def compute_tmerc_parameters(coordinates_file: Path,
terrain: str) -> TransverseMercator:
data = json.loads(coordinates_file.read_text())
airbases = load_coordinate_data(data)
wgs84 = CRS("WGS84")
# Creates a transformer with 0 for the false easting and northing, but otherwise has
# the correct parameters. We'll use this to transform the zero point from the
# mission to calculate the error from the actual zero point to determine the correct
# false easting and northing.
bad = TransverseMercator(
central_meridian=CENTRAL_MERIDIANS[terrain],
false_easting=0,
false_northing=0,
scale_factor=0.9996,
).to_crs()
zero_finder = Transformer.from_crs(wgs84, bad)
z, x = zero_finder.transform(airbases["zero"].latitude,
airbases["zero"].longitude)
parameters = TransverseMercator(
central_meridian=CENTRAL_MERIDIANS[terrain],
false_easting=-x,
false_northing=-z,
scale_factor=0.9996,
)
if test_parameters(airbases, parameters):
sys.exit("Found errors in projection parameters. Quitting.")
return parameters
def test_parameters(airbases: Dict[str, Coordinates],
parameters: TransverseMercator) -> bool:
errors = False
wgs84 = CRS("WGS84")
crs = parameters.to_crs()
lat_lon_to_x_z = Transformer.from_crs(wgs84, crs)
x_z_to_lat_lon = Transformer.from_crs(crs, wgs84)
for name, coords in airbases.items():
if name == "zero":
continue
if test_for_errors(name, lat_lon_to_x_z, x_z_to_lat_lon, coords):
errors = True
return errors
from game.theater.projections import TransverseMercator
PARAMETERS = TransverseMercator(
central_meridian=-3,
false_easting=-195526.00000000204,
false_northing=-5484812.999999951,
scale_factor=0.9996,
)
from game.theater.projections import TransverseMercator
PARAMETERS = TransverseMercator(
central_meridian=147,
false_easting=238417.99999989968,
false_northing=-1491840.000000048,
scale_factor=0.9996,
)
from game.theater.projections import TransverseMercator
PARAMETERS = TransverseMercator(
central_meridian=3,
false_easting=99376.00000000288,
false_northing=-5636889.00000001,
scale_factor=0.9996,
)
from game.theater.projections import TransverseMercator
PARAMETERS = TransverseMercator(
central_meridian=57,
false_easting=75755.99999999645,
false_northing=-2894933.0000000377,
scale_factor=0.9996,
)
from game.theater.projections import TransverseMercator
PARAMETERS = TransverseMercator(
central_meridian=33,
false_easting=-99516.9999999732,
false_northing=-4998114.999999984,
scale_factor=0.9996,
)
from game.theater.projections import TransverseMercator
PARAMETERS = TransverseMercator(
central_meridian=-117,
false_easting=-193996.80999964548,
false_northing=-4410028.063999966,
scale_factor=0.9996,
)
from game.theater.projections import TransverseMercator
PARAMETERS = TransverseMercator(
central_meridian=39,
false_easting=282801.00000003993,
false_northing=-3879865.9999999935,
scale_factor=0.9996,
)