Merge pull request #27 from astronomy-commons/issue/26/plot

Add method to plot a single light curve.

Author: delucchi-cmu

docs/notebooks/plot_light_curves.ipynb

@@ -16,7 +16,7 @@ classifiers = [
 dynamic = ["version"]
 requires-python = ">=3.10"
 dependencies = [
-    "lsdb>=0.5.0", # For catalog operations
+    "lsdb>=0.6.3", # For catalog operations
     "skymap-convert>=0.1.1", # For skymap-based methods, such as tract_patch_search
 ]
 

pyproject.toml

@@ -0,0 +1,162 @@
+import matplotlib.pyplot as plt
+import nested_pandas as npd
+
+plot_filter_colors_rainbow = {
+    "u": "#0c71ff",  # Blue
+    "g": "#49be61",  # Green
+    "r": "#ff0000",  # Red
+    "i": "#ffc200",  # Orange/Yellow
+    "z": "#f341a2",  # Pink/Magenta
+    "y": "#990099",  # Purple
+}
+
+## https://rtn-045.lsst.io/#colorblind-friendly-plots
+plot_filter_colors_white_background = {
+    "u": "#1600ea",
+    "g": "#31de1f",
+    "r": "#b52626",
+    "i": "#370201",
+    "z": "#ba52ff",
+    "y": "#61a2b3",
+}
+plot_filter_colors_black_background = {
+    "u": "#3eb7ff",
+    "g": "#30c39f",
+    "r": "#ff7e00",
+    "i": "#2af5ff",
+    "z": "#a7f9c1",
+    "y": "#fdc900",
+}
+
+plot_filter_symbols = {
+    "u": "o",  # Circle
+    "g": "^",  # Triangle up
+    "r": "s",  # Square
+    "i": "D",  # Diamond
+    "z": "v",  # Triangle down
+    "y": "X",  # X
+}
+
+plot_symbols = {"u": "o", "g": "^", "r": "v", "i": "s", "z": "*", "y": "p"}
+plot_linestyles_none = {
+    "u": None,
+    "g": None,
+    "r": None,
+    "i": None,
+    "z": None,
+    "y": None,
+}
+
+plot_linestyles = {
+    "u": "--",
+    "g": (0, (3, 1, 1, 1)),
+    "r": "-.",
+    "i": "-",
+    "z": (0, (3, 1, 1, 1, 1, 1)),
+    "y": ":",
+}
+
+band_names_ugrizy = ["u", "g", "r", "i", "z", "y"]
+band_names_lsst_ugrizy = ["LSST_u", "LSST_g", "LSST_r", "LSST_i", "LSST_z", "LSST_y"]
+
+
+def plot_light_curve(
+    lc: npd.NestedFrame,
+    title="LSST light curve",
+    mag_field="psfMag",
+    flux_field=None,
+    legend_kwargs=None,
+    band_names=None,
+    plot_kwargs=None,
+    filter_colors=None,
+    filter_symbols=None,
+    filter_linestyles=None,
+    period=None,
+    num_periods=1,
+    period_mjd0=None,
+):
+    """Convenience method to plot a single light curve's magnitude. The y-axis is
+    upside-down since magnitude is bananas.
+
+    If you want additional configuration, you may be better served creating your own plotting
+    function, as this is intended for quick inspection of individual lightcurves in HATS-formatted
+    data products.
+
+    Args:
+        lc (npd.NestedFrame): Light curve data a single nested dataframe.
+        title (str, optional): Title for the plot. Defaults to "LSST light curve".
+        mag_field (str, optional): Field name for magnitude values. Defaults to "psfMag".
+            If using magnitude, the y-axis will be inverted.
+        flux_field (str, optional): Field name for flux values.
+            If None, uses mag_field instead. Defaults to None.
+        legend_kwargs (dict, optional): Keyword arguments for plt.legend(). Defaults to None.
+        band_names (list, optional): List of band names to plot. Defaults to None (uses ugrizy).
+        plot_kwargs (dict, optional): Additional keyword arguments for plt.errorbar(). Defaults to None.
+        filter_colors (dict, optional): Mapping of band names to colors.
+            Defaults to plot_filter_colors_white_background.
+        filter_symbols (dict, optional): Mapping of band names to marker symbols.
+            Defaults to plot_symbols.
+        filter_linestyles (dict, optional): Mapping of band names to line styles.
+            Defaults to plot_linestyles_none.
+        period (float, optional): If provided, folds the time axis by this period (in days).
+            Defaults to None.
+        num_periods (int): Used to plot multiple full periods. Defaults to 1 (single period).
+        period_mjd0 (float, optional): The time of the start of the phase-folded light curve.
+            If not provided, we use the earliest ``midpointMjdTai`` value.
+
+    Returns:
+        None
+    """
+    # Let's first set values to defaults if they're not specified in kwargs.
+    if plot_kwargs is None:
+        plot_kwargs = {}
+    if filter_colors is None:
+        filter_colors = plot_filter_colors_white_background
+    if filter_symbols is None:
+        filter_symbols = plot_symbols
+    if filter_linestyles is None:
+        filter_linestyles = plot_linestyles_none
+
+    if legend_kwargs is None:
+        legend_kwargs = {}
+    if band_names is None:
+        band_names = band_names_ugrizy
+
+    is_mag = flux_field is None
+    brightness_field = flux_field or mag_field
+    brightness_err_field = f"{brightness_field}Err"
+    if period_mjd0 is None:
+        period_mjd0 = lc["midpointMjdTai"].min()
+
+    # Actually do the plot
+    for band in band_names:
+        data = lc.query(f"band == '{band}'")
+        if len(data) == 0:
+            continue
+        x_axis = data["midpointMjdTai"]
+        if period is not None:
+            x_axis = (x_axis - period_mjd0) / period % num_periods
+        plt.errorbar(
+            x_axis,
+            data[brightness_field],
+            yerr=data[brightness_err_field],
+            label=band,
+            linestyle=filter_linestyles[band],
+            fmt=filter_symbols[band],
+            color=filter_colors[band],
+            **plot_kwargs,
+        )
+
+    if is_mag:
+        plt.gca().invert_yaxis()
+
+    if period is None:
+        plt.xlabel("MJD")
+    else:
+        plt.xlabel("phase")
+        plt.xlim([0, num_periods])
+        title = title + f" (period = {period} d)"
+
+    plt.ylabel(brightness_field)
+    plt.title(title)
+    plt.legend(**legend_kwargs)

src/lsdb_rubin/plot_light_curve.py

@@ -0,0 +1,14 @@
+#HATS catalog
+obs_collection=mock_dp1_1000
+dataproduct_type=object
+hats_nrows=1000
+hats_col_ra=ra
+hats_col_dec=dec
+hats_npix_suffix=.parquet
+hats_skymap_order=8
+hats_max_rows=1000
+hats_builder=lsdb v0.6.4.dev2+gf79d1a04, hats v0.6.2
+hats_creation_date=2025-08-08T13\:53UTC
+hats_estsize=25358
+hats_release_date=2024-09-18
+hats_version=v0.1

tests/data/mock_dp1_1000/dataset/Norder=0/Dir=0/Npix=0.parquet

@@ -0,0 +1,2 @@
+Norder,Npix
+0,0