Example of interactive rectangular selection#

Once all the cells below have been executed, you will be able to press the Select button, drag a rectangle enclosing the sources you wish to select and see their names in the table at the right of the ipyaladin view.

ipyaladin example

[1]:

from ipyaladin import Aladin
from ipywidgets import Layout, Box, widgets

from astroquery.simbad import Simbad
import astropy.units as u

aladin = Aladin(
    layout=Layout(width="50%"),
    target="M 1",
    fov=0.2,
    show_projection_control=False,
    show_fullscreen_control=False,
)
button = widgets.Button(description="Select")


def on_button_clicked(_: any) -> None:
    """Button click event callback.

    It will trigger the rectangular selection in the Aladin widget.

    Parameters
    ----------
    _: any
        The button widget that triggered the event.
    """
    aladin.rectangular_selection()


button.on_click(on_button_clicked)
table_info = widgets.HTML(layout=Layout(height="auto", overflow="auto"))

box_layout = Layout(
    display="flex",
    flex_flow="row",
    align_items="stretch",
    width="100%",
    position="relative",
)
box = Box(children=[aladin, button, table_info], layout=box_layout)
box

[1]:

[2]:

table = Simbad.query_region("M 1", radius=0.1 * u.deg)
aladin.add_table(table)


def process_result(sources: dict) -> None:
    """Process the sources selected in the Aladin widget and display them in the table.

    Parameters
    ----------
    sources: dict
        The sources selected in the Aladin widget.
    """
    s = '<table border="1">'
    s += "<tr><th>MAIN_ID</th><th>RA</th><th>DEC</th></tr>"
    for source in sources:
        s += "<tr><td>%s</td><td>%s</td><td>%s</td></tr>" % (
            source["data"]["MAIN_ID"],
            source["data"]["RA"],
            source["data"]["DEC"],
        )
    s += "</table>"
    table_info.value = s


aladin.set_listener("select", process_result)
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