odin_bushfire

The odin_bushfire crate is an application domain crate to download, display and update information about bushfires from Geoscience Australia servers.

The specific data set supported by odin_bushfire is the Near Real-Time National Bushfire Extents set, which is distributed in form of GeoJSON files.

odin_bushfire follows the common ODIN application domain crate structure, i.e. it consists of

• a lib.rs module defining the data model
• an actor.rs module providing a odin_actor::Actor implementation for data import and update
• a service.rs module providing a odin_server::spa::SpaService implementation for a bushfire micro service
• a odin_bushfire.js client (browser) Javascript module to interactively browse and display bushfire objects on top of a virtual globe

                                                    odin │ external      
     ODIN/                                               │               
       configs/            ┏━━━━━━━━━━━━━━━━━━━━┓        │               
         odin_bushfire/    ┃ BushfireActor      ┃        │  ┌───────────┐
           bushfire.ron ───►                    ┃           │  external │
                           ┃          ┌────────────────────►│   data    │
     ODIN/                 ┃          │         ┃           │  server   │
       cache/              ┃  ┌──────────────┐  ┃        │  └───────────┘
         odin_bushfire/    ┃  │ BushfireStore│  ┃        │               
           <data>          ┃  └──────────────┘  ┃        │               
                           ┃    update_action   ┃                        
                           ┗━━▲━━━━━━━━━━━━━━━━━┛                                                                   
                              │      │                                   
                exec_snapshot │      │                                   
            ┌─────────────────┼──────┼──┐                                
            │ SpaServerActor  │      │  │                                
            │      ┏━━━━━━━━━━━━━━━┓ │  │                                
            │      ┃BushfireService┃ │  │                                
            │      ┗━━━━━━━━━━▲━━━━┛ │  │                                
            └─────────────────┼──────┼──┘                                
                              │   wss│               server              
         ──────────────────── │ ──── │ ────────────────────              
                              │      │               client              
┌────────────────────────┐   ┌┴──────▼──────────┐                        
│ odin_bushfire_config.js┼──►│ odin_bushfire.js │                        
└────────────────────────┘   └──────────────────┘                        

While many other crates following this structure have more complex data retrieval protocols odin_bushfire just periodically retrieves a single file through http and hence does not have a dedicated connector object/task. Since file sizes are small enough (<1MB), the external server is fast enough and the BushfireActor only has one runtime message to react to (ExecSnapshotAction in response to a new connection) the retrieval is performed from within the actor upon receiving a Timer message from a local repeat timer that uses a configured interval (BushfireConfig.check_interval).

Similar to odin_fires the odin_bushfire crate does unpack the downloaded, continent-wide geojson file and breaks it up into Bushfire objects, storing respective polygons in (potentially large) separate geojson files.

The BushfireStore used by the BushfireActor is a tuple struct for a HashMap<String,VecDeque<Bushfire>>, i.e. it uses the unique bushfire id to store the most recently retrieved Bushfire records in a ring buffer, only sending updates for changed entries to clients. Clients in turn only download the geojson polygon files on demand when the user requests a specific bushfire perimeter.

As with the data from the US WFIGS Current Interagency Fire Perimeters the challenge is handle incomplete/missing feature properties.

Configuration

// sample config for odin_bushfire
BushFireConfig (
    url: "https://services-ap1.arcgis.com/ypkPEy1AmwPKGNNv/ArcGIS/rest/services/Near_Real_Time_Bushfire_Boundaries_view/FeatureServer/3/query?where=area_ha+%3E+0.001&outFields=*&f=pgeojson",
    dem: Some(File("$ODIN_ROOT/data/odin_dem/srtm-1sec-aus-i16.tif")), // or server url
    check_interval: Duration( secs: 1800, nanos: 0),  // check every 30min for updates
    max_history: 10, // number of records per fire we keep (in a ringbuffer)
    max_age: Duration( secs: 604800, nanos: 0), // ignore fires that were reported before (older than 1 week)
    max_file_age: Duration( secs: 86400, nanos: 0) // keep files for one day
)

Web Application User Interface

odin_bushfire has a single web application user interface window (titled “Bushfire”) to browse data sets.

The “fires” panel shows the Bushfire entries that match the criteria according to the checkboxes (state, type of bushfire, size of bushfire). Each fire is represented as a single line with basic information such as area, number of available updates and latest update.

Selecting a bushfire entry populates the list that shows each available update. Selecting the “show” checkbox of a line displays the perimeter on the virtual globe.

Since the stored fire id is not well suited for display we assign a shorter internal #<number> to correlate between the user interface and the virtual globe.

Double clicking on a bushfire item zooms/pans the globe to the most recent location.

Selecting a fire symbol (point or bitmap) on the virtual globe selects the corresponding list item in the “Bushfire” window.

The “fire info” panel shows additional alphanumeric information associated with the fire (e.g. global id and reporting agency)