Showing posts with label angular-cesium. Show all posts
Showing posts with label angular-cesium. Show all posts
angular-cesium

angular-cesium

December 24, 2017
Create map based applications using cesium and angular2 components. Focusing on high performance with easy usage. Check out our Demo that contains small app built with angular-cesium.

Getting started

  • install angular-cesium:
     $ npm install --save angular-cesium
    
  • Angular cli

  • If you didn't installed Angular CLI yet:
     $ npm install -g @angular/cli
    
  • start new project:
     $ ng new PROJECT_NAME
    $ cd PROJECT_NAME
    
  • Import and add AngularCesiumModule to your app root module:
     import { AngularCesiumModule } from 'angular-cesium';
    // ....
    @NgModule({
     declarations: [],
     imports: [
      // ...
      AngularCesiumModule.forRoot()
     ],
     bootstrap: [AppComponent]
    })
    export class AppModule {
    }
    $ cd PROJECT_NAME
    
  • AngularCesiumModule configuration

  • The main module should be loaded with .forRoot() in order to make the module perform enhancements to Cesium, However, the module can be loaded with out calling forRoot().
  • .forRoot() excepts an optional option object of type ModuleConfiguration where every option can be toggled on or off. If no options object is passed, a default one will be used.
Cesium fixes / enhancements:
  • Fix entities shadowing bug - fixEntitiesShadows
Cesium configuration
In order to use cesium you must serve some assets from cesium package. The following configuration is for angular-cli projects, for webpack users try this.
  • install cesium via:
     $ npm install --save cesium
    
  • Add cesium assets, script and css in .angular-cli.json file:
     "assets": [ // ...
          { "glob": "**/*", "input": "../node_modules/cesium/Build/Cesium", "output": "./assets/cesium" }
         ],
        "styles": [ // ...
          "../node_modules/cesium/Build/Cesium/Widgets/widgets.css"
        ],
        "scripts": [ // ...
          "../node_modules/cesium/Build/Cesium/Cesium.js"
        ],
    
  • Add CESIUM_BASE_URL in main.ts file , before bootstraping:
      // ...
      window['CESIUM_BASE_URL'] = '/assets/cesium';
      platformBrowserDynamic().bootstrapModule(AppModule);
    
  • Add declare var Cesium; to typing.d.ts file.
  • You can configure cesium viewer style:
     // styles.css
    html, body, #cesiumContainer {
        width: 100%;
        height: 100%;
        margin: 0;
        padding: 0;
        overflow: hidden;
    }
    $ cd PROJECT_NAME
    
  • Live long and prosper

Demo

  • You can try and learn about angular-cesium from our demo: http://www.angular-cesium.com ( most optimized as desktop application ).
  • The demo contains 2 examples
    • Real data: showing real planes using GraphQL to warp an exiting REST service.
    • Simulated data: displaying planes data and sending using Socket.io.
        $ git clone https://github.com/TGFTech/angular-cesium.git
      $ cd angular-cesium
      $ yarn
      $ yarn server
      $ yarn start
      $ open http://localhost:8080
      

Basic example

  • In your HTML file :
      <ac-map>  
        <ac-layer acFor="let plane of planes$" [show]="showTracks" [context]="this">  
          <ac-billboard-desc props="{  
               image: plane.image,  
               position: plane.position  
              }">  
          </ac-billboard-desc>  
          <ac-label-desc props="{  
              position: plane.position,  
              text: plane.name  
          }">  
          </ac-label-desc>  
        </ac-layer>  
      </ac-map>  
    

  • ac-map creates the map
  • ac-layer component represent an array of entities that will be displayed on the map.
    • acFor attribute accepts an RxObserver planes$ , ac-layer will subscribe to the observer and will handle all updates for you.
  • Add descriptions components to determine which entity to render, in our example: ac-billboard and ac-label .
    • This example will render a billboard(icon) and label for each plane in the stream.
    • props accepts the same member options as cesium corresponding class. For example ac-billborad-desc accepts same members as cesium Billboard.

AC Layer

ac-layer is a directive which is meant to define a whole layer. In case you have previous knowledge about CesiumJs, you would notice that there are lots of map objects e.g. billboard, label, etc'. In the real world - we would like to merge all of this map objects into a single entity e.g. an airplane consists of a billboard(icon) and a label. Now, let's create a simple airplanes layer and go through it's definitions: First of all - the data source for a layer must be an RxJs stream. Second - every notification on the stream should be of type AcNotification:
 export class AcNotification {  
      id: number;  
      entity?: AcEntity;  
      actionType: ActionType;  
 }  
id - unique entity key, entity- the data itself for the entity, actionType- presents what happened to the entity. actionType can be one of those values:
 export enum ActionType {  
      ADD_UPDATE,  
      DELETE  
 }  
In case ADD_UPDATE is passed - the entity will be created or updated depending on if it exists or not. In case DELETE is passed - the entity will be removed from the map.
Now, assuming that each entity on this stream presents a plane, lets assume that each plane consists of this schema:
  • position - which presents the current plan position
  • name - which presents the plane name(to be presented on the map).
  • image - the PNG or whatever image you may like to use.
Now, Let's look at this piece of code:
 <ac-map>  
    <ac-layer acFor="let plane of planes$" [context]="this" [store]="true">  
      <ac-billboard-desc props="{  
           image: plane.image,  
           position: plane.position  
          }">  
      </ac-billboard-desc>  
      <ac-label-desc props="{  
          position: plane.position,  
          text: plane.name,  
          fillColor: getColor(plane)  
      }">  
      </ac-label-desc>  
    </ac-layer>  
  </ac-map>  
  • ac-map - Is a directive which presents the map and create a new Cesium instance.
  • ac-layer - Is our current directive which presents a plan layer. Remember that the data source must be a stream? In our case the stream is planes$.
  • acFor - Is a directive which lets you decide how would you call a single plane(or a single entity on the stream) in order to write the relevant expressions inside the directive(we'll see this in a moment). It should be noticed that the format for acFor is: let {x} of {our stream}.
  • context - The context of the observable (planes$) and the cesium descriptions props (same context as getColor). Usually it will be the context of the component itself - this.
  • store - Default: false. Tells Ac-Layer if it should store the entities it receives. The entities stored in the Ac-Layer store are extends by notifications from the stream (planes$).The store is an <entity id, entity> map. This in an optional basic data store. You can you use any kind of third party data store (e.g. ngrx/store).
Now, after we have defined our layer and decided that each entity on the stream will be called plane, let's drill down into the definitions of how an entity should look.
  • ac-billboard-desc - which presents billboard from CesiumJs. This directive allows you to pass props(expressions) to this billboard. You may see that although we do pass props - we actually pass expressions that are based on the plane that we defined earlier. Actually we say: 'Dear angular-cesium, please create and manage a billboard using those expressions for each plane'. Now, when an entity is passed through the stream - based on it's id, actionType and entity - angular-cesium will know what to do. When passing data with the same id and actionType=ADD_UPDATE - the entity will be updated on the map for every message.
  • ac-label-desc - the same as ac-billboard-desc but just for labels. It should be mentioned that ac-billboard-desc & ac-label-desc are all exposing the same API as Cesium expose for each map-entity.
It is important to mention that angular-cesium doesn't duplicate the description component over the DOM for each different plane in $plane (as ngFor does).

why? because there is no reason to, cesium entities are drawn on the canvas map using javascript API i.e. entities aren't represented as HTML, by doing so we gain a major boost in performance.
After explaining a little bit about ac-layer we hope that you may see it's benefits:
  • Easily defining a layer
  • Easily add/update/remove entities - all you have to do is pass a message through the stream and angular-cesium will keep track of all the rest.
  • Readable code - when reading your html which describes your layer - it is pretty easy to understand how your layer would look.
  • Maintainable code.

Supported Entity types

ac-entity-desc vs ac-entity

  • ac-entity-desc component is used to describe how each entity / array of entities in a stream of entities, managed inside ac-layer, should be drawn.
  • ac-entity-primitive-desc component is the same as ac-entity-desc with the difference of using Primitives to render the graphics. It is more efficient than ac-entity-desc when drawing an updating entity.
  • ac-entity component is used to draw an entity directly on the map, and so, can be used directly under ac-map.

Entities API

  • All of the entity components are using a flatten Cesium Entities API.
  • e.g: ac-billboard props input accepts a JSON which can have all properties found in Cesium Entity (like position) plus all properties found in Cesium BillboardGraphics (like).
  • In AngularCesium, entities have a default height of 0 (except of Billboards and Labels). This as in line with Cesium docs. For some reason in Cesium itself, the default height is undefined which leads Cesium to use GroundPrimitive which is less efficient. As a result, if you want your entity to be more efficient, set height: 0 or any other value in the props.

Map Events

MapEventsManagerService is a util service for managing all the map events (Click, Mouse_up...), it expose easy API for entity selection, event priority management and adds custom events (drag and drop, long press).
Usage:
 @Component(...)  
 export class SomeComponent{  
  constructor(private eventManager: MapEventsManagerService){  
   // Input about the wanted event   
   const eventRegistration: EventRegistrationInput = {  
    event: CesiumEvent.LEFT_CLICK, // event type enum. [required!]  
    modifier: CesiumEventModifier.CTRL, // event modifier enum. [optional]  
    entityType: AcEntity, // raise event only if AcEntity is clicked. [optional]   
    priority: 0, // event priority, default 0 . [optional]  
    pick: PickOptions.PICK_FIRST // entity pick option, default PickOptions.NO_PICK. [optional]  
   };  
   const clickEvent = this.eventManager.register(eventRegistration).subscribe((result) => {  
      // The EventResult will contain:   
      // movement(screen location of the event), entities(your entities) , primitives( cesium primitives, like label,billboard...)  
         console.log('map click', result.movement, 'primitives:', result.primitives, 'entities', result.entities);  
        });  
  }   
 }  
In the example above we start listing to Click events. according to eventRegisration object.
  • eventManager.register()
    • Returns RxJs observer of type DisposableObservable<EventResult> that we can subsribe to.
    • To remove the event registration just do: resultObserver.dispose()
  • event: according to CesiumEvent enum. All cesium events are supported, includes additional events like DragNDrop and LongPress
  • entityType: it is possible to register to events on a specific entities types, e.g raise event only when TrackEntity is Clicked.
    • AcEntity is the base class for all angular-cesium entities, it is a part of AcNotification and is required for MapEventManager to work properly.
    • All entities should inherit from AcEntity
      e.g class TrackEntity extends AcEntity {}
  • Priority: by setting the priority you can register same events and only the one with the higher priority will be raised. For example lets say when you left_click on the map a context menu should appear but if you in a drag and drop state you want that left_click will raise a drop event only, you can achive this by setting different priority to each event.
  • PickOptions: according to the PickOptions enum, set the different strategies for picking entities on the map:
    • NO_PICK - will not pick entities
    • PICK_FIRST - first entity will be picked . use Cesium.scene.pick()
    • PICK_ONE - in case a few entities are picked plonter is resolved . use Cesium.scene.drillPick()
    • PICK_ALL - all entities are picked. use Cesium.scene.drillPick()
MapEventsManagerService is porivided by <ac-map/>, therefor has 2 possibilitis to reach it:
  • In any components under <ac-map/> hierarchy as seen in the example above (recomannded).
  • Using@viewChild and ac-map reference: acMapComponent.getMapEventManagerService() .
Checkout demo/app/components/event-test-layer/event-test-layer.component.ts for more examples.
All cesium map events run out side angular zone
Meaning that the the callback that you pass to map event manager will be executed outside of angular zone. That is because Cesium run outside of Angular zone in case for performance reasons , kind of ON_PUSH strategy.
For example if you update your html template for every map event and you want it to render, you should use ChangeDetectorRef or warp your function with NgZone.run()
 class MyComponent {  
  constructor(eventManager: MapEventsManagerService, ngZone: NgZone){  
    eventManager.register(eventRegistration).subscribe((result) => {  
      ngZone.run(()=>{  
        this.textShownInTheTemplateHtml = result.movment;  
      });   
     });  
  }  
 }  

Plonter

In case a two or more entities are in the same location and both are clicked you have a plonter (which entity should be picked?).
This is resolved according to the PickOptions that we pass to the event registration:
  • NO_PICK - non of the entities will be picked, you only interested in the map location.
  • PICK_FIRST - the first(upper) entity will be picked.
  • PICK_ALL - all entities are picked and returned.
  • PICK_ONE - only one should be picked, a context will appear allowing the client to choose which entity he wants, selected entity will be passed to the eventcall back.
angular-cesium comes with ac-default-plonter a basic implementation for the plonter context menu. showing a list of entities names to select from.
It is possible to create your own plonter context menu just take a look at ac-default-plonter implementation, and disable the default plonter:
 <ac-map [disableDefaultPlonter]="true"></ac-map>  

Map layers

With angular cesium you can define your map provider in a declarative way using ac-map-layer-provider :
  <ac-map-layer-provider *ngIf="appSettingsService.showMapLayer" [provider]="MapLayerProviderOptions.ArcGisMapServer"  
               [options]="{  
                 url : 'https://server.arcgisonline.com/ArcGIS/rest/services/World_Street_Map/MapServer'  
               }">  
   </ac-map-layer-provider>  
  • All cesium imagery map layers are supported , defined with [provider] according to the MapLayerProviderOptions enum
  • Pass additional configuration to [options] . url is mandatory.
  • Support multi map layers, map ordering and map image layer configuration.
  • Check out usage example from our demo here

3d Tiles

 <ac-3d-tile-layer  
     *ngIf="appSettingsService.show3dtiles"  
     [options]="{  
      url: 'https://beta.cesium.com/api/assets/1461?access_token=eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJqdGkiOiJkYWJmM2MzNS02OWM5LTQ3OWItYjEyYS0xZmNlODM5ZDNkMTYiLCJpZCI6NDQsImFzc2V0cyI6WzE0NjFdLCJpYXQiOjE0OTkyNjQ3NDN9.vuR75SqPDKcggvUrG_vpx0Av02jdiAxnnB1fNf-9f7s'  
     }">  
   </ac-3d-tile-layer>  

Camera Keyboard Control Service

 this.keyboardControlService.setKeyboardControls({  
    W: { action: KeyboardAction.CAMERA_FORWARD },  
    S: { action: KeyboardAction.CAMERA_BACKWARD },  
    D: { action: KeyboardAction.CAMERA_RIGHT },  
    A: { action: KeyboardAction.CAMERA_LEFT },  
   },  

MapsManagerService

Angular Cesium extends cesium api and expose additional features, but if you want to use pure cesium api you can use MapsManagerService to receive cesium viewer or any other util service that was created by ac-map.
 class MyComp {  
 constructor(mapsManagerService: MapsManagerService)  
      const viewer = mapsManagerService.getMap().getCesiumViewer();  
      const mapEventManager = mapsManagerService.getMap().getMapEventsManager();  
      const cameraService = mapsManagerService.getMap().getCameraService();  
 }  

Geometry Editors

Part of AngularCesiumWidgetsModule are useful geometry editors tool:
Try running our demo for examples (uncomment the relevant components in demo-map.component.html).

Documents

Check out our api Docs
Note: Special thanks to TGFTech
Contact: tgftechinc@gmail.com
Disclaimer: The blog is created to share angular directives information to geek, curious Angular Developers.