Define spatial bins for pset (#819)

* Define spatial bins for pset

imap_processing/tests/ultra/unit/test_ultra_l1c_pset_bins.py

@@ -2,7 +2,10 @@
 
 import numpy as np
 
-from imap_processing.ultra.l1c.ultra_l1c_pset_bins import build_energy_bins
+from imap_processing.ultra.l1c.ultra_l1c_pset_bins import (
+    build_energy_bins,
+    build_spatial_bins,
+)
 
 
 def test_build_energy_bins():
@@ -13,7 +16,20 @@ def test_build_energy_bins():
     assert len(energy_bin_start) == 90
     assert len(energy_bin_end) == 90
 
-    # Comparison to expected values
+    # Comparison to expected values.
     np.testing.assert_allclose(energy_bin_end[0], 3.6795, atol=1e-4)
     np.testing.assert_allclose(energy_bin_start[-1], 299.9724, atol=1e-4)
     np.testing.assert_allclose(energy_bin_end[-1], 315.3556, atol=1e-4)
+
+
+def test_build_spatial_bins():
+    """Tests build_spatial_bins function."""
+    az_bin_edges, el_bin_edges = build_spatial_bins()
+
+    assert az_bin_edges[0] == 0
+    assert az_bin_edges[-1] == 360
+    assert len(az_bin_edges) == 721
+
+    assert el_bin_edges[0] == -90
+    assert el_bin_edges[-1] == 90
+    assert len(el_bin_edges) == 361

imap_processing/ultra/l1c/ultra_l1c_pset_bins.py

@@ -1,4 +1,4 @@
-"""Module to create energy bins for pointing sets."""
+"""Module to create bins for pointing sets."""
 
 import numpy as np
 
@@ -27,3 +27,28 @@ def build_energy_bins() -> tuple[np.ndarray, np.ndarray]:
     energy_bin_end = bin_edges[1:]
 
     return energy_bin_start, energy_bin_end
+
+
+def build_spatial_bins(spacing: float = 0.5) -> tuple[np.ndarray, np.ndarray]:
+    """
+    Build spatial bin boundaries for azimuth and elevation.
+
+    Parameters
+    ----------
+    spacing : float, optional
+        The bin spacing in degrees (default is 0.5 degrees).
+
+    Returns
+    -------
+    az_bin_edges : np.ndarray
+        Array of azimuth bin boundary values.
+    el_bin_edges : np.ndarray
+        Array of elevation bin boundary values.
+    """
+    # Azimuth bins from 0 to 360 degrees.
+    az_bin_edges = np.arange(0, 360 + spacing, spacing)
+
+    # Elevation bins from -90 to 90 degrees.
+    el_bin_edges = np.arange(-90, 90 + spacing, spacing)
+
+    return az_bin_edges, el_bin_edges