#Technical Specifications

##Software Details

This application was built for the purpose of computing reservoir volumes from a specified location within the Dominican Republic (Click here to go to the app). The application was designed using a python script, which was added to an ArcGIS Server as a geoprocessing service, and Tethys platform in combination with the ArcGIS API for JavaScript for the front end of the app. This application was created by Michael Souffront and Kyugene Lee.

####Installation:

######Prerequisites:

• Tethys Platform

Clone the repository:

$ git clone https://github.com/msouff/storageCapacityDR.git

Then install the app in Tethys Platform.

######Installation for App Development:

$ . /usr/lib/tethys/bin/activate
$ cd tethysapp-storage_capacity
$ python setup.py develop
$ tethys docker start
$ tethys manage start

######Installation for Production:

• For production installation follow the instructions in the following link: http://docs.tethysplatform.org/en/latest/production/app_installation.html

####Compatibility and Limitations

This application only works within the Dominican Republic. However, this same setup can be used with raster data from other places in order to get the app working at a different location. The features contained in this application are cross browser and will work with most current browsers. However, only Google Chrome and Mozilla Firefox were tested. Full functionality for other current browsers is expected but not guaranteed. An ArcGIS Server and general GIS knowledge is needed in order to implement the backend portion of this app; that is, preparing and loading raster and vector data and publising a geoprocessing service to an ArcGIS Server in order to calculate and store reservoir volume.

####License

This application is licensed under an open source MIT license.

####Application Design

A simple approach was taken when designing the front end part of the app. We tried to make as intuitive as possible. A help guide is provided in the app in case any of the steps necessary to run the app is not clear enough. The application was designed as a one-page website. It can be accessed from BYU Tethys portal (http://tethys.byu.edu/) as shown in Figure 1 below. A zoomed in image of the buttons used to calculate a potential dam and reservoir volume is shown in Figure 2. After running the application successfully, the calculated reservoir will appear on the main map window with the calculated reservoir volume in cubic meters, shown in Figure 3.

An alternative to using Tethys is possible, since this app mainly used the ArcGIS API for JavaScript for most of its functionality (see main.js file in the repository), however, an HTML page together with styling would need to be developed from zero to pursue this alternative.

Figure 1. Home page of Tethys Portal to access Storage Capacity application.

Figure 2. Functions used to properly run the application.

Figure 3. Final result after successfully running the Storage Capacity application.

####Main Files

The main files associated with this application include raster data (surface elevation, flow direction, and flow accumulation), a map service with the main streams in the Dominican Republic, and the geoprocessing service task to calculate storage capacity.

####Code Structure

The basic structure of the Python script that calculates storage capacity is shown in the flowchart below, Figure 4. The blue filled circles represent input features necessary for the geoprocessing task to run. The red filled shapes represent processing steps. The orange squares represent intermediate features, some of which are also saved as outputs (e.g. the watershed and reservoir features).

Figure 4. Python script structure diagram. This is a simplified diagram. The actual script uses more steps that the ones shown here.

####Key Functions

The following were some of the most important functions used with the ArcGIS API for JavaScript.

Function Name	Comments
drawPoint	End user places point on map
submitJob	Application runs the geoprocessing task
completeCallback	Calls functions to draw results on successfull job requeset
drawWatershed	Outlines resulting watershed polygon on map
drawReservoir	Outlines resulting reservoir polygon on map
getVolume	Makes request to retrieve volume data and calls function to display resulting reservoir volume