mavproxy_anufireproject: add module for utilities useful to the project

Starts by adding a command which creates KML layers from JSON data downloaded from the ACT government website.

MAVProxy/modules/mavproxy_anufireproject/__init__.py

@@ -0,0 +1,188 @@
+'''
+Add functionality to help with the ANU Fire Project
+e.g. download data from ACT government website and create KML layers from same
+
+AP_FLAKE8_CLEAN
+
+'''
+
+import json
+import math
+import os
+import pathlib
+import time
+
+from MAVProxy.modules.lib import mp_module
+from MAVProxy.modules.lib import mp_util
+
+
+class ANUFireProject(mp_module.MPModule):
+    def __init__(self, mpstate):
+        super(ANUFireProject, self).__init__(mpstate, "anufireproject", "")
+
+        self.kml_module_initialised = False
+
+        # stores the directory into which our persistent state should
+        # be dropped:
+        self.dot_mavproxy_path = mp_util.dot_mavproxy("anufp")
+        pathlib.Path(self.dot_mavproxy_path).mkdir(parents=True, exist_ok=True)
+
+        self.add_command(
+            'anufp',
+            self.cmd,
+            "ANU FireProject utility functions",
+            ["<burnkml>", "<burnkml> (BURNID)"],
+        )
+
+        self.burn_data_url = 'https://services1.arcgis.com/E5n4f1VY84i0xSjy/arcgis/rest/services/Prescribed_Burns_Public/FeatureServer/0/query?f=json&where=1%3D1&spatialRel=esriSpatialRelIntersects&geometry=%7B%22xmin%22%3A16505903.50821903%2C%22ymin%22%3A-4198481.646243979%2C%22xmax%22%3A16627897.005362216%2C%22ymax%22%3A-4144822.852387765%2C%22spatialReference%22%3A%7B%22wkid%22%3A102100%7D%7D&geometryType=esriGeometryEnvelope&inSR=102100&outFields=BURN_NAME%2CBOP_ID%2CHECTARES%2CWORKS_DESCRIPTION%2CBURN_TIMEFRAME%2CESRI_OID&orderByFields=ESRI_OID%20ASC&outSR=102100'  # noqa
+
+        self.burn_json = None
+        self.burn_json_time = 0
+        self.burn_json_lifetime = 600  # seconds we cache the json for
+        self.burn_json_refresh_attempt_time = 0
+
+        try:
+            # try not to set one variable without setting the other here.
+            cache_path = self.burn_data_cache_path()
+            content = cache_path.read_bytes()
+            mtime = cache_path.stat().st_mtime
+            self.burn_json = content
+            self.burn_json_time = mtime
+        except FileNotFoundError:
+            pass
+
+    def burn_data_cache_path(self):
+        '''returns a pathlib object corresponding to the filepath where we
+        cache the downloaded burn JSON'''
+        return pathlib.Path(os.path.join(self.dot_mavproxy_path, "burn_json.txt"))
+
+    def usage(self):
+        '''returns usage string'''
+        return "Usage: anufp <burnkml (BURNID)>"
+
+    def cmd(self, args):
+        '''handle commands from stdin'''
+        if len(args) < 1:
+            print(self.usage())
+            return
+
+        if args[0] == "burnkml":
+            return self.cmd_burnkml(args[1:])
+
+        print(self.usage())
+
+    def get_burn_json_object(self):
+        '''returns a json object containing the burn data'''
+        self.ensure_burn_json()
+        return json.loads(self.burn_json)
+
+    def cmd_burnkml(self, args):
+        '''command to trigger creation of a KML layer from a burn ID (e.g. FB511)'''
+        kml = self.module('kmlread')
+        if kml is None:
+            self.message("Need kmlread module")
+            return
+
+        if len(args) != 1:
+            print(self.usage())
+            print("BURNID is usually of the form FBxxx e.g. FB511")
+            return
+        burn_name = args[0]
+
+        burn_json = self.get_burn_json_object()
+        if burn_json is None:
+            return
+
+        found_feature = None
+        seen_bops = []
+        for feature in burn_json["features"]:
+            bop_id = feature["attributes"]["BOP_ID"]
+            seen_bops.append(bop_id)
+            if bop_id == burn_name:
+                found_feature = feature
+                break
+        if found_feature is None:
+            self.message(f"Burn {burn_name} not found in downloaded JSON (found {seen_bops})")
+            return
+
+        if "geometry" not in feature:
+            self.message(f"geometry missing from feature {burn_name}")
+            return
+
+        rings = feature["geometry"]["rings"]
+
+        for ring in rings:
+            coordinates = []
+            for item in ring:
+                lat, lon = self.MetersToLatLon(item[0], item[1])
+                coordinates.append((lat, lon))
+
+        kml.add_polygon(burn_name, coordinates)
+
+        # from: https://gist.githubusercontent.com/maptiler/fddb5ce33ba995d5523de9afdf8ef118/raw/d7565390d2480bfed3c439df5826f1d9e4b41761/globalmaptiles.py  # noqa
+    def MetersToLatLon(self, mx, my):
+        "Converts XY point from Spherical Mercator EPSG:900913 to lat/lon in WGS84 Datum"
+        originShift = 2 * math.pi * 6378137 / 2.0
+        # 20037508.342789244
+
+        lon = (mx / originShift) * 180.0
+        lat = (my / originShift) * 180.0
+
+        lat = 180 / math.pi * (2 * math.atan(math.exp(lat * math.pi / 180.0)) - math.pi / 2.0)
+        return lat, lon
+
+    def should_refresh_burn_json(self):
+        '''returns true if we should download the data from the ACT government
+        website again'''
+        now = time.time()
+        if now - self.burn_json_refresh_attempt_time < 60:
+            return False
+
+        if self.burn_json is None:
+            return True
+
+        if now - self.burn_json_time > self.burn_json_lifetime:
+            return True
+
+        return False
+
+    def message(self, msg):
+        '''simply emit msg prefixed with an identifying string'''
+        print(f"anufp: {msg}")
+
+    def refresh_burn_json(self):
+        '''downloads content from ACT Government URL, caches it in the
+        filesystem'''
+        tstart = time.time()
+        self.message("Refreshing burn data JSON")
+        self.burn_json_refresh_attempt_time = tstart
+        content = mp_util.download_url(self.burn_data_url)
+        if content is None:
+            return
+        self.burn_json = content
+        tstop = time.time()
+        self.burn_json_time = tstop
+
+        # cache the data:
+        cache_path = self.burn_data_cache_path()
+        cache_path.write_bytes(content)
+
+        self.message(f"Refreshed burn data JSON ({tstop-tstart}s)")
+
+    def ensure_burn_json(self):
+        '''checks to see if we should refresh the JSON data, and does that if
+        required'''
+        if not self.should_refresh_burn_json():
+            return
+        self.refresh_burn_json()
+
+    def idle_task(self):
+        # download the burn JSON once at startup to avoid delay on
+        # first kml command.
+        if self.burn_json is None:
+            self.ensure_burn_json()
+
+
+def init(mpstate):
+    '''initialise module'''
+    return ANUFireProject(mpstate)

setup.py

@@ -76,6 +76,7 @@ def package_files(directory):
       license='GPLv3',
       packages=['MAVProxy',
                 'MAVProxy.modules',
+                'MAVProxy.modules.mavproxy_anufireproject',
                 'MAVProxy.modules.mavproxy_fieldcheck',
                 'MAVProxy.modules.mavproxy_map',
                 'MAVProxy.modules.mavproxy_mmap',