@sitn/gg-lidar-viewer

A GeoGirafe panel to browse LiDAR tile indexes (a GeoJSON file or a STAC catalog) on the 2D map and view the selected COPC point clouds in a 3D split view powered by Giro3D.

Installation steps

1. Create your project based on GeoGirafe. To create a new GeoGirafe project, follow the instruction on https://gitlab.com/geogirafe/gg-viewer

2. Install this plugin using npm i @sitn/gg-lidar-viewer

3. In index.html add <lidar-viewer slot="main"></lidar-viewer> in the tag <girafe-lr-panel class="panel-right" dock="right">

4. Add a button to open the panel, with the following code in the buttonbar-grid

<button
  tip="lidar-viewer-panel"
  slot="menu-content"
  class="gg-icon-button gg-big"
  onclick="
    document.geogirafe.state.interface.lidarViewerVisible =
      !document.geogirafe.state.interface.lidarViewerVisible
  ">
  <svg viewBox="0 0 24 24" width="22" height="22" fill="currentColor" aria-hidden="true">
    <circle cx="3"  cy="9"  r="1.8"/>
    <circle cx="8"  cy="4"  r="1.8"/>
    <circle cx="14" cy="2"  r="1.8"/>
    <circle cx="20" cy="5"  r="1.8"/>
    <circle cx="21" cy="12" r="1.8"/>
    <circle cx="5"  cy="15" r="1.8"/>
    <circle cx="12" cy="13" r="1.8"/>
    <circle cx="18" cy="18" r="1.8"/>
    <circle cx="9"  cy="20" r="1.8"/>
    <circle cx="2"  cy="21" r="1.8"/>
  </svg>
</button>

5. In main.ts, import and register the plugin :

• Add import LidarViewerComponent from '@sitn/gg-lidar-viewer' in the list of imports
• Add iface['lidarViewerVisible'] = false; to the block that seeds custom panel toggle paths in the state before defining the elements
• Add customElements.define('lidar-viewer', LidarViewerComponent); in the girafeApp.isReady() promise

STAC catalogs

With STAC API as source, Load tiles loads the tile footprints of the catalog when it has some: the GeoJSON assets with role index of its collections (/collections), one Feature per item with its file URL (file_url) and item URL (item_url), as published by stac-lidar-aggregator, one per source collection. All of them are loaded at once:

• footprints of collections whose item_assets declare a point cloud (or no item_assets) are the COPC tiles of the map;
• footprints of collections whose item_assets declare a GeoTIFF list raster models (COG), which Raster models adds to the 2D map, under the tiles (raw elevations, lidar:render = raw, stretched from 200 to 2500 m).

A catalog without footprints is searched instead (/search), in the visible area only: move the map and load again for other areas.

The Collections list holds the collections that directly contain the tiles, grouped by the collection holding their footprints (e.g. a provider): one per footprint file, or the last of the items' properties.collection hierarchy (else their collection) for searches. They are unchecked at first: check one, or all for a group, to show its tiles on the map. Year keeps the tiles of one acquisition year (datetime).

Panel

• Source (collapsed at first) chooses the tile index: a GeoJSON URL or a STAC catalog.
• Click a tile on the map to select it and show it in 3D, shift-click to add or remove one; check tiles in the list to show them in 3D. Each tile has links to its STAC page (in STAC Browser when browserUrl is set), its file and a copy of its URL. A warning appears above maxVisibleTiles tiles shown at once.
• Copy link copies a link opening the tiles shown in 3D from the same point of view; the page's URL follows them (?stac_items=<item URL>,<item URL>&lidar_camera=<x,y,z of the camera and of its target>). A link with stac_items alone opens these STAC items in 3D, e.g. from stac-lidar-aggregator's "Voir en 3D" links.
• Classes shown drops the points of the unchecked ASPRS classes (ground, vegetation, buildings…) when loading them.
• Measures: coordinates of a point, distance, height, and a cross-section profile of the loaded points within 1 m of a line.
• View: fit the camera, follow the 2D map, and an orthophoto (SWISSIMAGE) laid flat under the points. The 3D view has a north arrow and its width can be dragged.
• The panel is in French, German, Italian and English, following GeoGirafe's language.

Configuration

Optional, in the extendedConfig section of your project's config.json:

"extendedConfig": {
  "lidarViewer": {
    "stacUrl": "https://example.com/stac/",
    "browserUrl": "https://example.com/browser/",
    "lazPerfPath": "laz-perf",
    "maxVisibleTiles": 10,
    "orthophoto": { "capabilities": "https://wmts.geo.admin.ch/EPSG/2056/1.0.0/WMTSCapabilities.xml", "layer": "ch.swisstopo.swissimage" }
  }
}

• stacUrl: default STAC catalog: the panel opens on STAC API and loads it the first time it opens.
• browserUrl: the STAC Browser of that catalog, for the tiles' STAC pages (item URLs starting with stacUrl).
• lazPerfPath: directory serving laz-perf.wasm (copy node_modules/laz-perf/lib/laz-perf.wasm into your public/), relative to the page; by default it is loaded from a CDN.
• maxVisibleTiles (default 10) and orthophoto (WMTS capabilities and layer, default SWISSIMAGE).

The 3D view is in Swiss LV95 (EPSG:2056), the coordinate system of the COPC files it is made for.