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Utilities for point lists, tuples, etc.
Functions to handle collections and sequences of LatLon
points specified as 2-d NumPy, arrays
or tuples as
LatLon
or as pseudo-x/-y
pairs.
NumPy
arrays are assumed to contain rows of points with a
lat-, a longitude -and possibly other- values in different columns.
While iterating over the array rows, create an instance of a given
LatLon
class "on-the-fly" for each row with the
row's lat- and longitude.
The original NumPy
array is read-accessed only and never
duplicated, except to create a subset of the original array to be
returned.
For example, to process a NumPy
array, wrap the array by
instantiating class Numpy2LatLon and specifying the column index for the
lat- and longitude in each row. Then, pass the Numpy2LatLon instance to any pygeodesy function or
method accepting a points argument.
Similarly, class Tuple2LatLon is used to instantiate a
LatLon
from each 2+tuple in a sequence of such 2+tuples
using the ilat
lat- and ilon
longitude index in
each 2+tuple.
Version: 21.10.19
Classes | |
LatLon_ Low-overhead LatLon class for Numpy2LatLon and Tuple2LatLon.
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LatLon2psxy Wrapper for LatLon points as "on-the-fly"
pseudo-xy coordinates.
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Numpy2LatLon Wrapper for NumPy arrays as "on-the-fly"
LatLon points.
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Shape2Tuple 2-Tuple (nrows, ncols) , the number of rows and
columns, both int .
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Tuple2LatLon Wrapper for tuple sequences as "on-the-fly" LatLon points.
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Variables | |
__all__ = _ALL_LAZY.points
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Function Details |
Approximate the area of a polygon.
Note: This area approximation has limited accuracy and is ill-suited for regions exceeding several hundred Km or Miles or with near-polar latitudes. See Also: sphericalNvector.areaOf, sphericalTrigonometry.areaOf and ellipsoidalKarney.areaOf. |
Determine the lower-left SW and upper-right NE corners of a path or polygon.
See Also: Function quadOf. Example: >>> b = LatLon(45,1), LatLon(45,2), LatLon(46,2), LatLon(46,1) >>> boundsOf(b) # False >>> 45.0, 1.0, 46.0, 2.0 |
Determine the centroid of a polygon.
See Also: Centroid and Paul Bourke's Calculating The Area And Centroid Of A Polygon, 1988. |
Return the point at a given fractional index.
See Also: Class FIx and method FIx.fractional. |
Determine the direction of a path or polygon.
Example: >>> f = LatLon(45,1), LatLon(45,2), LatLon(46,2), LatLon(46,1) >>> isclockwise(f) # False >>> isclockwise(reversed(f)) # True |
Determine whether a polygon is convex.
Example: >>> t = LatLon(45,1), LatLon(46,1), LatLon(46,2) >>> isconvex(t) # True >>> f = LatLon(45,1), LatLon(46,2), LatLon(45,2), LatLon(46,1) >>> isconvex(f) # False |
Determine whether a polygon is convex and clockwise.
Example: >>> t = LatLon(45,1), LatLon(46,1), LatLon(46,2) >>> isconvex_(t) # +1 >>> f = LatLon(45,1), LatLon(46,2), LatLon(45,2), LatLon(46,1) >>> isconvex_(f) # 0 |
Determine whether a point is enclosed by a polygon.
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Check whether a polygon encloses a pole.
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Generate an ellipsoidal or spherical lune-shaped path or polygon.
See Also: Latitude-longitude quadrangle. |
Locate the point on a path or polygon closest to a reference point. The closest point is either on and within the extent of a polygon edge or the nearest of that edge's end points.
Note:
Distances are approximated using function pygeodesy.equirectangular_, subject to the
supplied See Also:
Function pygeodesy.nearestOn6 for cartesian points. Use
function pygeodesy.degrees2m to convert
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Approximate the perimeter of a path or polygon.
Note: This perimeter is based on the pygeodesy.equirectangular_ distance approximation and is ill-suited for regions exceeding several hundred Km or Miles or with near-polar latitudes. See Also: Functions sphericalTrigonometry.perimeterOf and ellipsoidalKarney.perimeterOf. |
Generate a quadrilateral path or polygon from two points.
See Also: Function boundsOf. |
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