Skip to main content

Profile Analysis Example

This example demonstrates how to perform terrain profile analysis using the DMap3D SDK, generating an elevation profile chart along a path.

Preview​

The user draws a path on the map, and the system automatically samples terrain elevation along the path and generates a profile chart.

Complete Code​

src/components/ProfileAnalysis.tsx
import { useEffect, useRef, useState } from 'react'
import * as Cesium from 'cesium'
import DMap3D from 'dmap3d'
import './ProfileAnalysis.css'

function ProfileAnalysis() {
  const containerRef = useRef<HTMLDivElement>(null)
  const viewerRef = useRef<Cesium.Viewer | null>(null)
  const toolRef = useRef<any>(null)
  const [isActive, setIsActive] = useState(false)

  useEffect(() => {
    if (!containerRef.current) return

    Cesium.Ion.defaultAccessToken = 'your-cesium-ion-token'

    const viewer = new Cesium.Viewer(containerRef.current, {
      animation: false,
      fullscreenButton: false,
      geocoder: false,
      homeButton: false,
      sceneModePicker: false,
      selectionIndicator: false,
      timeline: false,
      navigationHelpButton: false,
      infoBox: false,
      baseLayerPicker: false,
      terrain: Cesium.Terrain.fromWorldTerrain(),
    })
    viewerRef.current = viewer

    // Fly to an area with terrain relief
    viewer.camera.flyTo({
      destination: Cesium.Cartesian3.fromDegrees(86.925, 27.988, 30000),
      orientation: {
        heading: Cesium.Math.toRadians(0),
        pitch: Cesium.Math.toRadians(-60),
        roll: 0,
      },
    })

    // Create profile analysis tool
    const tool = new DMap3D.analysis.profile(viewer, {
      perStep: 50,
      perExpansion: 20,
      showChart: true,
      chartPosition: {
        bottom: '20px',
        width: '600px',
        height: '240px',
      },
    })
    toolRef.current = tool

    // Listen for analysis completion
    tool.onAnalysisEnd(() => {
      setIsActive(false)
    })

    return () => {
      tool.destroy()
      viewer.destroy()
    }
  }, [])

  const handleStart = () => {
    toolRef.current?.activate()
    setIsActive(true)
  }

  const handleStop = () => {
    toolRef.current?.deactivate()
    setIsActive(false)
  }

  const handleClear = () => {
    const tool = toolRef.current
    if (!tool) return
    tool.clear()
    tool.hideChart()
    setIsActive(false)
  }

  return (
    <div className="profile-analysis">
      <div ref={containerRef} className="cesium-container" />

      <div className="control-panel">
        <h3>Profile Analysis</h3>
        <p>Draw a path on terrain to generate an elevation profile</p>

        <div className="buttons">
          <button onClick={handleStart} disabled={isActive}>
            {isActive ? 'Drawing...' : 'Start Analysis'}
          </button>
          <button onClick={handleStop} disabled={!isActive}>Stop</button>
          <button onClick={handleClear}>Clear</button>
        </div>

        <div className="tip">
          <h4>Instructions</h4>
          <ol>
            <li>Left-click to add path points</li>
            <li>Right-click to finish path drawing</li>
            <li>Profile chart appears automatically at the bottom</li>
          </ol>
        </div>
      </div>
    </div>
  )
}

export default ProfileAnalysis

Stylesheet​

src/components/ProfileAnalysis.css
.profile-analysis { position: relative; width: 100%; height: 100vh; }
.cesium-container { width: 100%; height: 100%; }

.control-panel {
  position: absolute; top: 20px; right: 20px;
  background: rgba(255, 255, 255, 0.95); padding: 20px;
  border-radius: 8px; box-shadow: 0 2px 8px rgba(0, 0, 0, 0.15); min-width: 250px;
}
.control-panel h3 { margin: 0 0 10px 0; font-size: 18px; }
.control-panel p { margin: 0 0 15px 0; color: #666; font-size: 14px; }
.buttons { display: flex; gap: 8px; margin-bottom: 15px; }
.buttons button {
  flex: 1; padding: 8px 12px; border: none; border-radius: 4px;
  background: #1890ff; color: white; cursor: pointer; font-size: 14px;
}
.buttons button:hover { background: #40a9ff; }
.buttons button:disabled { background: #d9d9d9; cursor: not-allowed; }
.tip { border-top: 1px solid #e8e8e8; padding-top: 15px; }
.tip h4 { margin: 0 0 8px 0; font-size: 14px; color: #666; }
.tip ol { padding-left: 20px; margin: 0; }
.tip li { font-size: 13px; margin: 4px 0; color: #666; }

Key Code Explanation​

1. Create Profile Analysis Tool​

const tool = new DMap3D.analysis.profile(viewer, {
  perStep: 50,       // Sample points per segment
  perExpansion: 20,  // Expansion points per segment
  showChart: true,   // Show profile chart
  chartPosition: {   // Chart position
    bottom: '20px',
    width: '600px',
    height: '240px',
  },
})

2. Control Chart Visibility​

tool.showChart()   // Show chart
tool.hideChart()   // Hide chart

3. Get Analysis Results​

const result = tool.getAnalysisResult()
// result: Array<{ distance: number, lnglat: [lng, lat, height] }>

Extended Features​

  1. Export Chart - Export the profile chart as an image
  2. Slope Annotation - Annotate slope changes on the profile chart
  3. Comparative Analysis - Compare profiles of multiple paths
  4. Line-of-Sight Analysis - Perform line-of-sight analysis based on the profile