Geometry operator - offset analysis | Sample | ArcGIS Maps SDK for JavaScript

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    <title>Geometry operator - offset analysis | Sample | ArcGIS Maps SDK for JavaScript</title>

    <!-- Load the ArcGIS Maps SDK for JavaScript from CDN -->
    <script type="module" src="https://js.arcgis.com/5.0/"></script>

    <style>
      html,
      body {
        height: 100%;
        margin: 0;
      }
    </style>
  </head>

  <body>
    <calcite-shell content-behind>
      <arcgis-map basemap="topo-vector" zoom="5" center="24, 28"></arcgis-map>

      <calcite-shell-panel slot="panel-end" display-mode="float">
        <calcite-panel>
          <calcite-block expanded id="parametersPanel" heading="Parameters">
            <calcite-label>
              <span>Offset distance:</span>
              <span id="offsetLabel"></span>
              <calcite-slider
                id="offsetSlider"
                value="75000"
                label-handles
                label-ticks
                max="100000"
                min="-100000">
              </calcite-slider>
            </calcite-label>

            <p>
              NOTE: for purposes of offset, <code>Polygons</code> are always "oriented"-
              counterclockwise rings are reversed to produce uniformly clockwise rings. This means a
              negative offset will <b>expand</b> <code>Polygons</code> whereas a positive offset
              will <b>contract</b> them.
            </p>

            <hr />

            <calcite-label>
              <span>Join type:</span>
              <calcite-radio-button-group id="offsetJoins" layout="vertical">
                <calcite-label layout="inline">
                  <calcite-radio-button value="miter" checked="true"></calcite-radio-button>
                  miter
                  <calcite-slider
                    disabled="true"
                    style="width: 100px"
                    id="miterLimitSlider"
                    value="10"
                    label-handles
                    label-ticks
                    max="20"
                    min="0">
                  </calcite-slider>
                  <calcite-tooltip
                    style="--calcite-tooltip-border-color: black"
                    reference-element="miterLimitSlider">
                    miter limit (in units of offset distance)
                  </calcite-tooltip>
                </calcite-label>
                <calcite-label layout="inline">
                  <calcite-radio-button value="bevel"></calcite-radio-button>
                  bevel
                </calcite-label>
                <calcite-label layout="inline">
                  <calcite-radio-button value="round"></calcite-radio-button>
                  round
                </calcite-label>
                <calcite-label layout="inline">
                  <calcite-radio-button value="square"></calcite-radio-button>
                  square
                </calcite-label>
              </calcite-radio-button-group>
            </calcite-label>

            <hr />

            <calcite-label>
              Join type demo angle:
              <calcite-slider
                id="joinTypeDemoAngleSlider"
                value="60"
                label-handles
                label-ticks
                max="180"
                min="-180">
              </calcite-slider>
            </calcite-label>
            <calcite-tooltip
              style="--calcite-tooltip-border-color: black"
              reference-element="joinTypeDemoAngleSlider">
              Measured as the angle between
              <br />
              the tangent vectors of the segments
              <br />
              before and after the vertex
            </calcite-tooltip>
            <span id="joinTypeExplanation"></span>
          </calcite-block>
        </calcite-panel>
      </calcite-shell-panel>
    </calcite-shell>

    <script type="module">
      const [
        FeatureLayer,
        Graphic,
        Polygon,
        Polyline,
        SpatialReference,
        GraphicsLayer,
        CIMSymbol,
        offsetOperator,
      ] = await $arcgis.import([
        "@arcgis/core/layers/FeatureLayer.js",
        "@arcgis/core/Graphic.js",
        "@arcgis/core/geometry/Polygon.js",
        "@arcgis/core/geometry/Polyline.js",
        "@arcgis/core/geometry/SpatialReference.js",
        "@arcgis/core/layers/GraphicsLayer.js",
        "@arcgis/core/symbols/CIMSymbol.js",
        "@arcgis/core/geometry/operators/offsetOperator.js",
      ]);

      // Get a reference to the map component
      const viewElement = document.querySelector("arcgis-map");

      const tunisia = new Polygon({
        rings: [
          false
            ? [
                [900000, 400000],
                [125000, 400000],
                [1250000, 4500000],
                [900000, 4500000],
                [900000, 4000000],
              ]
            : [
                [900000, 4000000],
                [900000, 4500000],
                [1250000, 4500000],
                [1250000, 4000000],
                [900000, 4000000],
              ],
        ],
        spatialReference: SpatialReference.WebMercator,
      });

      const aeniad = new Polyline({
        paths: [
          [
            [2920000, 4850000],
            [2750000, 5000000],
            [2750000, 4200000],
            [2150000, 5000000],
            [1700000, 4500000],
            [1700000, 4250000],
            [1400000, 4250000],
            [1400000, 4550000],
            [1600000, 5000000],
            [1400000, 5100000],
          ],
        ],
        spatialReference: SpatialReference.WebMercator,
      });

      const symbols = {
        showOrientationWithArrows: new CIMSymbol({
          data: {
            type: "CIMSymbolReference",
            symbol: {
              type: "CIMLineSymbol",
              symbolLayers: [
                {
                  // arrow symbol
                  type: "CIMVectorMarker",
                  enable: true,
                  size: 5,
                  markerPlacement: {
                    type: "CIMMarkerPlacementAlongLineSameSize", // places same size markers along the line
                    endings: "WithMarkers",
                    placementTemplate: [19.5], // determines space between each arrow
                    angleToLine: true, // symbol will maintain its angle to the line when map is rotated
                  },
                  frame: {
                    xmin: -5,
                    ymin: -5,
                    xmax: 5,
                    ymax: 5,
                  },
                  markerGraphics: [
                    {
                      type: "CIMMarkerGraphic",
                      geometry: {
                        rings: [
                          [
                            [-8, -5.47],
                            [-8, 5.6],
                            [1.96, -0.03],
                            [-8, -5.47],
                          ],
                        ],
                      },
                      symbol: {
                        // black fill for the arrow symbol
                        type: "CIMPolygonSymbol",
                        symbolLayers: [
                          {
                            type: "CIMSolidFill",
                            enable: true,
                            color: [0, 0, 0, 255],
                          },
                        ],
                      },
                    },
                  ],
                },
                {
                  // white dashed layer at center of the line
                  type: "CIMSolidStroke",
                  enable: true, // must be set to true in order for the symbol layer to be visible
                  capStyle: "Butt",
                  joinStyle: "Round",
                  width: 1,
                  color: [0, 0, 0, 255],
                },
              ],
            },
          },
        }),
        dottedLinesForConstruction: new CIMSymbol({
          data: {
            type: "CIMSymbolReference",
            symbol: {
              type: "CIMLineSymbol",
              symbolLayers: [
                {
                  type: "CIMSolidStroke",
                  effects: [
                    {
                      type: "CIMGeometricEffectDashes",
                      dashTemplate: [1, 2],
                      lineDashEnding: "NoConstraint",
                    },
                  ],
                  enable: true,
                  capStyle: "Round",
                  joinStyle: "Round",
                  miterLimit: 10,
                  width: 1,
                  color: [200, 115, 0, 255],
                },
              ],
            },
          },
        }),
      };

      const makeFeatureLayer = (geometry, symbol) => {
        return new FeatureLayer({
          source: [
            new Graphic({
              geometry,
              attributes: {
                ObjectID: 1,
                DepArpt: "KATL",
                MsgTime: Date.now(),
                FltId: "UAL1",
              },
            }),
          ],
          objectIdField: "ObjectID",
          renderer: {
            type: "simple",
            symbol,
          },
        });
      };

      const [tunisiaOffsetGraphic, aeniadOffsetGraphic, joinTypeDemoOffsetGraphic] = [
        Polygon,
        Polyline,
        Polyline,
        Polyline,
      ].map(
        (G) =>
          new Graphic({
            geometry: new G(),
            symbol: {
              type: "simple-line",
              color: [0, 0, 0, 0],
              width: 1.5,
            },
          }),
      );

      const tunisaFeatureLayer = makeFeatureLayer(tunisia, symbols.showOrientationWithArrows);
      const aeniadFeatureLayer = makeFeatureLayer(aeniad, symbols.showOrientationWithArrows);
      const joinTypeDemoLayer = makeFeatureLayer(new Polyline(), symbols.showOrientationWithArrows);
      const joinTypeConstructionLayer = makeFeatureLayer(
        new Polyline(),
        symbols.dottedLinesForConstruction,
      );
      const graphicsLayer = new GraphicsLayer({
        graphics: [tunisiaOffsetGraphic, aeniadOffsetGraphic, joinTypeDemoOffsetGraphic],
      });

      const setup = async () => {
        const offsetSlider = document.getElementById("offsetSlider");
        const offsetLabel = document.getElementById("offsetLabel");
        const offsetJoins = document.getElementById("offsetJoins");
        const miterLimitSlider = document.getElementById("miterLimitSlider");
        const joinTypeDemoAngleSlider = document.getElementById("joinTypeDemoAngleSlider");
        const joinTypeExplanationLabel = document.getElementById("joinTypeExplanation");

        offsetSlider.addEventListener("calciteSliderInput", onChange);
        miterLimitSlider.addEventListener("calciteSliderInput", onChange);
        offsetJoins.addEventListener("calciteRadioButtonGroupChange", onChange);
        joinTypeDemoAngleSlider.addEventListener("calciteSliderInput", onChange);

        await updateJoinTypeDemo(90, 0);
        await onChange();

        async function onChange() {
          const offset = offsetSlider.value;
          const joins = offsetJoins.selectedItem.value;
          miterLimitSlider.disabled = joins !== "miter";
          const miterLimit = miterLimitSlider.value;

          const joinTypeDemoAngle = joinTypeDemoAngleSlider.value;
          const joinIsInner = joinTypeDemoAngle > 0 !== offset >= 0;
          await updateJoinTypeDemo(joinTypeDemoAngle, offset, joins === "square", joinIsInner);

          for (const [offsetGraphic, geometry] of [
            [tunisiaOffsetGraphic, tunisia],
            [aeniadOffsetGraphic, aeniad],
            [joinTypeDemoOffsetGraphic, joinTypeDemoLayer.source.at(0).geometry],
          ]) {
            offsetGraphic.symbol.color = offset > 0 ? [0, 0, 200, 255] : [0, 180, 0, 255];
            offsetGraphic.geometry = offsetOperator.execute(geometry, offset, {
              joins,
              miterLimit,
            });
          }

          const sign = offset > 0 ? "positive" : "negative";
          const dir = offset > 0 ? "RIGHT" : "LEFT";
          const op = offset > 0 ? "CONTRACT" : "EXPAND";
          offsetLabel.textContent = `(${sign}; ${dir} side of directed path; ${op}S polygons)`;

          joinTypeExplanationLabel.innerHTML = joinIsInner
            ? "Inner corners are always mitered."
            : joinTypeExplanations[joins];
        }
      };

      const parallelLinesExplanation = `
  A line is constructed parallel to each segment, separated from the
  segment by the specified <code>offset</code>.
`;

      const joinTypeExplanations = {
        miter: `
    ${parallelLinesExplanation}
    The intersection of these lines is the mitered vertex.
    <br />
    If the distance between the mitered vertex and the original vertex
    is greater than <code>offset * miterLimit</code>, the mitered vertex
    is replaced with a bevel.
  `,
        bevel: `
    ${parallelLinesExplanation}
    The original vertex is projected onto each of these lines and the
    resulting points are used as the beginning and end of a line segment
    (the bevel).
  `,
        round: `
    ${parallelLinesExplanation}
    The original vertex is projected onto each of these lines and the
    resulting points are used as the beginning and end of a circular arc
    centered on the original vertex.
  `,
        square: `
    ${parallelLinesExplanation}
    The original vertex is projected onto each of these lines at a
    45degree angle instead of at 90degrees as in <code>bevel</code>. The
    resulting points are used as the beginning and end of a line segment.
    <br />
    If the resulting corner is not acute, a miter will be used instead.
  `,
      };

      async function updateJoinTypeDemo(angle, offset, isSquare, joinIsInner = false) {
        angle = (angle / 180) * Math.PI;

        const vertex = [2e6, 3e6];

        function rotate([x, y]) {
          const relx = x - vertex[0];
          const rely = y - vertex[1];
          return [
            vertex[0] + relx * Math.cos(angle) + rely * Math.sin(angle),
            vertex[1] + relx * Math.sin(angle) - rely * Math.cos(angle),
          ];
        }

        function translate([x, y], [dx, dy]) {
          return [x + dx, y + dy];
        }

        const pre = translate(vertex, [0, -1e6]);
        const post = rotate(pre);

        const offsetPre = translate(pre, [offset, 0]);
        const offsetPost = rotate(offsetPre);

        const bevelStart = translate(vertex, [offset, 0]);
        const bevelEnd = rotate(bevelStart);

        const squareStart = translate(vertex, [
          Math.abs(offset) * Math.sign(angle),
          offset * Math.sign(angle),
        ]);
        const squareEnd = rotate(squareStart);

        const extendedPre = translate(bevelStart, [0, 1e6]);
        const extendedPost = rotate(extendedPre);

        const d = -2e4;
        const rightAnglePre = [
          translate(vertex, [-d * Math.sign(offset), 0]),
          translate(vertex, [-d * Math.sign(offset), d]),
          translate(vertex, [0, d]),
        ];

        let graphic;

        graphic = joinTypeDemoLayer.source.at(0);
        graphic.geometry = new Polyline({
          paths: [[pre, vertex, post]],
          spatialReference: SpatialReference.WebMercator,
        });
        joinTypeDemoLayer.applyEdits({ updateFeatures: [graphic] });

        const extraConstructionPaths = [
          [bevelStart, vertex, bevelEnd],
          rightAnglePre,
          rightAnglePre.map(rotate),
          isSquare && Math.abs(angle) > Math.PI / 2 ? [squareStart, vertex, squareEnd] : [],
        ];

        graphic = joinTypeConstructionLayer.source.at(0);
        graphic.geometry = new Polyline({
          paths: [
            [offsetPre, extendedPre],
            [extendedPost, offsetPost],
            ...(joinIsInner ? [] : extraConstructionPaths),
          ],
          spatialReference: SpatialReference.WebMercator,
        });
        joinTypeConstructionLayer.applyEdits({ updateFeatures: [graphic] });
      }

      // Listen for when the view is ready
      // then start adding layers and setting up the app
      await viewElement.viewOnReady();
      viewElement.map.addMany([
        tunisaFeatureLayer,
        aeniadFeatureLayer,
        joinTypeDemoLayer,
        graphicsLayer,
        joinTypeConstructionLayer,
      ]);
      setup();
    </script>
  </body>
</html>