.. _dkapp_section_label:

DischargeKeeperApp
===================

The DischargeKeeper App (DKApp) can measure the discharge in rivers and channels in seconds, no need of ground control points neither cross section. The only information needed is the **river width** and the **water depth**, with this values and the recorded video, the DKApp delivers an **approximate** value of the discharge. If accurate measurements are needed, the data recorded with the DKApp can be reprocessed on the DischargeProcessing.

The main steps are:

- Open the DKApp to record a 5 seconds video.
- Let the DKApp know where the river is with 4 clicks.
- Enter the river width.
- Enter the water depth.



New measurement
---------------

After opening the DKApp, there are 2 options:

- New measurement
- Go to gallery

 
.. image:: /images/dkapp_1_page_start.jpg
    :width: 50%

When clicking on "New measurement" the camera will be activated and a 5 second video will be recorded after clicking on the red button. Before starting the recording, there is a 2 seconds count down, it is very important to keep the phone stable, if the there is too much movement a message will be shown and the recording will be restarted.


.. image:: /images/dkapp_2_record.jpg
    :width: 50%


.. _dkapp_section_velocity:

Measure velocity
----------------

To measure the velocity: 

1) click a point on the far shore
2) click a point on the close shore
3) click on the left of the far water line
4) click on the right of the far water line


.. image:: /images/dkapp_3_where_river_is.jpg
    :width: 50%

After the initial clicks it is possible to zoom using 2 fingers and to correct the precise positioning.


.. image:: /images/dkapp_5_zoom_to_marker.jpg
    :width: 50%


Enter the river with, i.e. the distance between clicks 1) and 2).


.. image:: /images/dkapp_4_river_width.jpg
    :width: 50%


After clicking on "Next" the DKApp will measure the surface velocity of the flow, this might take a few seconds.

.. image:: /images/dkapp_6_processing.jpg
    :width: 50%

Once it is done, the surface velocity field will be shown.

.. image:: /images/dkapp_8_result_vectors.jpg
    :width: 50%




Measure discharge
-----------------

For an approximate discharge enter an effective water depth

.. image:: /images/dkapp_7_result_values.jpg
    :width: 50%

For a detailed analysis the videos can be sent to the cloud and re-processed with DischargeProcessing

If the video is sent to the cloud a code will be generated which is needed for the reprocessing in the DischargeWeb


.. image:: /images/dkapp_10_upload_code.jpg
    :width: 50%


Gallery
-------

All recordings are saved locally, and they can be accessed from the main page by clicking on "Got to gallery"". Once in the gallery the measurements can be seen, reprocessed or deleted.


.. image:: /images/dkapp_9_gallery.jpg
    :width: 50%


Special icons
-------------

There are two icons in the start page, the left sets the units:


.. image:: /images/dkapp_icon_units.jpg
    :width: 10%

while the right one sets the language

.. image:: /images/dkapp_icon_lenguage.jpg
    :width: 10%


In the velocity page there are also two icons, the upper one allows to stop processing and save the video to the gallery

.. image:: /images/dkapp_icon_save_to_gallery.jpg
    :width: 10%

the lower one allows to stop processing and upload the video to the cloud

.. image:: /images/dkapp_icon_upload.jpg
    :width: 10%



Troubleshooting
---------------

There are few situations where the DKApp can fail. If the velocity measurement could not be done, the following message error will be displayed:

.. image:: /images/dkapp_fail.jpg
    :width: 50%


The source of the error can be:

- There is no movement in the scene, i.e. water stagnant
- The calibration failed. For this check that your 4 clicks are done as explained in  :ref:`dkapp_section_velocity`