map-machine/roentgen/flinger.py
2020-09-13 21:52:42 +03:00

114 lines
3.6 KiB
Python

"""
Author: Sergey Vartanov (me@enzet.ru)
"""
import math
import numpy as np
from typing import Optional
def get_ratio(maximum, minimum, ratio: float = 1):
return (maximum[0] - minimum[0]) * ratio / (maximum[1] - minimum[1])
def map_(
value: float, current_min: float, current_max: float, target_min: float,
target_max: float):
"""
Map current value in bounds of current_min and current_max to bounds of
target_min and target_max.
"""
return \
target_min + (value - current_min) / (current_max - current_min) * \
(target_max - target_min)
class Geo:
def __init__(self, lat: float, lon: float):
self.lat: float = lat
self.lon: float = lon
def __getitem__(self, item) -> Optional[float]:
if item == 0:
return self.lon
if item == 1:
return self.lat
return None
def __add__(self, other: "Geo") -> "Geo":
return Geo(self.lat + other.lat, self.lon + other.lon)
def __sub__(self, other: "Geo") -> "Geo":
return Geo(self.lat - other.lat, self.lon - other.lon)
def __repr__(self) -> str:
return f"{self.lat}, {self.lon}"
class GeoFlinger:
def __init__(
self, minimum, maximum, target_minimum, target_maximum):
"""
:param minimum: minimum latitude and longitude
:param maximum: maximum latitude and longitude
:param target_minimum: minimum of the resulting image
:param target_maximum: maximum of the resulting image
"""
self.minimum = minimum
self.maximum = maximum
# Ratio is depended of latitude. It is always <= 1. In one latitude
# degree is always 40 000 / 360 km. In one current longitude degree is
# about 40 000 / 360 * ratio km.
ratio = math.sin(
(90.0 - ((self.maximum.lat + self.minimum.lat) / 2.0))
/ 180.0 * math.pi)
# Longitude displayed as x.
# Latitude displayed as y.
# Ratio is x / y.
space: np.array = [0, 0]
current_ratio = get_ratio(self.maximum, self.minimum, ratio)
target_ratio = get_ratio(target_maximum, target_minimum)
if current_ratio >= target_ratio:
n = (target_maximum[0] - target_minimum[0]) / \
(maximum.lon - minimum.lon) / ratio
space[1] = \
((target_maximum[1] - target_minimum[1]) -
(maximum.lat - minimum.lat) * n) / 2.0
space[0] = 0
else:
n = (target_maximum[1] - target_minimum[1]) / \
(maximum.lat - minimum.lat) * ratio
space[0] = \
((target_maximum[0] - target_minimum[0]) -
(maximum.lon - minimum.lon) * n) / 2.0
space[1] = 0
self.target_minimum = np.add(target_minimum, space)
self.target_maximum = np.subtract(target_maximum, space)
meters_per_pixel = \
(self.maximum.lat - self.minimum.lat) / \
(self.target_maximum[1] - self.target_minimum[1]) * \
40000 / 360 * 1000
self.scale = 1 / meters_per_pixel
self.space = space
def fling(self, current) -> np.array:
"""
:param current: vector to fling
"""
x = map_(
current.lon, self.minimum.lon, self.maximum.lon,
self.target_minimum[0], self.target_maximum[0])
y = map_(
self.maximum.lat + self.minimum.lat - current.lat,
self.minimum.lat, self.maximum.lat,
self.target_minimum[1], self.target_maximum[1])
return np.array([x, y])