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#!/usr/bin/env python3
# Use the proper idiom in the main module ...
# NOTE: See https://docs.python.org/3.11/library/multiprocessing.html#the-spawn-and-forkserver-start-methods
if __name__ == "__main__":
# Import standard modules ...
import os
# Import special modules ...
try:
import cartopy
cartopy.config.update(
{
"cache_dir" : os.path.expanduser("~/.local/share/cartopy_cache"),
}
)
except:
raise Exception("\"cartopy\" is not installed; run \"pip install --user Cartopy\"") from None
try:
import matplotlib
matplotlib.rcParams.update(
{
"backend" : "Agg", # NOTE: See https://matplotlib.org/stable/gallery/user_interfaces/canvasagg.html
"figure.dpi" : 300,
"figure.figsize" : (9.6, 7.2), # NOTE: See https://github.com/Guymer/misc/blob/main/README.md#matplotlib-figure-sizes
"font.size" : 8,
}
)
import matplotlib.pyplot
except:
raise Exception("\"matplotlib\" is not installed; run \"pip install --user matplotlib\"") from None
try:
import shapely
import shapely.geometry
import shapely.ops
except:
raise Exception("\"shapely\" is not installed; run \"pip install --user Shapely\"") from None
# Import my modules ...
try:
import fmc
except:
raise Exception("\"fmc\" is not installed; you need to have the Python module from https://github.com/Guymer/fmc located somewhere in your $PYTHONPATH") from None
try:
import pyguymer3
import pyguymer3.geo
import pyguymer3.image
except:
raise Exception("\"pyguymer3\" is not installed; you need to have the Python module from https://github.com/Guymer/PyGuymer3 located somewhere in your $PYTHONPATH") from None
# **************************************************************************
# Create short-hand for the colour map and define the nautical mile, number
# of angles and resolution ...
cmap = matplotlib.pyplot.get_cmap("jet")
nm = 1852.0 # [m/NM]
fill = 0.1 # [°]
nang = 361 # [#]
res = "10m"
simp = 0.01 # [°]
tol = 1.0e-10 # [°]
# Find file containing all the country shapes ...
sfile = cartopy.io.shapereader.natural_earth(
category = "cultural",
name = "admin_0_countries",
resolution = res,
)
# Create a list of tuples of territories ...
# NOTE: The first entry is the territory name and the second is the list of
# Natural Earth country names that make up the territory. The BAT has
# been ignored as it has restrictions on its use.
territories = [
("United Kingdom" , ["United Kingdom"] ),
("Akrotiri & Dhekelia" , ["Akrotiri", "Dhekelia"] ),
("Anguilla" , ["Anguilla"] ),
("Bermuda" , ["Bermuda"] ),
("Cayman Islands" , ["Cayman Is."] ),
("Falkland Islands" , ["Falkland Is."] ),
("Gibraltar" , ["Gibraltar"] ),
("South Georgia & the South Sandwich Islands", ["S. Geo. and the Is."] ),
("British Indian Ocean Territory" , ["Br. Indian Ocean Ter."]),
("Montserrat" , ["Montserrat"] ),
("Pitcairn Islands" , ["Pitcairn Is."] ),
("Saint Helena, Ascension & Tristan da Cunha", ["Saint Helena"] ),
("Turks and Caicos Islands" , ["Turks and Caicos Is."] ),
("British Virgin Islands" , ["British Virgin Is."] ),
]
# Create list of British polygons ...
polys = []
# Loop over records ...
for record in cartopy.io.shapereader.Reader(sfile).records():
# Create short-hand ...
neName = pyguymer3.geo.getRecordAttribute(record, "NAME")
# Skip this record if it is not for a territory in the list ...
skip = True
for territory, countries in territories:
if neName in countries:
skip = False
break
if skip:
continue
# Loop over Polygons and add them to the list ...
for poly in pyguymer3.geo.extract_polys(record.geometry):
# HACK: The Natural Earth polygons are sometimes so coarse that they
# do not cover the runway (e.g. Diego Garcia) so they are
# buffered by 5km.
polys += pyguymer3.geo.extract_polys(
pyguymer3.geo.buffer(
poly,
5000.0,
debug = False,
fill = fill,
nang = nang,
simp = simp,
tol = tol,
)
)
print(f"There are {len(polys):d} British polygons.")
# Create list of British airfields ...
# HACK: Manually add HLE as it is missing from the OpenFlights GitHub
# repository.
airfields = [] # [°], [°]
airfields.append(shapely.geometry.Point(-5.645833, -15.959167)) # [°], [°]
# Loop over airports ...
for airport in fmc.load_airport_list():
# Create point and check if it is within any of the polygons ...
airfield = shapely.geometry.Point(airport["Longitude"], airport["Latitude"])# [°], [°]
for poly in polys:
if poly.contains(airfield):
airfields.append(airfield) # [°], [°]
break
print(f"There are {len(airfields):d} British airfields.")
# Create figure ...
fg = matplotlib.pyplot.figure(figsize = (12.8, 7.2))
# Create axis ...
ax = fg.add_subplot(projection = cartopy.crs.Robinson())
# Configure axis ...
ax.set_global()
pyguymer3.geo.add_coastlines(ax)
pyguymer3.geo.add_map_background(ax, resolution = "large8192px")
pyguymer3.geo.add_horizontal_gridlines(
ax,
locs = range(-90, 135, 45),
)
pyguymer3.geo.add_vertical_gridlines(
ax,
locs = range(-180, 225, 45),
)
# Add country outlines ...
for record in cartopy.io.shapereader.Reader(sfile).records():
ax.add_geometries(
pyguymer3.geo.extract_polys(record.geometry),
cartopy.crs.PlateCarree(),
edgecolor = "black",
facecolor = "none",
linewidth = 0.5,
)
# Initialize distance, labels and lines ...
dist2 = 0.0 # [NM]
labels = []
lines = []
# Loop over distances ...
for i in range(8):
# Set distance ...
dist1 = 500.0 # [NM]
dist2 += dist1 # [NM]
# Decide what needs doing ...
if i == 0:
print(f"Calculating for {dist2:6,.0f} NM (using {len(airfields):,d} airfields) ...")
# Buffer airfields ...
# NOTE: "airfields" is the Point-list to be buffered.
geoms = []
for airfield in airfields:
geoms += pyguymer3.geo.extract_polys(
pyguymer3.geo.buffer(
airfield,
dist1 * nm,
debug = False,
fill = fill,
nang = nang,
simp = simp,
tol = tol,
)
)
geoms = shapely.ops.unary_union(geoms).simplify(tol)
pyguymer3.geo.check(geoms)
# NOTE: "geoms" is now the [Multi]Polygon buffer of "airfields".
else:
# Find out how complicated the [Multi]Polygon is ...
npoints = 0 # [#]
npolys = 0 # [#]
for poly in pyguymer3.geo.extract_polys(geoms):
npoints += len(poly.exterior.coords) # [#]
npolys += 1 # [#]
for interior in poly.interiors:
npoints += len(interior.coords) # [#]
print(f"Calculating for {dist2:6,.0f} NM (using {npoints:,d} points in {npolys:,d} Polygons) ...")
# Buffer area ...
# NOTE: "geoms" is the [Multi]Polygon to be buffered.
geoms = pyguymer3.geo.buffer(
geoms,
dist1 * nm,
debug = False,
fill = fill,
nang = nang,
simp = simp,
tol = tol,
)
# NOTE: "geoms" is now the [Multi]Polygon buffer of "geoms".
# Add to plot ...
ax.add_geometries(
pyguymer3.geo.extract_polys(geoms),
cartopy.crs.PlateCarree(),
edgecolor = cmap(float(i) / 7.0),
facecolor = "none",
linewidth = 1.0,
)
labels.append(f"{dist2:6,.0f} NM")
lines.append(matplotlib.lines.Line2D([], [], color = cmap(float(i) / 7.0)))
print("Plotting ...")
# Configure axis ...
ax.legend(
lines,
labels,
loc = "upper center",
ncol = 4,
)
# Configure figure ...
fg.tight_layout()
# Save figure ...
fg.savefig("find_airfields.png")
matplotlib.pyplot.close(fg)
# Optimize PNG ...
pyguymer3.image.optimize_image(
"find_airfields.png",
strip = True,
)
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