilo meter (km). Arguments: `meter` - Value in meter (`scalar`). Returns: Value in km (`float`). Raises: `ValueError` - Invalid `meter`.

### m2NM (meter) |
Convert meter to nautical miles (NM). Arguments: `meter` - Value in meter (`scalar`). Returns: Value in NM (`float`). Raises: `ValueError` - Invalid `meter`.

### m2SM (meter) |
Convert meter to statute miles (SM). Arguments: `meter` - Value in meter (`scalar`). Returns: Value in SM (`float`). Raises: `ValueError` - Invalid `meter`.

### radiansPI (deg) |
Convert and wrap degrees to radians [-PI..+PI]. Arguments: `deg` - Angle (`degrees`). Returns: Radians, wrapped (`radiansPI`)

### radiansPI2 (deg) |
Convert and wrap degrees to radians [0..+2PI). Arguments: `deg` - Angle (`degrees`). Returns: Radians, wrapped (`radiansPI2`)

### radiansPI_2 (deg) |
Convert and wrap degrees to radians [-3PI/2..+PI/2]. Arguments: `deg` - Angle (`degrees`). Returns: Radians, wrapped (`radiansPI_2`)

### sincos2 (*rad) |
Return the `sine` and `cosine` of angle(s). Arguments: `rad` - One or more angles (`radians`). Returns: The `sin(rad)` and `cos(rad)` for each angle. See Also: GeographicLib function sincosd and C++ sincosd.

### sincos2d (*deg) |
Return the `sine` and `cosine` of angle(s) in `degrees`. Arguments: `deg` - One or more angles (`degrees`). Returns: The `sin(rad)` and `cos(rad)` for each angle. See Also: GeographicLib function sincosd and C++ sincosd.

### splice (iterable, n=2, **fill) |
Split an iterable into `n` slices. Arguments: `iterable` - Items to be spliced (`list`, `tuple`, ...). `n` - Number of slices to generate (`int`). `fill` - Optional fill value for missing items. Returns: A generator for each of `n` slices, iterable[i::n] for i=0..n. Raises: `ValueError` - Invalid `n`. Note: Each generated slice is a `tuple` or a `list`, the latter only if the `iterable` is a `list`. Example:
    >>> from pygeodesy import splice
    >>> a, b = splice(range(10))
    >>> a, b
    ((0, 2, 4, 6, 8), (1, 3, 5, 7, 9))
    >>> a, b, c = splice(range(10), n=3)
    >>> a, b, c
    ((0, 3, 6, 9), (1, 4, 7), (2, 5, 8))
    >>> a, b, c = splice(range(10), n=3, fill=-1)
    >>> a, b, c
    ((0, 3, 6, 9), (1, 4, 7, -1), (2, 5, 8, -1))
    >>> tuple(splice(list(range(9)), n=5))
    ([0, 5], [1, 6], [2, 7], [3, 8], [4])
    >>> splice(range(9), n=1)
    <generator object splice at 0x0...>

### tan_2 (rad) |
Compute the tangent of half angle. Arguments: `rad` - Angle (`radians`). Returns: tan(rad / 2) (`float`).

### tanPI_2_2 (rad) |
Compute the tangent of half angle, 90 degrees rotated. Arguments: `rad` - Angle (`radians`). Returns: tan((rad + PI/2) / 2) (`float`).

### unroll180 (lon1, lon2, wrap=True) |
Unroll longitudinal delta and wrap longitude in degrees. Arguments: `lon1` - Start longitude (`degrees`). `lon2` - End longitude (`degrees`). `wrap` - Wrap and unroll to the (-180..+180] range (`bool`). Returns: 2-Tuple (`lon2-lon1`, `lon2`) unrolled (`degrees`, `degrees`). See Also: Capability `LONG_UNROLL` in GeographicLib.

### unrollPI (rad1, rad2, wrap=True) |
Unroll longitudinal delta and wrap longitude in radians. Arguments: `rad1` - Start longitude (`radians`). `rad2` - End longitude (`radians`). `wrap` - Wrap and unroll to the (-PI..+PI] range (`bool`). Returns: 2-Tuple (`rad2 - rad1`, `rad2`) unrolled (`radians`, `radians`). See Also: Capability `LONG_UNROLL` in GeographicLib.

### wrap90 (deg) |
Wrap degrees to [-270..+90]. Arguments: `deg` - Angle (`degrees`). Returns: Degrees, wrapped (`degrees90`).

### wrap180 (deg) |
Wrap degrees to [-180..+180]. Arguments: `deg` - Angle (`degrees`). Returns: Degrees, wrapped (`degrees180`).

### wrap360 (deg) |
Wrap degrees to [0..+360). Arguments: `deg` - Angle (`degrees`). Returns: Degrees, wrapped (`degrees360`).

### wrapPI (rad) |
Wrap radians to [-PI..+PI]. Arguments: `rad` - Angle (`radians`). Returns: Radians, wrapped (`radiansPI`).

### wrapPI2 (rad) |
Wrap radians to [0..+2PI). Arguments: `rad` - Angle (`radians`). Returns: Radians, wrapped (`radiansPI2`).

### wrapPI_2 (rad) |
Wrap radians to [-3PI/2..+PI/2]. Arguments: `rad` - Angle (`radians`). Returns: Radians, wrapped (`radiansPI_2`).