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Merge pull request #258 from rstudio/airmass-example
Airmass example
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‎examples/airmass/app.py‎

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import datetime
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from typing import Dict, List, Optional, Tuple
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import astropy.units as u
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import matplotlib.dates as mpldates
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import matplotlib.pyplot as plt
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import numpy as np
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import pandas as pd
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import pytz
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import suntime
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import timezonefinder
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from astropy.coordinates import AltAz, EarthLocation, SkyCoord
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from shiny import App, Inputs, Outputs, Session, reactive, render, req, ui
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from location import location_server, location_ui
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app_ui = ui.page_fixed(
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ui.tags.h3("Air mass calculator"),
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ui.div(
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ui.markdown(
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"""This Shiny app uses [Astropy](https://www.astropy.org/) to calculate the
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altitude (degrees above the horizon) and airmass (the amount of atmospheric
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air along your line of sight to an object) of one or more astronomical
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objects, over a given evening, at a given geographic location.
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"""
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),
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class_="mb-5",
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),
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ui.row(
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ui.column(
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8,
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ui.output_ui("timeinfo"),
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ui.output_plot("plot", height="800px"),
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# For debugging
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# ui.output_table("table"),
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class_="order-2 order-sm-1",
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),
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ui.column(
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4,
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ui.panel_well(
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ui.input_date("date", "Date"),
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class_="pb-1 mb-3",
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),
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ui.panel_well(
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ui.input_text_area(
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"objects", "Target object(s)", "M1, NGC35, PLX299", rows=3
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),
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class_="pb-1 mb-3",
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),
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ui.panel_well(
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location_ui("location"),
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class_="mb-3",
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),
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class_="order-1 order-sm-2",
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),
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),
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)
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def server(input: Inputs, output: Outputs, session: Session):
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loc = location_server("location")
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time_padding = datetime.timedelta(hours=1.5)
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@reactive.Calc
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def obj_names() -> List[str]:
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"""Returns a split and *slightly* cleaned-up list of object names"""
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req(input.objects())
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return [x.strip() for x in input.objects().split(",") if x.strip() != ""]
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@reactive.Calc
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def obj_coords() -> List[SkyCoord]:
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return [SkyCoord.from_name(name) for name in obj_names()]
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@reactive.Calc
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def times_utc() -> Tuple[datetime.datetime, datetime.datetime]:
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req(input.date())
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lat, long = loc()
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sun = suntime.Sun(lat, long)
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return (
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sun.get_sunset_time(input.date()),
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sun.get_sunrise_time(input.date() + datetime.timedelta(days=1)),
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)
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@reactive.Calc
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def timezone() -> Optional[str]:
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lat, long = loc()
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return timezonefinder.TimezoneFinder().timezone_at(lat=lat, lng=long)
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@reactive.Calc
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def times_at_loc():
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start, end = times_utc()
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tz = pytz.timezone(timezone())
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return (start.astimezone(tz), end.astimezone(tz))
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@reactive.Calc
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def df() -> Dict[str, pd.DataFrame]:
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start, end = times_at_loc()
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times = pd.date_range(
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start - time_padding,
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end + time_padding,
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periods=100,
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)
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lat, long = loc()
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eloc = EarthLocation(lat=lat * u.deg, lon=long * u.deg, height=0)
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altaz_list = [
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obj.transform_to(AltAz(obstime=times, location=eloc))
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for obj in obj_coords()
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]
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return {
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obj: pd.DataFrame(
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{
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"obj": obj,
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"time": times,
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"alt": altaz.alt,
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# Filter out discontinuity
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"secz": np.where(altaz.alt > 0, altaz.secz, np.nan),
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}
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)
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for (altaz, obj) in zip(altaz_list, obj_names())
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}
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@output
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@render.plot
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def plot():
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fig, [ax1, ax2] = plt.subplots(nrows=2)
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sunset, sunrise = times_at_loc()
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def add_boundary(ax, xval):
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ax.axvline(x=xval, c="#888888", ls="dashed")
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ax1.set_ylabel("Altitude (deg)")
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ax1.set_xlabel("Time")
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ax1.set_ylim(-10, 90)
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ax1.set_xlim(sunset - time_padding, sunrise + time_padding)
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ax1.grid()
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add_boundary(ax1, sunset)
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add_boundary(ax1, sunrise)
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for obj_name, data in df().items():
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ax1.plot(data["time"], data["alt"], label=obj_name)
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ax1.xaxis.set_major_locator(mpldates.AutoDateLocator())
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ax1.xaxis.set_major_formatter(
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mpldates.DateFormatter("%H:%M", tz=pytz.timezone(timezone()))
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)
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ax1.legend(loc="upper right")
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ax2.set_ylabel("Air mass")
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ax2.set_xlabel("Time")
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ax2.set_ylim(4, 1)
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ax2.set_xlim(sunset - time_padding, sunrise + time_padding)
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ax2.grid()
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add_boundary(ax2, sunset)
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add_boundary(ax2, sunrise)
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for data in df().values():
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ax2.plot(data["time"], data["secz"])
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ax2.xaxis.set_major_locator(mpldates.AutoDateLocator())
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ax2.xaxis.set_major_formatter(
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mpldates.DateFormatter("%H:%M", tz=pytz.timezone(timezone()))
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)
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return fig
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@output
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@render.table
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def table() -> pd.DataFrame:
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return pd.concat(df())
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@output
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@render.ui
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def timeinfo():
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start_utc, end_utc = times_utc()
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start_at_loc, end_at_loc = times_at_loc()
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return ui.TagList(
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f"Sunset: {start_utc.strftime('%H:%M')}, ",
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f"Sunrise: {end_utc.strftime('%H:%M')} ",
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"(UTC)",
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ui.tags.br(),
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f"Sunset: {start_at_loc.strftime('%H:%M')}, ",
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f"Sunrise: {end_at_loc.strftime('%H:%M')} ",
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f"({timezone()})",
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)
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# The debug=True causes it to print messages to the console.
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app = App(app_ui, server, debug=False)

‎examples/airmass/location.py‎

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from typing import Optional
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import ipyleaflet as L
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from shiny import Inputs, Outputs, Session, module, reactive, req, ui
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from shinywidgets import output_widget, reactive_read, register_widget
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# ============================================================
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# Module: location
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# ============================================================
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@module.ui
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def location_ui(
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label: str = "Location",
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*,
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lat: Optional[float] = None,
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long: Optional[float] = None,
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) -> ui.TagChildArg:
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return ui.div(
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ui.input_numeric("lat", "Latitude", value=lat),
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ui.input_numeric("long", "Longitude", value=long),
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ui.help_text("Click to select location"),
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output_widget("map", height="200px"),
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ui.tags.style(
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"""
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.jupyter-widgets.leaflet-widgets {
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height: 100% !important;
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}
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"""
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),
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)
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@module.server
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def location_server(
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input: Inputs, output: Outputs, session: Session, *, wrap_long: bool = True
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):
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map = L.Map(center=(0, 0), zoom=1, scoll_wheel_zoom=True)
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with reactive.isolate():
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marker = L.Marker(location=(input.lat() or 0, input.long() or 0))
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with reactive.isolate(): # Use this to ensure we only execute one time
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if input.lat() is None and input.long() is None:
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ui.notification_show(
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"Searching for location...", duration=99999, id="searching"
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)
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ui.insert_ui(
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ui.tags.script(
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"""
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navigator.geolocation.getCurrentPosition(
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({coords}) => {
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const {latitude, longitude, altitude} = coords;
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Shiny.setInputValue("#HERE#", {latitude, longitude});
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},
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(err) => {
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Shiny.setInputValue("#HERE#", {latitude: 0, longitude: 0});
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},
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{maximumAge: Infinity, timeout: Infinity}
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)
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""".replace(
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"#HERE#", module.resolve_id("here")
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)
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),
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selector="body",
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where="beforeEnd",
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immediate=True,
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)
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@reactive.isolate()
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def update_text_inputs(lat: Optional[float], long: Optional[float]) -> None:
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req(lat is not None, long is not None)
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lat = round(lat, 8)
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long = round(long, 8)
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if lat != input.lat():
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input.lat.freeze()
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ui.update_text("lat", value=lat)
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if long != input.long():
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input.long.freeze()
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ui.update_text("long", value=long)
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map.center = (lat, long)
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@reactive.isolate()
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def update_marker(lat: Optional[float], long: Optional[float]) -> None:
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req(lat is not None, long is not None)
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lat = round(lat, 8)
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long = round(long, 8)
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if marker.location != (lat, long):
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marker.location = (lat, long)
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if marker not in map.layers:
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map.add_layer(marker)
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map.center = marker.location
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def on_map_interaction(**kwargs):
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if kwargs.get("type") == "click":
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lat, long = kwargs.get("coordinates")
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update_text_inputs(lat, long)
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map.on_interaction(on_map_interaction)
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register_widget("map", map)
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@reactive.Effect
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def _():
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coords = reactive_read(marker, "location")
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if coords:
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update_text_inputs(coords[0], coords[1])
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@reactive.Effect
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def sync_autolocate():
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coords = input.here()
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ui.notification_remove("searching")
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if coords and not input.lat() and not input.long():
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update_text_inputs(coords["latitude"], coords["longitude"])
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@reactive.Effect
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def sync_inputs_to_marker():
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update_marker(input.lat(), input.long())
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@reactive.Calc
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def location():
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"""Returns tuple of (lat,long) floats--or throws silent error if no lat/long is
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selected"""
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# Require lat/long to be populated before we can proceed
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req(input.lat() is not None, input.long() is not None)
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try:
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long = input.long()
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# Wrap longitudes so they're within [-180, 180]
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if wrap_long:
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long = (long + 180) % 360 - 180
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return (input.lat(), long)
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except ValueError:
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raise ValueError("Invalid latitude/longitude specification")
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return location

‎examples/airmass/requirements.in‎

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astropy
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ipyleaflet
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matplotlib
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numpy
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pandas
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pytz
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shiny
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shinywidgets
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suntime
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timezonefinder

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