..  _managing_receptors:

Managing Receptors
==================

To view and edit receptors, right click a scenario in the Project Browser, then 
select **Edit Receptors** from the **Scenario Context Menu**. This will open an
interactive dialog where Discrete, Ring or Uniform Grid receptors can be defined.

.. image:: ../_static/Receptors1.png
   :width: 624
   :align: center
   :alt: Receptor Dialog

SOFEA uses the concept of a **Receptor Group** to organize receptors. For grid
receptors, this corresponds to ``Netid`` for ``GRIDCART`` receptors in AERMOD.
For discrete receptors, including rings, this corresponds to ``Arcid`` for
``EVALCART`` receptors in AERMOD.

The plot on the right-hand side shows all sources and receptors already 
defined within a Scenario. As receptors are added through the interactive 
dialog box, they are automatically added to the plot so that you can visually 
confirm that added receptors are placed at the desired locations. You can 
modify the color of group of receptors by double-clicking the square symbol
in the first column of the table.

Receptor groups, discrete and grid receptors can be defined at any time.
As ring receptors are linked to source geometry, these receptors can only
be defined after sources have been added to a source group.

Discrete
--------

Add or remove discrete Cartesian receptors. To add a discrete receptor, 
type in X and Y receptor coordinates and terrain elevation in meters, 
then click **Add**. Added receptors will be shown on the plot to the right. 
Receptors can be removed by highlighting a receptor or a group of 
receptors within the list of receptors and clicking **Remove**. 

In AERMOD, ``DISCCART`` keyword is reserved for discrete receptors. After
you save the modifications made to the **Discrete** tab, the AERMOD input
file will be populated with a list of ``RE DISCCART Xcoord Ycoord 
(Zelev Zhill) (Zflag)`` entries. Here, ``Xcoord`` and ``Ycoord`` will 
correspond to inserted coordinates, ``Zelev`` and ``Zhill`` to 
entered elevation or to 0 if elevation was not entered and ``Zflag`` to 
receptor flag height entered in the General Source setting 
(default is 1.5 m). 

.. image:: ../_static/Receptors2.png
   :width: 624
   :align: center
   :alt: Scenario Discrete Receptors Data

Rings
-----

Add a special type of discrete Cartesian receptors defined with the 
``EVALCART`` keyword in AERMOD, once the sources are defined in **Scenario**. 
These receptors are similar to discrete receptors defined with the 
``DISCCART`` keyword, but ``EVALCART`` also allows for grouping of 
receptors, in this case along equidistant "rings" surrounding  a source 
or a group of sources.


This set of receptors is especially useful for fumigation applications
when concentrations at the specific distances from the area source are
needed. Module within SOFEA creates receptors at the equal distance 
from the edge of all area sources specified in the **Buffer distance** 
field. Receptors are placed around the entire group of adjacent sources
rather than within any source, as demonstrated in the plot below.

From the drop down menu select the **Source Group** for which Rings of 
receptors are desired. Type in **Buffer distance** and **Receptor
spacing** in meters, then click **Add**. Added receptors 
will automatically appear on the plot to the right. 

As you save the modifications made to the **Rings** tab, the AERMOD input
file will be automatically populated with a list of ``RE EVALCART 
Xcoord Ycoord Zelev Zhill Zflag Arcid`` using the information
associated with the rings that were created: ``Xcoord`` and ``Ycoord`` 
will correspond to the coordinates of created Ring receptors, ``Zelev`` 
and ``Zhill`` will be entered as 0, ``Zflag`` will correspond to the 
receptor flag height entered in the General Source setting (default is 
1.5 m), and ``Arcid`` will correspond to the names of the created rings.

.. warning::
   Receptor rings will not automatically update if source geometry changes,
   or sources are added or removed from the source group. To update rings,
   you must select the group and click **Update** in the Receptor Editor.


.. image:: ../_static/Receptors1.png
   :width: 624
   :align: center
   :alt: Scenario Ring Receptors Data


Uniform Grid
------------

Add or remove Cartesian grid receptor networks, defined with ``GRIDCART``
keyword in AERMOD. To add gridded receptors, enter coordinates of the 
starting grid location -- this is the southwest corner of the gird. Enter
the number of receptors along the x and y-axis and required distance 
in meters between the receptors in x and y directions. Then press 
**Add**. Added receptors will automatically appear on the plot 
to the right. 

As you save the modifications made to the **Uniform Grid** tab, the AERMOD
input file will be populated with ``RE GRIDCART Netid`` lines where
``Netid`` represent receptor network identification code automatically
generated in SOFEA. Start and the end of the grid network will
be indicated with ``STA`` and ``END`` parameters. Parameters entered in
the **Uniform Grid** tab will be saved in AERMOD file in this format:  
``RE GRIDCART Netid XYINC Xinit Xnum Xdelta Yinit Ynum Ydelta`` where
``Xinit`` and ``Yinit`` correspond to the coordinates entered in the
**Starting grid location** field, ``Xnum`` and ``Ynum`` correspond to 
the values entered in the **Receptor count** field, and ``Xdelta`` and 
``Ydelta`` correspond to the values entered in the **Receptor spacing** 
field. 

.. image:: ../_static/Receptors3.png
   :width: 624
   :align: center
   :alt: Scenario Gridded Receptors Data