Bathymetry

Display a fully underwater elevation layer.

100% © EMODnet

index.js

import { MapControls } from "three/examples/jsm/controls/MapControls.js";
import { CSS2DObject } from "three/examples/jsm/renderers/CSS2DRenderer.js";

import Extent from "@giro3d/giro3d/core/geographic/Extent.js";
import GeoTIFFSource from "@giro3d/giro3d/sources/GeoTIFFSource.js";
import Instance from "@giro3d/giro3d/core/Instance.js";
import ElevationLayer from "@giro3d/giro3d/core/layer/ElevationLayer.js";
import Map from "@giro3d/giro3d/entities/Map.js";
import Inspector from "@giro3d/giro3d/gui/Inspector.js";
import ColorMap, { ColorMapMode } from "@giro3d/giro3d/core/layer/ColorMap.js";
import AxisGrid from "@giro3d/giro3d/entities/AxisGrid.js";

function makeColorRamp(
  preset,
  discrete = false,
  invert = false,
  mirror = false,
) {
  let nshades = discrete ? 10 : 256;

  const values = colormap({ colormap: preset, nshades });

  const colors = values.map((v) => new Color(v));

  if (invert) {
    colors.reverse();
  }

  if (mirror) {
    const mirrored = [...colors, ...colors.reverse()];
    return mirrored;
  }

  return colors;
}

const extent = new Extent("EPSG:3857", 2285900, 2444000, 4230900, 4386100);

const instance = new Instance({
  target: "view",
  crs: "EPSG:3857",
  backgroundColor: null, // Make the canvas transparent
});

const map = new Map({
  extent,
  hillshading: true,
});
instance.add(map);

const source = new GeoTIFFSource({
  url: "https://3d.oslandia.com/giro3d/rasters/bathymetry-emodnet.cog.tif",
  crs: "EPSG:3857",
});

const min = -5200;
const max = -900;

const axisGrid = new AxisGrid({
  volume: {
    extent,
    floor: min,
    ceiling: 0,
  },
  ticks: {
    x: 20_000,
    y: 20_000,
    z: 500,
  },
});

instance.add(axisGrid);

const colorMap = new ColorMap(
  makeColorRamp("bathymetry"),
  min,
  max,
  ColorMapMode.Elevation,
);

map.addLayer(
  new ElevationLayer({
    name: "bathymetry",
    extent,
    source,
    colorMap: colorMap,
    minmax: { min, max },
  }),
);

const controls = new MapControls(instance.view.camera, instance.domElement);

controls.enableDamping = true;
controls.dampingFactor = 0.2;

const center = extent.centerAsVector2();

instance.view.camera.position.set(2195551, 4146310, 90_000);
controls.target.set(center.x, center.y, min);

instance.view.setControls(controls);

// Attach the inspector
Inspector.attach("inspector", instance);

const labelElement = document.createElement("span");
labelElement.classList.value = "badge rounded-pill text-bg-light";
labelElement.style.marginTop = "2rem";
const label = new CSS2DObject(labelElement);

label.visible = false;
instance.add(label);

function pick(mouseEvent) {
  const picked = instance.pickObjectsAt(mouseEvent, { where: [map] });

  if (picked.length > 0) {
    label.visible = true;
    const point = picked[0].point;
    label.element.innerText = `depth: ${Math.round(point.z)}m`;
    label.position.copy(point);
    label.updateMatrixWorld(true);
  } else {
    label.visible = false;
  }
  instance.notifyChange();
}

instance.domElement.addEventListener("mousemove", pick);

index.html

<!doctype html>
<html lang="en">
  <head>
    <title>Bathymetry</title>
    <meta charset="UTF-8" />
    <meta name="name" content="cog_bathymetry" />
    <meta
      name="description"
      content="Display a fully underwater elevation layer."
    />
    <meta name="viewport" content="width=device-width, initial-scale=1.0" />

    <link rel="icon" href="https://giro3d.org/images/favicon.svg" />
    <link
      href="https://giro3d.org/assets/bootstrap-custom.css"
      rel="stylesheet"
    />
    <script src="https://giro3d.org/assets/bootstrap.bundle.min.js"></script>
    <link
      rel="stylesheet"
      type="text/css"
      href="https://giro3d.org/latest/examples/css/example.css"
    />

    <style>
      #view canvas {
        background: rgb(132, 170, 182);
        background: radial-gradient(
          circle,
          rgba(132, 170, 182, 1) 0%,
          rgba(37, 44, 48, 1) 100%
        );
      }
    </style>
  </head>

  <body>
    <div id="view" class="m-0 p-0 w-100 h-100"></div>
    <div
      id="inspector"
      class="position-absolute top-0 start-0 mh-100 overflow-auto"
    ></div>

    <script type="module" src="index.js"></script>
    <script>
      /* activate popovers */
      const popoverTriggerList = [].slice.call(
        document.querySelectorAll('[data-bs-toggle="popover"]'),
      );
      popoverTriggerList.map(
        // bootstrap is used as script in the template, disable warning about undef
        // eslint-disable-next-line no-undef
        (popoverTriggerEl) =>
          new bootstrap.Popover(popoverTriggerEl, {
            trigger: "hover",
            placement: "left",
            content: document.getElementById(
              popoverTriggerEl.getAttribute("data-bs-content"),
            ).innerHTML,
            html: true,
          }),
      );
    </script>
  </body>
</html>

package.json

{
    "name": "cog_bathymetry",
    "dependencies": {
        "colormap": "^2.3.2",
        "@giro3d/giro3d": "0.41.0"
    },
    "devDependencies": {
        "vite": "^3.2.3"
    },
    "scripts": {
        "start": "vite",
        "build": "vite build"
    }
}