Merge pull request #196 from lsst/tickets/DM-47821

Add utility functions for consistent multiband plot colors

doc/changes/DM-47821.feature.rst

@@ -0,0 +1 @@
+Added ``lsst.utils.plotting.get_multiband_plot_colors``, ``lsst.utils.plotting.get_multiband_plot_linestyles``, and ``lsst.utils.plotting.get_multiband_plot_symbols`` utilities for making consistent multi-band plots.

python/lsst/utils/plotting/figures.py

@@ -12,9 +12,14 @@
 
 from __future__ import annotations
 
-__all__ = ["make_figure"]
+__all__ = [
+    "get_multiband_plot_colors",
+    "get_multiband_plot_symbols",
+    "get_multiband_plot_linestyles",
+    "make_figure",
+]
 
-from typing import TYPE_CHECKING, Any
+from typing import TYPE_CHECKING, Any, Dict
 
 if TYPE_CHECKING:
     from matplotlib.figure import Figure
@@ -55,3 +60,89 @@ def make_figure(**kwargs: Any) -> Figure:
     FigureCanvasAgg(fig)
 
     return fig
+
+
+def get_multiband_plot_colors(dark_background: bool = False) -> Dict:
+    """Get color mappings for multiband plots using SDSS filter names.
+
+    Notes
+    -----
+    From https://rtn-045.lsst.io/#colorblind-friendly-plots
+
+    Parameters
+    ----------
+    dark_background : `bool`, optional
+        Use colors intended for a dark background.
+        Default colors are intended for a light background.
+
+    Returns
+    -------
+    plot_colors : `dict` of `str`
+        Mapping of the LSST bands to colors.
+    """
+    plot_filter_colors_white_background = {
+        "u": "#0c71ff",
+        "g": "#49be61",
+        "r": "#c61c00",
+        "i": "#ffc200",
+        "z": "#f341a2",
+        "y": "#5d0000",
+    }
+    plot_filter_colors_black_background = {
+        "u": "#3eb7ff",
+        "g": "#30c39f",
+        "r": "#ff7e00",
+        "i": "#2af5ff",
+        "z": "#a7f9c1",
+        "y": "#fdc900",
+    }
+    if dark_background:
+        return plot_filter_colors_black_background
+    else:
+        return plot_filter_colors_white_background
+
+
+def get_multiband_plot_symbols() -> Dict:
+    """Get symbol mappings for multiband plots using SDSS filter names.
+
+    Notes
+    -----
+    From https://rtn-045.lsst.io/#colorblind-friendly-plots
+
+    Returns
+    -------
+    plot_symbols : `dict` of `str`
+        Mapping of the LSST bands to symbols.
+    """
+    plot_symbols = {
+        "u": "o",
+        "g": "^",
+        "r": "v",
+        "i": "s",
+        "z": "*",
+        "y": "p",
+    }
+    return plot_symbols
+
+
+def get_multiband_plot_linestyles() -> Dict:
+    """Get line style mappings for multiband plots using SDSS filter names.
+
+    Notes
+    -----
+    From https://rtn-045.lsst.io/#colorblind-friendly-plots
+
+    Returns
+    -------
+    plot_linestyles : `dict` of `str`
+        Mapping of the LSST bands to line styles.
+    """
+    plot_line_styles = {
+        "u": "--",
+        "g": ":",
+        "r": "-",
+        "i": "-.",
+        "z": (0, (3, 5, 1, 5, 1, 5)),
+        "y": (0, (3, 1, 1, 1)),
+    }
+    return plot_line_styles

tests/test_matplotlib_figures.py

@@ -22,7 +22,12 @@
 import unittest
 
 import lsst.utils.tests
-from lsst.utils.plotting import make_figure
+from lsst.utils.plotting import (
+    get_multiband_plot_colors,
+    get_multiband_plot_linestyles,
+    get_multiband_plot_symbols,
+    make_figure,
+)
 
 try:
     from matplotlib.backends.backend_agg import FigureCanvasAgg
@@ -45,7 +50,22 @@ def testMakeFigure(self):
             self.assertEqual(fig.get_figheight(), 6)
             self.assertEqual(fig.get_dpi(), 300)
 
+            bands = ["u", "g", "r", "i", "z", "y"]
+
             ax = fig.add_subplot(111)
-            ax.plot([0, 1], [0, 1], "r-")
+            for dark_background in True, False:
+                colors = get_multiband_plot_colors(dark_background=dark_background)
+                symbols = get_multiband_plot_symbols()
+                linestyles = get_multiband_plot_linestyles()
+
+                ax = fig.add_subplot(111)
+                for band in bands:
+                    ax.plot(
+                        [0, 1],
+                        [0, 1],
+                        c=colors[band],
+                        marker=symbols[band],
+                        linestyle=linestyles[band],
+                    )
 
             fig.savefig(tmpFile)