Add script to get SNOs for two platforms

.gitignore

@@ -13,7 +13,6 @@ dist
 build
 eggs
 parts
-bin
 var
 sdist
 develop-eggs

.pre-commit-config.yaml

@@ -0,0 +1,8 @@
+exclude: '^$'
+fail_fast: false
+repos:
+-   repo: https://github.com/pre-commit/pre-commit-hooks
+    rev: v2.2.3
+    hooks:
+    - id: flake8
+      additional_dependencies: [flake8-docstrings, flake8-debugger, flake8-bugbear]

bin/get_snos.py

@@ -0,0 +1,171 @@
+#!/usr/bin/env python
+# -*- coding: utf-8 -*-
+
+# Copyright (c) 2014 - 2019 Adam.Dybbroe
+
+# Author(s):
+
+#   Adam.Dybbroe <[email protected]>
+#   Nina Håkansson <[email protected]>
+#   Erik Johansson <[email protected]>
+
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+
+# You should have received a copy of the GNU General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+"""Getting SNOs for two configurable satellite platforms.
+
+SNO = Simultaneous Nadir Overpass: When two platforms sub-satellite track nadir
+views cross each other in space and time. One can set a threshold in time
+allowing the times to differ by up to a few minutes.
+
+"""
+
+import sys
+from datetime import datetime, timedelta
+
+from pyorbital.orbital import Orbital
+from pyorbital.sno_utils import get_config
+from pyorbital.sno_utils import get_arc
+from pyorbital.sno_utils import get_tle
+from pyorbital.sno_utils import get_sno_point
+import logging
+
+LOG = logging.getLogger('snos')
+
+handler = logging.StreamHandler(sys.stderr)
+handler.setLevel(0)
+LOG.setLevel(0)
+LOG.addHandler(handler)
+
+
+def get_arguments():
+    """Get the comman line arguments required to run the script."""
+    import argparse
+
+    parser = argparse.ArgumentParser(description='Calculate SNOS between two satellite platforms')
+    parser.add_argument("-s", "--start-datetime",
+                        required=True,
+                        dest="start_datetime",
+                        type=str,
+                        default=None,
+                        help="The datetime string corresponding to the start time of when SNOS should be calculated")
+    parser.add_argument("-e", "--end-datetime",
+                        required=True,
+                        dest="end_datetime",
+                        type=str,
+                        default=None,
+                        help="The datetime string corresponding to the end time of when SNOS should be calculated")
+    parser.add_argument("-t", "--time-window",
+                        required=True,
+                        dest="time_window",
+                        type=str,
+                        default=None,
+                        help=("The time window in number of minutes - the maximum time allowed between " +
+                              "the two SNO observations"))
+    parser.add_argument("-p", "--platform-name",
+                        required=True,
+                        dest="platform_name",
+                        type=str,
+                        default=None,
+                        help="The name of the satellite platform")
+    parser.add_argument("-c", "--configfile",
+                        required=True,
+                        dest="configfile",
+                        type=str,
+                        default=None,
+                        help="The path to the configuration file")
+    parser.add_argument("-l", "--log-file", dest="log",
+                        type=str,
+                        default=None,
+                        help="The file to log to (stdout per default).")
+
+    args = parser.parse_args()
+    return args
+
+
+def main():
+    """Find SNOs for the two platforms within the time period given."""
+    args = get_arguments()
+    conf = get_config(args.configfile)
+
+    station = {}
+    station['lon'] = conf['station']['longitude']
+    station['lat'] = conf['station']['latitude']
+    station['alt'] = conf['station']['altitude']
+
+    ref_platform_name = conf['reference_platform']['name']
+
+    tle_dirs = conf['tle-dirs']
+    tle_file_format = conf['tle-file-format']
+    platform_id = args.platform_name
+    minthr = int(args.time_window)
+    time_start = datetime.strptime(args.start_datetime, "%Y%m%d")
+    time_end = datetime.strptime(args.end_datetime, "%Y%m%d")
+
+    dtime = timedelta(seconds=60 * minthr * 2.0)
+    timestep = timedelta(seconds=60 * minthr * 1.0)
+    delta_t = dtime
+
+    tobj = time_start
+    tle_ref_pltfrm = None
+    tle_cmp_platform = None
+    tobj_tmp = time_start
+    while tobj < time_end:
+        if not tle_ref_pltfrm or abs(tle_ref_pltfrm.epoch.astype(datetime) - tobj) > timedelta(days=1):
+            tle_ref_pltfrm = get_tle(tle_dirs, tle_file_format, ref_platform_name, tobj)
+        if (not tle_cmp_platform or
+                abs(tle_cmp_platform.epoch.astype(datetime) - tobj) > timedelta(days=2)):
+            tle_cmp_platform = get_tle(tle_dirs, tle_file_format, platform_id, tobj)
+
+        ref_pltfrm = Orbital(ref_platform_name,
+                             line1=tle_ref_pltfrm.line1,
+                             line2=tle_ref_pltfrm.line2)
+        cmp_platform = Orbital(platform_id,
+                               line1=tle_cmp_platform.line1,
+                               line2=tle_cmp_platform.line2)
+
+        arc_ref_pltfrm = get_arc(tobj, timestep, ref_pltfrm)
+        arc_cmp_platform = get_arc(tobj, timestep, cmp_platform)
+
+        if arc_ref_pltfrm and arc_cmp_platform:
+            if arc_ref_pltfrm.intersects(arc_cmp_platform):
+                # If the two sub-satellite tracks of the overpasses intersects
+                # get the sub-satellite position and time where they cross,
+                # and determine if the time deviation is smaller than the require threshold:
+                sno = get_sno_point(platform_id, cmp_platform, ref_pltfrm,
+                                    tobj, delta_t, arc_ref_pltfrm,
+                                    arc_cmp_platform, station, minthr)
+
+                if sno:
+                    print("  " +
+                          str(sno['maxt_ref_pltfrm'].strftime("%Y-%m-%d %H:%M, ")) +
+                          "%5.1f," % sno['ref_pltfrmsec'] + " "*5 +
+                          str(sno['maxt'].strftime("%Y-%m-%d %H:%M, ")) +
+                          "%5.1f," % sno['sec'] +
+                          # " imager-orbit, %d, " % (sno['orbit_nr'] + 1) +
+                          " %d, " % (sno['orbit_nr'] + 1) +
+                          " "*6 + "%7.2f,  %7.2f," % (sno['point'][1], sno['point'][0]) +
+                          "   " + "%4.1f," % abs(sno['tdmin']) + "   " + str(sno['is_within_antenna_horizon'])
+                          )
+
+        else:
+            LOG.error("Failed getting the track-segments")
+
+        tobj = tobj + dtime
+        if tobj - tobj_tmp > timedelta(days=1):
+            tobj_tmp = tobj
+            LOG.debug(tobj_tmp.strftime("%Y-%m-%d"))
+
+
+if __name__ == "__main__":
+    main()

doc/source/api.rst

@@ -0,0 +1,30 @@
+The :mod:`pyorbital` API
+=========================
+
+Orbital computations
+~~~~~~~~~~~~~~~~~~~~
+
+.. automodule:: pyorbital.orbital
+   :members:
+   :undoc-members:
+
+TLE handling
+~~~~~~~~~~~~
+
+.. automodule:: pyorbital.tlefile
+   :members:
+   :undoc-members:
+
+Astronomical computations
+~~~~~~~~~~~~~~~~~~~~~~~~~
+
+.. automodule:: pyorbital.astronomy
+   :members:
+   :undoc-members:
+
+Simultaneous Nadir Overpass computations
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+.. automodule:: pyorbital.sno_utils
+   :members:
+   :undoc-members:

doc/source/astronomy.rst

@@ -0,0 +1,11 @@
+Computing astronomical parameters
+---------------------------------
+The astronomy module enables computation of certain parameters of interest for satellite remote sensing for instance the Sun-zenith angle:
+
+    >>> from pyorbital import astronomy
+    >>> from datetime import datetime
+    >>> utc_time = datetime(2012, 5, 15, 15, 45)
+    >>> lon, lat = 12, 56
+    >>> astronomy.sun_zenith_angle(utc_time, lon, lat)
+    62.685986438071602
+

doc/source/index.rst

@@ -3,117 +3,27 @@
    You can adapt this file completely to your liking, but it should at least
    contain the root `toctree` directive.
 
-Pyorbital
-=========
+====================================   
+Welcome to Pyorbital's documentation
+====================================
 
 Pyorbital is a python package to compute orbital parameters for satellites from
 TLE files as well as astronomical parameters of interest for satellite remote sensing.
 Currently pyorbital only supports low earth orbit satellites.
 
-Installation
-------------
-Pyorbital comes with a file platforms.txt that maps satellite name to NORAD identifier.
-This file needs to be copied to the appropriate satpy etc directory ($PPP_CONFIG_DIR).
-It is wise to check it contains your satellites of interest. The NORAD identifier can
-be found as the first number of each line in the Two-Line Elements (eg. from celestrak).
-
-TLE files
----------
-Pyorbital has a module for parsing NORAD TLE-files
-
-    >>> from pyorbital import tlefile
-    >>> tle = tlefile.read('noaa 18', '/path/to/my/tle_file.txt')
-    >>> tle.inclination
-    99.043499999999995
-
-If no path is given pyorbital tries to read the earth observation TLE-files from celestrak.com
-
-Computing satellite position
-----------------------------
-The orbital module enables computation of satellite position and velocity at a specific time:
-
-    >>> from pyorbital.orbital import Orbital
-    >>> from datetime import datetime
-    >>> # Use current TLEs from the internet:
-    >>> orb = Orbital("Suomi NPP")
-    >>> now = datetime.utcnow()
-    >>> # Get normalized position and velocity of the satellite:
-    >>> orb.get_position(now)
-    (array([-0.20015267,  0.09001458,  1.10686756]),
-     array([ 0.06148495,  0.03234914,  0.00846805]))
-    >>> # Get longitude, latitude and altitude of the satellite:
-    >>> orb.get_lonlatalt(now)
-    (40.374855865574951, 78.849923885700363, 839.62504115338368)
-
-
-Use actual TLEs to increase accuracy
-------------------------------------
-
-    >>> from pyorbital.orbital import Orbital
-    >>> from datetime import datetime
-    >>> orb = Orbital("Suomi NPP")
-    >>> dtobj = datetime(2015,2,7,3,0)
-    >>> orb.get_lonlatalt(dtobj)
-    (152.11564698762811, 20.475251739329622, 829.37355785502211)
-
-But since we are interested in knowing the position of the Suomi-NPP more than
-two and half years from now (September 26, 2017) we can not rely on the current
-TLEs, but rather need a TLE closer to the time of interest:
-
-    >>> snpp = Orbital('Suomi NPP', tle_file='/data/lang/satellit/polar/orbital_elements/TLE/201502/tle-20150207.txt')
-    >>> snpp.get_lonlatalt(dtobj)
-    (105.37373804512762, 79.160752404540133, 838.94605490133154)
-
-If we take a TLE from one week earlier we get a slightly different result:
-
-    >>> snpp = Orbital('Suomi NPP', tle_file='/data/lang/satellit/polar/orbital_elements/TLE/201501/tle-20150131.txt')
-    >>> snpp.get_lonlatalt(dtobj)
-    (104.1539184988462, 79.328272480878141, 838.81555967963391)
-
-
-
-Computing astronomical parameters
----------------------------------
-The astronomy module enables computation of certain parameters of interest for satellite remote sensing for instance the Sun-zenith angle:
-
-    >>> from pyorbital import astronomy
-    >>> from datetime import datetime
-    >>> utc_time = datetime(2012, 5, 15, 15, 45)
-    >>> lon, lat = 12, 56
-    >>> astronomy.sun_zenith_angle(utc_time, lon, lat)
-    62.685986438071602
-
-API
----
-
-Orbital computations
-~~~~~~~~~~~~~~~~~~~~
-
-.. automodule:: pyorbital.orbital
-   :members:
-   :undoc-members:
-
-TLE handling
-~~~~~~~~~~~~
-
-.. automodule:: pyorbital.tlefile
-   :members:
-   :undoc-members:
-
-Astronomical computations
-~~~~~~~~~~~~~~~~~~~~~~~~~
-
-.. automodule:: pyorbital.astronomy
-   :members:
-   :undoc-members:
-
-
-.. Contents:
-   .. toctree::
-      :maxdepth: 2
-   Indices and tables
-   ==================
-   * :ref:`genindex`
-   * :ref:`modindex`
-   * :ref:`search`
+.. toctree::
+   :maxdepth: 2
+
+   install
+   tlefiles
+   sat_position
+   astronomy
+   snos
+   api
+
+Indices and tables
+==================
+* :ref:`genindex`
+* :ref:`modindex`
+* :ref:`search`