Add coincident observations

CHANGELOG.md

@@ -12,6 +12,7 @@ Added:
  - Module `preprocess` to derive inputs from external datasets, including terrain masks from Copernicus DEM data (`compute_terrain_mask`, `compute_terrain_mask_for_station`, `compute_terrain_mask_for_platform`, `get_copernicus_dem_tile_urls`, and `sample_dem_elevation`, with an `effective_earth_radius_factor` for refraction, also an argument of `compute_terrain_elevation_angle`), and gridded weights from GeoTIFF rasters (`read_raster_weights`).
  - Generation method `generate_points_random` for random points, uniform by area or weighted by a raster (for example, of population counts or densities), optionally within a mask, with a seed for reproducibility.
  - Analysis methods `collect_region_observations` and `collect_multi_region_observations` to collect the periods (start and end) when an instrument observes any part of a region (shapely `Polygon` or `MultiPolygon`), using the footprints of pointed and conical instruments and the field of regard of other instruments. Each observation records its swath (the part of the region swept by the footprint) as its geometry and identifies the region by the hash of its geometry (`target_hash`). Methods `aggregate_observations` and `reduce_observations` combine the swaths of a region into the part of it observed.
+ - Analysis methods `find_coincident_observations`, the periods when two or more satellites observe the same point at once (or within a maximum time difference), and `find_coincident_ground_track`, the overlapping footprints of pairs of satellites at the same time (or within a maximum time difference), with example notebook `FindCoincidentObservations` (Metop-SG-B ICI and NASA FALCON).
  - Analysis methods `compute_access_periods`, the periods when a satellite is in view of a point above a minimum elevation angle, and `compute_region_access_periods`, a conservative superset of the periods when an instrument's field of regard may observe any part of a region (for example, to cull analysis times).
  - Support for shapely `Point` objects (longitude, latitude, and optional elevation) wherever a TAT-C `Point` is accepted (`collect_observations`, `collect_multi_observations`, `compute_dop`, and `GeneralPerturbationsOrbit.get_observation_events`), in anticipation of replacing TAT-C points.
  - Object schema `ConicalInstrument` (included in `AllInstruments`) for conically scanning instruments, observed when a point crosses the scanned cone, and utility method `compute_cone_and_azimuth`.

docs/api_reference/analysis/coincidence.rst

@@ -0,0 +1,10 @@
+Coincident Observations
+=======================
+
+Find Coincident Observations
+----------------------------
+.. autofunction:: tatc.analysis.find_coincident_observations
+
+Find Coincident Ground Track
+----------------------------
+.. autofunction:: tatc.analysis.find_coincident_ground_track

docs/api_reference/analysis/index.rst

@@ -9,6 +9,7 @@ Analysis functions simulate mission operation to compute key performance metrics
 
   coverage
   track
+  coincidence
   latency
   dop
   ro_coverage