Berlin to Oslo to Paris

Introduction to GeoPoint and GeoVector3D.

import matplotlib
matplotlib.rcParams['savefig.dpi'] = 300
import geonum

Create some GeoPoints

GeoPoints represent locations on Earth specified via latitude, longtitude and altitude relative sea level. Here we create 2, points, one located in Paris, one in Oslo, and one in Berlin. The latitudes and longitudes for each city were looked up online, the altitudes can be retrieved automatically using the SRTM dataset, as shown below.

paris = geonum.GeoPoint(name='Paris',
                        latitude=48.8566,
                        longitude=2.3522,
                        auto_topo_access=True
                        )

Retrieving SRTM data (this might take a while) ...
Creating /home/docs/.cache/srtm
4 2884802

print(paris)

GeoPoint Paris
Lat: 48.8566,  Lon: 2.3522000000000105, Alt: 46.0 m

oslo = geonum.GeoPoint(name='Oslo',
                       latitude=59.9139,
                       longitude=10.7522,
                       auto_topo_access=True
                       )

Retrieving SRTM data (this might take a while) ...
4 2884802

print(oslo)

GeoPoint Oslo
Lat: 59.9139,  Lon: 10.752199999999988, Alt: 26.0 m

berlin = geonum.GeoPoint(name='Berlin',
                       latitude=52.5200,
                       longitude=13.4050,
                       auto_topo_access=True
                       )

Retrieving SRTM data (this might take a while) ...
4 2884802

print(berlin)

GeoPoint Berlin
Lat: 52.52,  Lon: 13.405000000000001, Alt: 54.0 m

Compute connection vectors between the 3 locations

The connection vectors (dlat, dlon, dh) can be computed by subtracting 2 GeoPoint instances.

paris_to_berlin = berlin - paris
print(paris_to_berlin)

berlin_to_oslo = oslo - berlin
print(berlin_to_oslo)

oslo_to_paris = paris - oslo
print(oslo_to_paris)

# Assign the corresponding starting points for the vectors
paris_to_berlin.set_anchor(paris)
berlin_to_oslo.set_anchor(berlin)
oslo_to_paris.set_anchor(oslo)

GeoVector3D Paris->Berlin
Azimuth: 58.24°, Elevation: 0.0005°, Magnitude: 879.70 km (hor: 879.70 km)
GeoVector3D Berlin->Oslo
Azimuth: -10.21°, Elevation: -0.0019°, Magnitude: 839.39 km (hor: 839.39 km)
GeoVector3D Oslo->Paris
Azimuth: -152.59°, Elevation: 0.0009°, Magnitude: 1343.87 km (hor: 1343.87 km)

Draw map of western Europe and add points and vectors

import cartopy.feature as cfeature
from cartopy import crs
import matplotlib.pyplot as plt

# Init map with lat lon range
ax = geonum.plot_helpers.init_figure_with_geoaxes(xlim=(0, 20),
                                                  ylim=(45, 65))

# Add some features to make it look nicer
ax.coastlines(alpha=0.3)
ax.add_feature(cfeature.LAND, color='#fff9e6', alpha=0.4)
ax.add_feature(cfeature.OCEAN, color='#e6f7ff', alpha=0.4)
ax.add_feature(cfeature.BORDERS, color='#808080', ls='--', alpha=0.4)

# Plot paris GeoPoint into map
ax = geonum.plot_helpers.plot_geopoint_into_map(
    ax, paris,
    annotate=True,
    marker='o', facecolor='none',
    color='#5c5c3d',
    annot_kwargs=dict(xytext=(paris.longitude, paris.latitude-2),
                      ha='center'))

# Plot oslo GeoPoint into map
ax = geonum.plot_helpers.plot_geopoint_into_map(
    ax, oslo,
    annotate=True,
    marker='o', facecolor='none',
    color='#5c5c3d',
    annot_kwargs=dict(xytext=(oslo.longitude, oslo.latitude+1.5),
                      ha='center')
)

# Plot berlin GeoPoint into map
ax = geonum.plot_helpers.plot_geopoint_into_map(
    ax, berlin,
    annotate=True,
    marker='o', facecolor='none',
    color='#5c5c3d',
    annot_kwargs=dict(xytext=(berlin.longitude, berlin.latitude-1.5),
                      ha='center')
)

# Draw GeoVector3D Oslo->Paris into map
ax = geonum.plot_helpers.plot_geovector3d_into_map(ax, oslo_to_paris,
                                                   color='#5c5c3d',
                                                   ls='--', lw=1)

# annotate text specifying distance between points:
half_way_vec = oslo_to_paris/2
half_way = oslo + half_way_vec

# distance between Oslo and Paris
distance = oslo_to_paris.dist_hor
ax.annotate(text=f'Oslo/Paris:\n {distance:.0f} km',
            xy=(half_way.longitude, half_way.latitude),
            xytext=(half_way.longitude-1.5, half_way.latitude+1),
            color='#5c5c3d', fontweight='bold', ha='left', fontsize=6)

# Draw GeoVector3D Paris->Berlin into map
ax = geonum.plot_helpers.plot_geovector3d_into_map(ax, paris_to_berlin,
                                                   color='#5c5c3d',
                                                   ls='--', lw=1)

half_way_vec = paris_to_berlin/2
half_way = paris + half_way_vec
distance = paris_to_berlin.dist_hor
ax.annotate(text=f'Paris/Berlin:\n {distance:.0f} km',
            xy=(half_way.longitude, half_way.latitude),
            xytext=(half_way.longitude+2, half_way.latitude-1),
            color='#5c5c3d', fontweight='bold', ha='center', fontsize=6)

# Draw GeoVector3D Berlin->Oslo into map
ax = geonum.plot_helpers.plot_geovector3d_into_map(ax, berlin_to_oslo,
                                                   color='#5c5c3d',
                                                   ls='--', lw=1)

half_way_vec = berlin_to_oslo/2
half_way = berlin + half_way_vec
distance = berlin_to_oslo.dist_hor
ax.annotate(text=f'Berlin/Oslo:\n {distance:.0f} km',
            xy=(half_way.longitude, half_way.latitude),
            xytext=(half_way.longitude+1, half_way.latitude+1.8),
            color='#5c5c3d', fontweight='bold', ha='center', fontsize=6)

# Add x and y ticks
geonum.plot_helpers.set_map_ticks(ax)

# Add title
ax.set_title('Berlin to Oslo to Paris')

plt.show()

/home/docs/checkouts/readthedocs.org/user_builds/geonum/envs/latest/lib/python3.9/site-packages/cartopy/mpl/feature_artist.py:144: UserWarning: facecolor will have no effect as it has been defined as "never".
  warnings.warn('facecolor will have no effect as it has been '