.. only:: html

    .. note::
        :class: sphx-glr-download-link-note

        Click :ref:`here <sphx_glr_download_modeling_gallery_spatial_plot_point.py>`     to download the full example code
    .. rst-class:: sphx-glr-example-title

    .. _sphx_glr_modeling_gallery_spatial_plot_point.py:


.. _point-spatial-model:

Point Spatial Model
===================

This model is a delta function centered in *lon_0* and *lat_0* parameters provided:

.. math:: \phi(lon, lat) = \delta{(lon - lon_0, lat - lat_0)}

The model is defined on the celestial sphere in the coordinate frame provided by the user.

If the point source is not centered on a pixel, the flux is re-distributed
across 4 neighbouring pixels. This ensured that the center of mass position
is conserved.

Example plot
------------
Here is an example plot of the model:


.. code-block:: default


    from astropy.coordinates import SkyCoord
    from gammapy.maps import WcsGeom
    from gammapy.modeling.models import (
        Models,
        PointSpatialModel,
        PowerLawSpectralModel,
        SkyModel,
    )

    model = PointSpatialModel(lon_0="0.01 deg", lat_0="0.01 deg", frame="galactic",)

    geom = WcsGeom.create(
        skydir=SkyCoord("0d 0d", frame="galactic"), width=(1, 1), binsz=0.1
    )
    model.plot(geom=geom, add_cbar=True)




.. image:: /modeling/gallery/spatial/images/sphx_glr_plot_point_001.png
    :class: sphx-glr-single-img





YAML representation
-------------------
Here is an example YAML file using the model:


.. code-block:: default


    pwl = PowerLawSpectralModel()
    point = PointSpatialModel()

    model = SkyModel(spectral_model=pwl, spatial_model=point, name="pwl-point-model")
    models = Models([model])

    print(models.to_yaml())




.. rst-class:: sphx-glr-script-out

 Out:

 .. code-block:: none

    components:
    -   name: pwl-point-model
        type: SkyModel
        spectral:
            type: PowerLawSpectralModel
            parameters:
            - {name: index, value: 2.0, unit: '', min: .nan, max: .nan, frozen: false,
                error: 0}
            - {name: amplitude, value: 1.0e-12, unit: cm-2 s-1 TeV-1, min: .nan, max: .nan,
                frozen: false, error: 0}
            - {name: reference, value: 1.0, unit: TeV, min: .nan, max: .nan, frozen: true,
                error: 0}
        spatial:
            type: PointSpatialModel
            frame: icrs
            parameters:
            - {name: lon_0, value: 0.0, unit: deg, min: .nan, max: .nan, frozen: false,
                error: 0}
            - {name: lat_0, value: 0.0, unit: deg, min: -90.0, max: 90.0, frozen: false,
                error: 0}






.. _sphx_glr_download_modeling_gallery_spatial_plot_point.py:


.. only :: html

 .. container:: sphx-glr-footer
    :class: sphx-glr-footer-example



  .. container:: sphx-glr-download sphx-glr-download-python

     :download:`Download Python source code: plot_point.py <plot_point.py>`



  .. container:: sphx-glr-download sphx-glr-download-jupyter

     :download:`Download Jupyter notebook: plot_point.ipynb <plot_point.ipynb>`


.. only:: html

 .. rst-class:: sphx-glr-signature

    `Gallery generated by Sphinx-Gallery <https://sphinx-gallery.github.io>`_