topic Re: Fade back map outside of polygon in ArcGIS JavaScript Maps SDK Questions

Fade back map outside of polygon

rsharma — Thu, 05 Mar 2020 07:50:43 GMT

I have a simple map with polygons on graphics layer, i need to fade map outside that polygon and show polygon as a hole in the map. I get some relative answer in older version, but it is not helpful.

I want to show like this image

My code is below

let validSymbol,
newDevelopmentGraphic;

        /************************************************************
         * Creates a new WebMap instance. A WebMap must reference
         * a PortalItem ID that represents a WebMap saved to
         * arcgis.com or an on-premise portal.
         *
         * To load a WebMap from an on-premise portal, set the portal
         * url with esriConfig.portalUrl.
         ************************************************************/
        var webmap = new WebMap({
          portalItem: {
            // autocasts as new PortalItem()
            id: ""
          }
        });

        /************************************************************
         * Set the WebMap instance to the map property in a MapView.
         ************************************************************/
        var view = new MapView({
          map: webmap,
          container: "viewDiv",
          center: ['<?=$map_xy_coordinate['x']?>', '<?=$map_xy_coordinate['y']?>'],
          zoom: 15
        });

Re: Fade back map outside of polygon

RobertScheitlin__GISP — Thu, 05 Mar 2020 13:55:44 GMT

Rajni,

I get some relative answer in older version, but it is not helpful.

What relative answer in older version. A link would help. And why is it not helpful?

Re: Fade back map outside of polygon

rsharma — Fri, 06 Mar 2020 03:46:25 GMT

I find this link and it uses shape files that i don't use, and couldn't understand how to do it

Fade back map outside of polygon

Re: Fade back map outside of polygon

RobertScheitlin__GISP — Sun, 12 Dec 2021 02:27:17 GMT

Rajni,

You can do something like this:

...
        graphicsLayer.add(newDevelopmentGraphic);
        var mapExtent = view.extent.expand(9);
        var overlayGeom = geometryEngine.difference(mapExtent, newDevelopmentGraphic.geometry);

        var symbol2 = {
          type: "simple-fill",
          style: "solid",
          color: [129, 129, 129, 0.8],
          outline: {
            color: [255, 255, 255, 0],
            width: 0
          }
        };

        overLayGra = new Graphic({
          geometry: overlayGeom,
          symbol: symbol2
        });
        graphicsLayer.add(overLayGra);
      }‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍

But you would have to figure out how to update the overlay when the newDevelopmentGraphic is being moved or reshaped. I don't have any input on this since I do not think this is a good workflow. Of course you will have to add geometryEngine to your apps require array.

Re: Fade back map outside of polygon

rsharma — Wed, 11 Mar 2020 03:58:41 GMT

Its not working, It only show overlay on whole map.

like this my polygon also covered with overlay

This is my code:

I don't want to move and reshape the graphics so their is no need to think of it

Re: Fade back map outside of polygon

RobertScheitlin__GISP — Sun, 12 Dec 2021 02:27:20 GMT

Rajni,

Works fine for me. Compare the code to find your mistake.

<!DOCTYPE html>
<html>

<head>
  <meta charset="utf-8" />
  <meta name="viewport" content="initial-scale=1,maximum-scale=1,user-scalable=no" />
  <title>Intro to MapView - Create a 2D map - 4.14</title>
  <style>
    html,
    body,
    #viewDiv {
      padding: 0;
      margin: 0;
      height: 100%;
      width: 100%;
    }
  </style>

  <link rel="stylesheet" href="https://js.arcgis.com/4.14/esri/themes/light/main.css" />
  <script src="https://js.arcgis.com/4.14/"></script>

  <script>
    require(["esri/views/MapView",
      "esri/WebMap",
      "esri/Graphic",
      "esri/layers/GraphicsLayer",
      "esri/widgets/Sketch/SketchViewModel",
      "esri/geometry/Polygon",
      "esri/geometry/SpatialReference",
      "esri/geometry/support/webMercatorUtils",
      "esri/geometry/geometryEngine"
    ], function (MapView, WebMap, Graphic, GraphicsLayer, SketchViewModel, Polygon, SpatialReference, webMercatorUtils, geometryEngine) {

      let sketchViewModel,
        validSymbol,
        newDevelopmentGraphic,
        overLayGra;
      /************************************************************
       * Creates a new WebMap instance. A WebMap must reference
       * a PortalItem ID that represents a WebMap saved to
       * arcgis.com or an on-premise portal.
       *
       * To load a WebMap from an on-premise portal, set the portal
       * url with esriConfig.portalUrl.
       ************************************************************/
      var webmap = new WebMap({
        portalItem: {
          // autocasts as new PortalItem()
          id: "a8e76ad6641b46978f148cba03ab3e2d"
        }
      });

      /************************************************************
       * Set the WebMap instance to the map property in a MapView.
       ************************************************************/
      var view = new MapView({
        map: webmap,
        container: "viewDiv",
        center: [175.9258624, -37.55590445],
        zoom: 20
      });

      var graphicsLayer = new GraphicsLayer();
      webmap.add(graphicsLayer);

      setUpGraphicClickHandler();

      view.when(function () {
        // Add the boundary polygon and new lot polygon graphics
        addGraphics();

        // Create a new instance of sketchViewModel
        sketchViewModel = new SketchViewModel({
          view: view,
          layer: graphicsLayer,
          updateOnGraphicClick: false,
          defaultUpdateOptions: {
            // set the default options for the update operations
            toggleToolOnClick: false // only reshape operation will be enabled
          }
        });

        // Listen to sketchViewModel's update event to do
        // graphic reshape or move validation
        sketchViewModel.on(["update", "undo", "redo"], onGraphicUpdate);
        sketchViewModel.update([newDevelopmentGraphic], {tool: "reshape"});
      });

      function onGraphicUpdate(event) {
        // get the graphic as it is being updated
        const graphic = event.graphics[0];

        // check if the update event's the toolEventInfo.type is move-stop or reshape-stop
        // then it means user finished moving or reshaping the graphic, call complete method.
        // this will change update event state to complete and we will check the validity of the graphic location.
        if (
          event.toolEventInfo &&
          (event.toolEventInfo.type === "move-stop" ||
            event.toolEventInfo.type === "reshape-stop")
        ) {
          sketchViewModel.complete();
        } else if (event.state === "cancel" || event.state === "complete") {
          // graphic moving or reshaping has been completed or cancelled
          // if the graphic is in an illegal spot, call sketchviewmodel's update method again
          // giving user a chance to correct the location of the graphic
          sketchViewModel.update([graphic], {
            tool: "reshape"
          });
        } else {
          graphic.symbol = validSymbol;
        }
      }

      // This function is called when a user clicks on the view.
      function setUpGraphicClickHandler() {
        view.on("click", function (event) {
          // check if the sketch's state active if it is then that means
          // the graphic is already being updated, no action required.
          if (sketchViewModel.state === "active") {
            return;
          }
          view.hitTest(event).then(function (response) {
            var results = response.results;
            // Check if the new development graphic was clicked and pass
            // the graphic to sketchViewModel.update() with reshape tool.
            //console.log(results);
            results.forEach(function (result) {
              console.log(result.mapPoint);
              if (
                result.graphic.layer === sketchViewModel.layer &&
                result.graphic.attributes &&
                result.graphic.attributes.newDevelopment
              ) {
                sketchViewModel.update([result.graphic], {
                  tool: "reshape"
                });
              }
            });
          });
        });
      }

      function addGraphics() {
        const vertices = [
          [175.9258624, -37.55590445],
          [175.9258630667, -37.55587745],
          [175.9258671333, -37.5557153],
          [175.92626316670004, -37.5557216],
          [175.92625955, -37.5558657],
          [175.9262584333, -37.5559107333],
          [175.9258624, -37.55590445]
        ];

        const polygon = createGeometry(vertices);
        validSymbol = createSymbol([255, 255, 255, 0.3], "solid", 2, [
          255,121,5]);
        newDevelopmentGraphic = new Graphic({
          geometry: webMercatorUtils.geographicToWebMercator(polygon),
          symbol: validSymbol,
          attributes: {
            newDevelopment: "new store"
          }
        });
        graphicsLayer.add(newDevelopmentGraphic);
        var mapExtent = view.extent.expand(9);
        var overlayGeom = geometryEngine.difference(mapExtent, newDevelopmentGraphic.geometry);

        var symbol2 = {
          type: "simple-fill",
          style: "solid",
          color: [129, 129, 129, 0.8],
          outline: {
            color: [255, 255, 255, 0],
            width: 0
          }
        };

        overLayGra = new Graphic({
          geometry: overlayGeom,
          symbol: symbol2
        });
        graphicsLayer.add(overLayGra);
      }

      function createGeometry(vertices) {
        return new Polygon({
          rings: vertices,
          spatialReference: new SpatialReference({
            wkid: 4326
          })
        });
      }

      function createSymbol(color, style, width, outlineColor) {
        return {
          type: "simple-fill",
          style: style,
          color: color,
          outline: {
            color: outlineColor,
            width: width,
            style: "dash"
          }
        };
      }
    });
  </script>
</head>

<body>
  <div id="viewDiv"></div>
</body>

</html>‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍