Geodetic#

The library provides utilities to manage geodetic coordinates. There are other more exhaustive libraries that manage this domain, but some C++ objects need to receive this information from the Python code. This is why these objects have been developed.

World Geodetic System (WGS)#

This class allows describing the geodetic coordinate system used in the calculation. By default, the class instantiates the WGS84 system.

import timeit

import cartopy.crs
import cartopy.feature
import matplotlib.pyplot
import numpy

import pyinterp.geodetic

wgs84 = pyinterp.geodetic.Spheroid()
wgs84
Spheroid(6378137.0, 0.0033528106647474805)

You can instantiate other systems.

grs80 = pyinterp.geodetic.Spheroid((6378137, 1 / 298.257222101))
grs80
Spheroid(6378137.0, 0.003352810681182319)

World Geodetic Coordinates System#

This class is used internally to perform conversions from geodetic latitude, longitude, and altitude (LLA) coordinates to Earth-centered Earth-fixed (ECEF) coordinates. You can instantiate it from the Python, to do conversions or transformations.

lon = numpy.random.uniform(-180.0, 180.0, 1000000)
lat = numpy.random.uniform(-90.0, 90.0, 1000000)
alt = numpy.random.uniform(-10000, 100000, 1000000)

a = pyinterp.geodetic.Coordinates(wgs84)
b = pyinterp.geodetic.Coordinates(grs80)

elapsed = timeit.timeit('a.transform(b, lon, lat, alt, num_threads=0)',
                        number=100,
                        globals=dict(a=a, b=b, lon=lon, lat=lat, alt=alt))
print('transform: %f seconds' % (float(elapsed) / 100))
transform: 0.146177 seconds

Geodetic Point#

This class represents a point determined by its longitude and latitude expressed in degrees.

paris = pyinterp.geodetic.Point(2.3488, 48.8534)
new_york = pyinterp.geodetic.Point(-73.9385, 40.6643)

It is possible to instantiate these objects from the representation in Well-known text (WKT) format or to display it.

print(paris.wkt())
print(pyinterp.geodetic.Point.read_wkt(paris.wkt()) == paris)
POINT(2.3488 48.8534)
True

It’s possible to calculate the distances between the points using different strategies.

print(paris.distance(new_york, strategy='thomas', wgs=wgs84))
print(paris.distance(new_york, strategy='andoyer', wgs=wgs84))
print(paris.distance(new_york, strategy='vincenty', wgs=wgs84))
5851422.737557737
5851415.805549961
5851422.73938021

It is possible to do the same calculation on a large number of coordinates quickly.

lon = numpy.arange(0, 360, 10)
lat = numpy.arange(-90, 90.5, 10)
mx, my = numpy.meshgrid(lon, lat)
distances = pyinterp.geodetic.coordinate_distances(mx.ravel(),
                                                   my.ravel(),
                                                   mx.ravel() + 1,
                                                   my.ravel() + 1,
                                                   strategy='vincenty',
                                                   wgs=wgs84,
                                                   num_threads=1)
distances = distances.reshape(mx.shape)
print(distances[:, 0])
[  111693.86491427   113492.0455989    118205.54783325   124972.060567
   132725.47791087   140442.94773945   147269.62885486   152555.24897049
   155851.49814427   156899.5682913    155620.20173848   152110.33851807
   146647.19941715   139698.75539215   131935.96278038   124233.13141413
   117624.97692781   113170.2681493  19892237.59370932]

Geodetic Box & Polygon#

This class represents a box made of two describing points.

box = pyinterp.geodetic.Box(paris, new_york)
print(box.wkt())

#  %%
# A box is a polygon, but it is more easily constructed.
polygon = pyinterp.geodetic.Polygon.read_wkt(box.wkt())
print(polygon.wkt())
POLYGON((2.3488 48.8534,2.3488 40.6643,-73.9385 40.6643,-73.9385 48.8534,2.3488 48.8534))
POLYGON((2.3488 48.8534,2.3488 40.6643,-73.9385 40.6643,-73.9385 48.8534,2.3488 48.8534))

It’s possible to use different algorithms on these objects.

print(f'{polygon.area(wgs=wgs84) * 1e-3} km2')
4967683937.906199 km2

Transform this polygon into a bounding box

polygon = pyinterp.geodetic.Polygon.read_wkt('POLYGON((0 0,0 7,4 2,2 0,0 0))')
print(polygon.envelope())
((0, 0), (4, 7))

It is possible to use these objects to select coordinates in an area of interest.

coordinates = [[-36.25, -54.9238], [-36.5, -54.9238], [-36.75, -54.9238],
               [-37, -54.9238], [-37.25, -54.9238], [-37.5, -54.9238],
               [-37.75, -54.9238], [-38, -54.9238], [-38.25, -54.9238],
               [-38.5, -54.9238], [-38.75, -54.9238], [-39, -54.9238],
               [-39.25, -54.9238], [-39.5, -54.9238], [-39.75, -54.9238],
               [-40, -54.9238], [-40.25, -54.9238], [-40.5, -54.9238],
               [-40.75, -54.9238], [-41, -54.9238], [-41.25, -54.9238],
               [-41.5, -54.9238], [-41.75, -54.9238], [-42, -54.9238],
               [-42.25, -54.9238], [-42.5, -54.9238], [-42.75, -54.9238],
               [-43, -54.9238], [-43.25, -54.9238], [-43.5, -54.9238],
               [-43.75, -54.9238], [-44, -54.9238], [-44.25, -54.9238],
               [-44.5, -54.9238], [-44.75, -54.9238], [-45, -54.9238],
               [-45.25, -54.9238], [-45.5, -54.9238], [-45.75, -54.9238],
               [-46, -54.9238], [-46.25, -54.9238], [-46.5, -54.9238],
               [-46.75, -54.9238], [-47, -54.9238], [-47.25, -54.9238],
               [-47.5, -54.9238], [-47.75, -54.9238], [-48, -54.9238],
               [-48.25, -54.9238], [-48.5, -54.9238], [-48.75, -54.9238],
               [-49, -54.9238], [-49.25, -54.9238], [-49.5, -54.9238],
               [-49.75, -54.9238], [-50, -54.9238], [-50.25, -54.9238],
               [-50.5, -54.9238], [-50.75, -54.9238], [-51, -54.9238],
               [-51.25, -54.9238], [-51.5, -54.9238], [-51.75, -54.9238],
               [-52, -54.9238], [-52.25, -54.9238], [-52.5, -54.9238],
               [-52.75, -54.9238], [-53, -54.9238], [-53.25, -54.9238],
               [-53.5, -54.9238], [-53.75, -54.9238], [-54, -54.9238],
               [-54.25, -54.9238], [-54.5, -54.9238], [-54.75, -54.9238],
               [-55, -54.9238], [-55.25, -54.9238], [-55.5, -54.9238],
               [-55.75, -54.9238], [-56, -54.9238], [-56.25, -54.9238],
               [-56.5, -54.9238], [-56.75, -54.9238], [-57, -54.9238],
               [-57.25, -54.9238], [-57.5, -54.9238], [-57.75, -54.9238],
               [-58, -54.9238], [-58.25, -54.9238], [-58.5, -54.9238],
               [-58.75, -54.9238], [-59, -54.9238], [-59.25, -54.9238],
               [-59.5, -54.9238], [-59.75, -54.9238], [-60, -54.9238],
               [-60.25, -54.9238], [-60.5, -54.9238], [-60.75, -54.9238],
               [-61, -54.9238], [-61.25, -54.9238], [-61.5, -54.9238],
               [-61.75, -54.9238], [-62, -54.9238], [-62.25, -54.9238],
               [-62.5, -54.9238], [-62.75, -54.9238], [-63, -54.9238],
               [-63.25, -54.9238], [-63.5, -54.9238], [-63.75, -54.9238],
               [-64, -54.9238], [-64.25, -54.9238], [-64.5, -54.9238],
               [-64.75, -54.9238], [-65, -54.9238], [-65.25, -54.9238],
               [-65.5, -54.9238], [-66.25, -54.4905], [-66.5, -54.345],
               [-67.25, -54.0525], [-67.5, -53.9055], [-67.75, -53.7579],
               [-68, -53.4613], [-69.25, -52.5588], [-69.25, -52.4066],
               [-69.25, -52.2538], [-69, -51.1695], [-69, -51.0125],
               [-69, -50.855], [-69, -50.6969], [-69, -50.5383],
               [-68.75, -50.3791], [-67.5, -49.0865], [-67.5, -46.3975],
               [-67.5, -46.2248], [-67.5, -46.0515], [-67.25, -45.7035],
               [-67, -45.3532], [-66.25, -45.0007], [-65.25, -43.7499],
               [-65, -42.1026], [-65, -41.9168], [-65, -41.7305],
               [-65, -41.5437], [-65, -41.3563], [-65, -41.1684],
               [-65, -40.9799], [-64.75, -40.9799], [-62.25, -39.0656],
               [-62, -39.0656], [-61.75, -39.0656], [-61.5, -39.0656],
               [-61.25, -39.0656], [-61, -39.0656], [-60, -38.8713],
               [-59.75, -38.8713], [-58.25, -34.4619], [-58.25, -34.2555],
               [-58, -34.2555], [-57, -34.6678], [-55.75, -34.8731],
               [-55.5, -34.8731], [-53.5, -34.0486], [-53.25, -33.8412],
               [-53, -33.6333], [-52.5, -33.0066], [-52.25, -32.3754],
               [-52, -32.164], [-51.75, -31.9522], [-51.5, -31.7398],
               [-51, -31.3136], [-50.25, -30.4554], [-50, -29.8068],
               [-49.5, -29.1539], [-49.25, -28.9353], [-48.5, -27.1704],
               [-48.5, -26.9478], [-48.5, -26.7247], [-48.5, -26.5012],
               [-48.5, -26.2772], [-48.5, -26.0528], [-48.5, -25.828],
               [-48.25, -25.3771], [-47.75, -24.9245], [-47, -24.4703],
               [-46.75, -24.2425], [-46, -23.7858], [-44.5, -23.0977],
               [-44.25, -23.0977], [-44, -23.0977], [-43.75, -23.0977],
               [-43.5, -23.0977], [-41.75, -22.4061], [-41, -21.4785],
               [-40.75, -21.0125], [-40.25, -20.3107], [-40, -19.8411],
               [-39.5, -18.424], [-39.5, -18.1867], [-39, -16.7559],
               [-39, -16.5164], [-39, -15.0731], [-39, -14.8315],
               [-39, -14.5897], [-39, -14.3477], [-39, -14.1053],
               [-38.75, -13.1335], [-37.5, -11.9132], [-37.25, -11.4236],
               [-37, -10.933], [-35.75, -9.70328], [-35, -8.71619],
               [-34.75, -7.72648], [-34.75, -7.47867], [-36.75, -4.99367],
               [-37.25, -4.74457], [-38, -4.24611], [-38.25, -3.99675],
               [-39.25, -3.24826], [-39.75, -2.99863], [-40.75, -2.74894],
               [-41, -2.74894], [-41.25, -2.74894], [-41.5, -2.74894],
               [-41.75, -2.74894], [-42, -2.74894], [-44.25, -2.74894],
               [-44.5, -2.74894], [-46.5, -0.999949], [-48.25, -0.999949],
               [-48.5, -0.999949], [-48.5, -0.749979], [-48.5, -0.499994],
               [-48.5, -0.249999], [-48.25, -0.249999], [-48, -0.249999],
               [-47.75, -0.249999], [-47.5, -0.249999], [-47.25, -0.249999],
               [-47, -0.249999], [-46.75, -0.249999], [-46.5, -0.249999],
               [-46.25, -0.249999], [-46, -0.249999], [-45.75, -0.249999],
               [-45.5, -0.249999], [-45.25, -0.249999], [-45, -0.249999],
               [-44.75, -0.249999], [-44.5, -0.249999], [-44.25, -0.249999],
               [-44, -0.249999], [-43.75, -0.249999], [-43.5, -0.249999],
               [-43.25, -0.249999], [-43, -0.249999], [-42.75, -0.249999],
               [-42.5, -0.249999], [-42.25, -0.249999], [-42, -0.249999],
               [-41.75, -0.249999], [-41.5, -0.249999], [-41.25, -0.249999],
               [-41, -0.249999], [-40.75, -0.249999], [-40.5, -0.249999],
               [-40.25, -0.249999], [-40, -0.249999], [-39.75, -0.249999],
               [-39.5, -0.249999], [-39.25, -0.249999], [-39, -0.249999],
               [-38.75, -0.249999], [-38.5, -0.249999], [-38.25, -0.249999],
               [-38, -0.249999], [-37.75, -0.249999], [-37.5, -0.249999],
               [-37.25, -0.249999], [-37, -0.249999], [-36.75, -0.249999],
               [-36.5, -0.249999], [-36.25, -0.249999], [-36, -0.249999],
               [-35.75, -0.249999], [-35.5, -0.249999], [-35.25, -0.249999],
               [-35, -0.249999], [-34.75, -0.249999], [-34.5, -0.249999],
               [-34.25, -0.249999], [-34, -0.249999], [-33.75, -0.249999],
               [-33.5, -0.249999], [-33.25, -0.249999], [-33, -0.249999],
               [-32.75, -0.249999], [-32.5, -0.249999], [-32.25, -0.249999],
               [-32, -0.249999], [-31.75, -0.249999], [-31.5, -0.249999],
               [-31.25, -0.249999], [-31, -0.249999], [-30.75, -0.249999],
               [-30.5, -0.249999], [-30.25, -0.249999], [-30, -0.249999],
               [-29.75, -0.249999], [-29.5, -0.249999], [-29.25, -0.249999],
               [-29, -0.249999], [-28.75, -0.249999], [-28.5, -0.249999],
               [-28.25, -0.249999], [-28, -0.249999], [-27.75, -0.249999],
               [-27.5, -0.249999], [-27.25, -0.249999], [-27, -0.249999],
               [-26.75, -0.249999], [-26.5, -0.249999], [-26.25, -0.249999],
               [-26, -0.249999], [-25.75, -0.249999], [-25.5, -0.249999],
               [-25.25, -0.249999], [-25, -0.249999], [-24.75, -0.249999],
               [-24.5, -0.249999], [-24.25, -0.249999], [-24, -0.249999],
               [-23.75, -0.249999], [-23.5, -0.249999], [-23.25, -0.249999],
               [-23, -0.249999], [-22.75, -0.249999], [-22.5, -0.249999],
               [-22.25, -0.249999], [-22, -0.249999], [-21.75, -0.249999],
               [-21.5, -0.249999], [-21.25, -0.249999], [-21, -0.249999],
               [-20.75, -0.249999], [-20.5, -0.249999], [-20.25, -0.249999],
               [-20, -0.249999], [-19.75, -0.249999], [-19.5, -0.249999],
               [-19.25, -0.249999], [-19, -0.249999], [-18.75, -0.249999],
               [-18.5, -0.249999], [-18.25, -0.249999], [-18, -0.249999],
               [-17.75, -0.249999], [-17.5, -0.249999], [-17.25, -0.249999],
               [-17, -0.249999], [-16.75, -0.249999], [-16.5, -0.249999],
               [-16.25, -0.249999], [-16, -0.249999], [-15.75, -0.249999],
               [-15.5, -0.249999], [-15.25, -0.249999], [-15, -0.249999],
               [-14.75, -0.249999], [-14.5, -0.249999], [-14.25, -0.249999],
               [-14, -0.249999], [-13.75, -0.249999], [-13.5, -0.249999],
               [-13.25, -0.249999], [-13, -0.249999], [-12.75, -0.249999],
               [-12.5, -0.249999], [-12.25, -0.249999], [-12, -0.249999],
               [-11.75, -0.249999], [-11.5, -0.249999], [-11.25, -0.249999],
               [-11, -0.249999], [-10.75, -0.249999], [-10.5, -0.249999],
               [-10.25, -0.249999], [-10, -0.249999], [-9.75, -0.249999],
               [-9.5, -0.249999], [-9.25, -0.249999], [-9, -0.249999],
               [-8.75, -0.249999], [-8.5, -0.249999], [-8.25, -0.249999],
               [-8, -0.249999], [-7.75, -0.249999], [-7.5, -0.249999],
               [-7.25, -0.249999], [-7, -0.249999], [-6.75, -0.249999],
               [-6.5, -0.249999], [-6.25, -0.249999], [-6, -0.249999],
               [-5.75, -0.249999], [-5.5, -0.249999], [-5.25, -0.249999],
               [-5, -0.249999], [-4.75, -0.249999], [-4.5, -0.249999],
               [-4.25, -0.249999], [-4, -0.249999], [-3.75, -0.249999],
               [-3.5, -0.249999], [-3.25, -0.249999], [-3, -0.249999],
               [-2.75, -0.249999], [-2.5, -0.249999], [-2.25, -0.249999],
               [-2, -0.249999], [-1.75, -0.249999], [-1.5, -0.249999],
               [-1.25, -0.249999], [-1, -0.249999], [-0.75, -0.249999],
               [-0.5, -0.249999], [-0.25, -0.249999], [0, -0.249999],
               [0.25, -0.249999], [0.5, -0.249999], [0.75, -0.249999],
               [1, -0.249999], [1.25, -0.249999], [1.5, -0.249999],
               [1.75, -0.249999], [2, -0.249999], [2.25, -0.249999],
               [2.5, -0.249999], [2.75, -0.249999], [3, -0.249999],
               [3.25, -0.249999], [3.5, -0.249999], [3.75, -0.249999],
               [4, -0.249999], [4.25, -0.249999], [4.5, -0.249999],
               [4.75, -0.249999], [5, -0.249999], [5.25, -0.249999],
               [5.5, -0.249999], [5.75, -0.249999], [6, -0.249999],
               [6.25, -0.249999], [6.5, -0.249999], [6.75, -0.249999],
               [7, -0.249999], [7.25, -0.249999], [7.5, -0.249999],
               [7.75, -0.249999], [8, -0.249999], [8.25, -0.249999],
               [8.5, -0.249999], [8.75, -0.249999], [9, -0.249999],
               [9.25, -0.249999], [9.75, -2.49921], [10.25, -2.99863],
               [10.75, -3.49783], [11.25, -3.99675], [11.75, -4.74457],
               [12, -5.24267], [12.25, -5.98906], [12.75, -6.98265],
               [13, -7.72648], [13.25, -8.22164], [13.25, -8.46899],
               [13.25, -8.71619], [13.5, -10.4417], [13.75, -10.933],
               [13.75, -11.1784], [13.75, -11.4236], [13.75, -11.6685],
               [13.75, -11.9132], [13.5, -12.402], [12.5, -13.6199],
               [12.25, -14.5897], [12, -15.5553], [11.75, -16.7559],
               [12.5, -19.1341], [12.75, -19.6058], [13, -20.0761],
               [13.25, -20.545], [13.5, -21.0125], [13.75, -21.4785],
               [14.25, -22.1747], [14.5, -22.637], [14.5, -22.8675],
               [14.5, -24.2425], [14.75, -24.9245], [14.75, -25.151],
               [14.75, -25.3771], [15, -26.5012], [16, -28.2769],
               [16.5, -28.7163], [16.75, -29.1539], [17, -29.8068],
               [17.25, -30.4554], [17.5, -30.8855], [18, -31.5269],
               [18.25, -31.9522], [18.25, -32.164], [18.25, -32.3754],
               [19.25, -34.4619], [19.75, -34.8731], [19.75, -35.078],
               [19.75, -35.2823], [19.75, -35.4861], [19.75, -35.6894],
               [19.75, -35.8922], [19.75, -36.0945], [19.75, -36.2962],
               [19.75, -36.4975], [19.75, -36.6982], [19.75, -36.8984],
               [19.75, -37.098], [19.75, -37.2972], [19.75, -37.4958],
               [19.75, -37.6939], [19.75, -37.8914], [19.75, -38.0885],
               [19.75, -38.285], [19.75, -38.4809], [19.75, -38.6764],
               [19.75, -38.8713], [19.75, -39.0656], [19.75, -39.2595],
               [19.75, -39.4528], [19.75, -39.6456], [19.75, -39.8378],
               [19.75, -40.0295], [19.75, -40.2206], [19.75, -40.4113],
               [19.75, -40.6013], [19.75, -40.7909], [19.75, -40.9799],
               [19.75, -41.1684], [19.75, -41.3563], [19.75, -41.5437],
               [19.75, -41.7305], [19.75, -41.9168], [19.75, -42.1026],
               [19.75, -42.2878], [19.75, -42.4725], [19.75, -42.6566],
               [19.75, -42.8402], [19.75, -43.0232], [19.75, -43.2057],
               [19.75, -43.3877], [19.75, -43.5691], [19.75, -43.7499],
               [19.75, -43.9303], [19.75, -44.11], [19.75, -44.2893],
               [19.75, -44.4679], [19.75, -44.6461], [19.75, -44.8237],
               [19.75, -45.0007], [19.75, -45.1772], [19.75, -45.3532],
               [19.75, -45.5286], [19.75, -45.7035], [19.75, -45.8778],
               [19.75, -46.0515], [19.75, -46.2248], [19.75, -46.3975],
               [19.75, -46.5696], [19.75, -46.7412], [19.75, -46.9123],
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               [19.75, -47.591], [19.75, -47.7593], [19.75, -47.9271],
               [19.75, -48.0944], [19.75, -48.2611], [19.75, -48.4273],
               [19.75, -48.5929], [19.75, -48.758], [19.75, -48.9225],
               [19.75, -49.0865], [19.75, -49.25], [19.75, -49.4129],
               [19.75, -49.5753], [19.75, -49.7371], [19.75, -49.8984],
               [19.75, -50.0592], [19.75, -50.2194], [19.75, -50.3791],
               [19.75, -50.5383], [19.75, -50.6969], [19.75, -50.855],
               [19.75, -51.0125], [19.75, -51.1695], [19.75, -51.326],
               [19.75, -51.482], [19.75, -51.6374], [19.75, -51.7923],
               [19.75, -51.9467], [19.75, -52.1005], [19.75, -52.2538],
               [19.75, -52.4066], [19.75, -52.5588], [19.75, -52.7106],
               [19.75, -52.8618], [19.75, -53.0124], [19.75, -53.1626],
               [19.75, -53.3122], [19.75, -53.4613], [19.75, -53.6099],
               [19.75, -53.7579], [19.75, -53.9055], [19.75, -54.0525],
               [19.75, -54.199], [19.75, -54.345], [19.75, -54.4905],
               [19.75, -54.6354], [19.75, -54.7799], [19.75, -54.9238],
               [19.5, -54.9238], [19.25, -54.9238], [19, -54.9238],
               [18.75, -54.9238], [18.5, -54.9238], [18.25, -54.9238],
               [18, -54.9238], [17.75, -54.9238], [17.5, -54.9238],
               [17.25, -54.9238], [17, -54.9238], [16.75, -54.9238],
               [16.5, -54.9238], [16.25, -54.9238], [16, -54.9238],
               [15.75, -54.9238], [15.5, -54.9238], [15.25, -54.9238],
               [15, -54.9238], [14.75, -54.9238], [14.5, -54.9238],
               [14.25, -54.9238], [14, -54.9238], [13.75, -54.9238],
               [13.5, -54.9238], [13.25, -54.9238], [13, -54.9238],
               [12.75, -54.9238], [12.5, -54.9238], [12.25, -54.9238],
               [12, -54.9238], [11.75, -54.9238], [11.5, -54.9238],
               [11.25, -54.9238], [11, -54.9238], [10.75, -54.9238],
               [10.5, -54.9238], [10.25, -54.9238], [10, -54.9238],
               [9.75, -54.9238], [9.5, -54.9238], [9.25, -54.9238],
               [9, -54.9238], [8.75, -54.9238], [8.5, -54.9238],
               [8.25, -54.9238], [8, -54.9238], [7.75, -54.9238],
               [7.5, -54.9238], [7.25, -54.9238], [7, -54.9238],
               [6.75, -54.9238], [6.5, -54.9238], [6.25, -54.9238],
               [6, -54.9238], [5.75, -54.9238], [5.5, -54.9238],
               [5.25, -54.9238], [5, -54.9238], [4.75, -54.9238],
               [4.5, -54.9238], [4.25, -54.9238], [4, -54.9238],
               [3.75, -54.9238], [3.5, -54.9238], [3.25, -54.9238],
               [3, -54.9238], [2.75, -54.9238], [2.5, -54.9238],
               [2.25, -54.9238], [2, -54.9238], [1.75, -54.9238],
               [1.5, -54.9238], [1.25, -54.9238], [1, -54.9238],
               [0.75, -54.9238], [0.5, -54.9238], [0.25, -54.9238],
               [-1.81899e-12, -54.9238], [-0.25, -54.9238], [-0.5, -54.9238],
               [-0.75, -54.9238], [-1, -54.9238], [-1.25, -54.9238],
               [-1.5, -54.9238], [-1.75, -54.9238], [-2, -54.9238],
               [-2.25, -54.9238], [-2.5, -54.9238], [-2.75, -54.9238],
               [-3, -54.9238], [-3.25, -54.9238], [-3.5, -54.9238],
               [-3.75, -54.9238], [-4, -54.9238], [-4.25, -54.9238],
               [-4.5, -54.9238], [-4.75, -54.9238], [-5, -54.9238],
               [-5.25, -54.9238], [-5.5, -54.9238], [-5.75, -54.9238],
               [-6, -54.9238], [-6.25, -54.9238], [-6.5, -54.9238],
               [-6.75, -54.9238], [-7, -54.9238], [-7.25, -54.9238],
               [-7.5, -54.9238], [-7.75, -54.9238], [-8, -54.9238],
               [-8.25, -54.9238], [-8.5, -54.9238], [-8.75, -54.9238],
               [-9, -54.9238], [-9.25, -54.9238], [-9.5, -54.9238],
               [-9.75, -54.9238], [-10, -54.9238], [-10.25, -54.9238],
               [-10.5, -54.9238], [-10.75, -54.9238], [-11, -54.9238],
               [-11.25, -54.9238], [-11.5, -54.9238], [-11.75, -54.9238],
               [-12, -54.9238], [-12.25, -54.9238], [-12.5, -54.9238],
               [-12.75, -54.9238], [-13, -54.9238], [-13.25, -54.9238],
               [-13.5, -54.9238], [-13.75, -54.9238], [-14, -54.9238],
               [-14.25, -54.9238], [-14.5, -54.9238], [-14.75, -54.9238],
               [-15, -54.9238], [-15.25, -54.9238], [-15.5, -54.9238],
               [-15.75, -54.9238], [-16, -54.9238], [-16.25, -54.9238],
               [-16.5, -54.9238], [-16.75, -54.9238], [-17, -54.9238],
               [-17.25, -54.9238], [-17.5, -54.9238], [-17.75, -54.9238],
               [-18, -54.9238], [-18.25, -54.9238], [-18.5, -54.9238],
               [-18.75, -54.9238], [-19, -54.9238], [-19.25, -54.9238],
               [-19.5, -54.9238], [-19.75, -54.9238], [-20, -54.9238],
               [-20.25, -54.9238], [-20.5, -54.9238], [-20.75, -54.9238],
               [-21, -54.9238], [-21.25, -54.9238], [-21.5, -54.9238],
               [-21.75, -54.9238], [-22, -54.9238], [-22.25, -54.9238],
               [-22.5, -54.9238], [-22.75, -54.9238], [-23, -54.9238],
               [-23.25, -54.9238], [-23.5, -54.9238], [-23.75, -54.9238],
               [-24, -54.9238], [-24.25, -54.9238], [-24.5, -54.9238],
               [-24.75, -54.9238], [-25, -54.9238], [-25.25, -54.9238],
               [-25.5, -54.9238], [-25.75, -54.9238], [-26, -54.9238],
               [-26.25, -54.9238], [-26.5, -54.9238], [-26.75, -54.9238],
               [-27, -54.9238], [-27.25, -54.9238], [-27.5, -54.9238],
               [-27.75, -54.9238], [-28, -54.9238], [-28.25, -54.9238],
               [-28.5, -54.9238], [-28.75, -54.9238], [-29, -54.9238],
               [-29.25, -54.9238], [-29.5, -54.9238], [-29.75, -54.9238],
               [-30, -54.9238], [-30.25, -54.9238], [-30.5, -54.9238],
               [-30.75, -54.9238], [-31, -54.9238], [-31.25, -54.9238],
               [-31.5, -54.9238], [-31.75, -54.9238], [-32, -54.9238],
               [-32.25, -54.9238], [-32.5, -54.9238], [-32.75, -54.9238],
               [-33, -54.9238], [-33.25, -54.9238], [-33.5, -54.9238],
               [-33.75, -54.9238], [-34, -54.9238], [-34.25, -54.9238],
               [-34.5, -54.9238], [-34.75, -54.9238], [-35, -54.9238],
               [-35.25, -54.9238], [-35.5, -54.9238], [-35.75, -54.9238],
               [-36, -54.9238], [-36.25, -54.9238]]
lon = numpy.arange(0, 360, 10)
lat = numpy.arange(-80, 90, 10)
mx, my = numpy.meshgrid(lon, lat)

Creates the polython

polygon = pyinterp.geodetic.Polygon(
    [pyinterp.geodetic.Point(*item) for item in coordinates])
mask = polygon.covered_by(mx.ravel(), my.ravel())
mask = mask.reshape(mx.shape)

Display of the selection.

fig = matplotlib.pyplot.figure(figsize=(10, 8))
ax = fig.add_subplot(111, projection=cartopy.crs.PlateCarree())
ax.add_feature(cartopy.feature.LAND)
ax.gridlines(draw_labels=True, dms=True, x_inline=False, y_inline=False)
ax.coastlines()
ax.scatter(mx.ravel(),
           my.ravel(),
           c=mask,
           cmap='bwr_r',
           transform=cartopy.crs.PlateCarree(),
           vmin=0,
           vmax=1)
fig.show()
ex geodetic

Crossover#

The class handle the calculation of the crossover between two lines. We initialize two lines corresponding to two half-orbits of a satellite.

lon1 = numpy.array([234.068292, 234.092812, 234.117362, 234.141943],
                   dtype=numpy.float64)
lat1 = numpy.array([-67.11689, -67.132143, -67.147393, -67.162639],
                   dtype=numpy.float64)
lon2 = numpy.array([234.061488, 234.086091, 234.110664, 234.135205],
                   dtype=numpy.float64)
lat2 = numpy.array([-67.183321, -67.168076, -67.152826, -67.137573],
                   dtype=numpy.float64)

We create the two lines and the crossover.

crossover = pyinterp.geodetic.Crossover(
    pyinterp.geodetic.LineString(lon1, lat1),
    pyinterp.geodetic.LineString(lon2, lat2))

We can check if there is a crossing between these two lines.

print(f'There is a crossover between these two lines: {crossover.exists()}')
There is a crossover between these two lines: True

We can get the crossing point.

coordinates = crossover.search()
assert coordinates is not None
print(f'The crossing point is: {coordinates}')
The crossing point is: (-125.882, -67.148)

It is possible to obtain the points on the two lines nearest to the crossing point.

nearest_indices = crossover.nearest(coordinates)
assert nearest_indices is not None
print('The nearest points on the line #1: ' +
      str(crossover.half_orbit_1[nearest_indices[0]]))
print('The nearest points on the line #2: ' +
      str(crossover.half_orbit_2[nearest_indices[1]]))
The nearest points on the line #1: (234.117, -67.1474)
The nearest points on the line #2: (234.111, -67.1528)

Finally, the information found is displayed to verify the data found.

fig = matplotlib.pyplot.figure(figsize=(10, 8))
ax = fig.add_subplot(111, projection=cartopy.crs.PlateCarree())
ax.add_feature(cartopy.feature.LAND)
ax.plot(lon1, lat1, '-o', color='red', transform=cartopy.crs.PlateCarree())
ax.plot(lon2, lat2, '-o', color='blue', transform=cartopy.crs.PlateCarree())
ax.plot(coordinates.lon,
        coordinates.lat,
        '-o',
        color='green',
        transform=cartopy.crs.PlateCarree())
ax.plot(lon1[nearest_indices[0]],
        lat1[nearest_indices[0]],
        'o',
        color='orange',
        transform=cartopy.crs.PlateCarree())
ax.plot(lon2[nearest_indices[1]],
        lat2[nearest_indices[1]],
        'o',
        color='orange',
        transform=cartopy.crs.PlateCarree())
ax.gridlines(draw_labels=True, dms=True, x_inline=False, y_inline=False)
ex geodetic
<cartopy.mpl.gridliner.Gridliner object at 0x7fc6afa23fd0>

Total running time of the script: ( 0 minutes 17.139 seconds)

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