xmet/lib/xmet/hodograph.py

249 lines
6.9 KiB
Python

import math
import cairo
from xmet.igra import IGRAReader
from xmet.sounding import Sounding
WIND_SPEED_MAX = 140 # knots
WIND_SPEED_MIN = 10
WIND_SPEED_STEP = 10
WIND_DIR_STEP = 90 # degrees
def radians(degrees: float) -> float:
return (degrees + 90) * (math.pi / 180.0)
def degrees(radians: float) -> float:
return (radians * (180.0 / math.pi)) - 90
def knots(ms: float) -> float:
return ms * 1.944
class Hodograph():
def __init__(self, width, height):
self.zoom = 1.2
self.offset_x = 0.1 # Percentage of the upper left quadrant rendered
self.offset_y = 0.9 # Percentage of the upper right quadrant rendered
self.min_x = 0
self.min_y = 0
self.max_x = 0
self.max_y = 0
self.width = min(width, height)
self.height = min(width, height)
self.radius = min(width, height) * self.zoom
def sample_to_graph(self, wind_speed: dir, wind_dir: float) -> tuple:
r = self.radius * (wind_speed / WIND_SPEED_MAX)
x = r * math.cos(radians(wind_dir))
y = r * math.sin(radians(wind_dir))
return x, y
def sample_to_screen(self, wind_speed: dir, wind_dir: float) -> tuple:
gx, gy = self.sample_to_graph(wind_speed, wind_dir)
return (
self.offset_x * self.width + gx,
self.offset_y * self.height + gy
)
def find_extents(self, sounding: Sounding):
"""
Determine the boundaries of the sounding to set the center and zoom
appropriately.
"""
for sample in sounding.samples:
x, y = self.sample_to_graph(sample.wind_speed, sample.wind_dir)
if self.min_x > x:
self.min_x = x
if self.min_y > y:
self.min_y = y
if self.max_x < x:
self.max_x = x
if self.max_y < y:
self.max_y = y
self.offset_x = self.min_x / self.radius + 0.1
self.offset_y = (self.radius - self.max_y) / self.radius
self.zoom = min(self.width, self.height) / max(self.max_x - self.min_x,
self.max_y - self.min_y) / 2
self.radius = min(self.width, self.height) * self.zoom
def draw_speed_lines(self, cr: cairo.Context, x, y):
cr.save()
cr.set_source_rgb(0.5, 0.5, 0.5)
cr.set_line_width(0.5)
cr.set_dash([5, 5], 1)
for speed in range(WIND_SPEED_MIN, WIND_SPEED_MAX+1, WIND_SPEED_STEP):
cr.arc(x + self.offset_x * self.width,
y + self.offset_y * self.height,
self.radius * min(speed, WIND_SPEED_MAX) / WIND_SPEED_MAX,
0,
2*math.pi)
cr.stroke()
cr.restore()
def draw_direction_lines(self, cr: cairo.Context, x, y):
cr.save()
cr.set_source_rgb(0.5, 0.5, 0.5)
for angle in range(0, 360+1, WIND_DIR_STEP):
sx1, sy1 = self.sample_to_screen(WIND_SPEED_MAX, angle)
sx2, sy2 = self.sample_to_screen(WIND_SPEED_MAX, angle + 180)
cr.move_to(x + sx1, y + sy1)
cr.line_to(x + sx2, y + sy2)
cr.stroke()
cr.restore()
def draw_speed_legends(self, cr: cairo.Context, x, y):
cr.save()
x_offset_scale = 0.01190476
y_offset_scale = 0.01
x_offset = x_offset_scale * self.radius
y_offset = y_offset_scale * self.radius
for speed in range(WIND_SPEED_MIN, WIND_SPEED_MAX, WIND_SPEED_STEP):
text = "%dkt" % speed
extents = cr.text_extents(text)
sx, sy = self.sample_to_screen(speed, 180)
cr.move_to(x + sx + x_offset, y + sy - y_offset)
cr.show_text(text)
cr.stroke()
cr.restore()
COLORS = {
500: (1.0, 0.4, 1.0),
3000: (1.0, 0.4, 0.4),
7000: (0.4, 1.0, 0.4),
10000: (0.4, 0.4, 1.0)
}
def color(self, height: float):
for key in self.COLORS:
if height < key:
return self.COLORS[key]
def draw_sounding(self,
cr: cairo.Context,
x,
y,
sounding: Sounding):
cr.save()
first = True
color_last = None
sx_last = None
sy_last = None
for sample in sounding.samples:
if sample.pressure < 0 or sample.pressure is None:
continue
if sample.height is None:
continue
color = self.color(sample.height)
if color is None:
break
elif color is not color_last:
cr.stroke()
cr.set_source_rgb(*color)
if sx_last is not None and sy_last is not None:
cr.move_to(x + sx_last, x + sy_last)
sx, sy = self.sample_to_screen(knots(sample.wind_speed),
sample.wind_dir)
if first:
cr.move_to(x + sx, y + sy)
first = False
else:
cr.line_to(x + sx, y + sy)
color_last = color
sx_last = sx
sy_last = sy
cr.stroke()
cr.restore()
def draw_height_legends(self, cr: cairo.Context, x, y):
width = 0.02380952 * self.width
interval = 0.05952380 * self.width
offset = 0.75 * self.width
cr.save()
cr.set_source_rgb(1, 1, 1)
cr.rectangle(offset + x - width * 0.75,
y + width,
interval * 4,
width * 3)
cr.fill()
cr.set_source_rgb(0.8, 0.8, 0.8)
cr.rectangle(offset + x - width * 0.75,
y + width,
interval * 4,
width * 3)
cr.stroke()
cr.restore()
for height in self.COLORS:
color = self.COLORS[height]
cr.save()
cr.set_source_rgb(*color)
cr.rectangle(offset + x, y + width * 1.5, width, width)
cr.fill()
cr.restore()
cr.rectangle(offset + x, y + width * 1.5, width, width)
cr.stroke()
text = "%dm" % (height) if height < 1000 else "%dkm" % (height /1000)
extents = cr.text_extents(text)
cr.move_to(offset + x - extents.width / 4, y + 3.5*width)
cr.show_text(text)
cr.stroke()
offset += interval
def draw(self, cr: cairo.Context, x, y, sounding: Sounding):
self.find_extents(sounding)
cr.rectangle(x, y, self.width, self.height)
cr.clip()
self.draw_speed_lines(cr, x, y)
self.draw_direction_lines(cr, x, y)
self.draw_sounding(cr, x, y, sounding)
self.draw_speed_legends(cr, x, y)
self.draw_height_legends(cr, x, y)
cr.reset_clip()