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坡向分析示例

这个示例演示如何使用 DMap3D SDK 进行地形坡向分析，以颜色渐变显示地形的朝向。

效果预览​

在地形上以不同颜色显示坡面的朝向（东、西、南、北等方向），帮助理解地形走势。

完整代码​

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

function AspectAnalysis() {
  const containerRef = useRef<HTMLDivElement>(null)
  const viewerRef = useRef<Cesium.Viewer | null>(null)
  const toolRef = useRef<any>(null)
  const [isVisible, setIsVisible] = 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

    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,
      },
    })

    // 创建坡向分析工具
    const tool = new DMap3D.analysis.aspectAnalyse(viewer, {
      color: '#ff7300',
    })
    toolRef.current = tool

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

  const handleToggle = () => {
    const tool = toolRef.current
    if (!tool) return
    if (isVisible) {
      tool.hide()
    } else {
      tool.show()
    }
    setIsVisible(!isVisible)
  }

  const handleClear = () => {
    toolRef.current?.hide()
    setIsVisible(false)
  }

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

      <div className="control-panel">
        <h3>坡向分析</h3>
        <p>以颜色显示地形坡面朝向</p>

        <div className="buttons">
          <button onClick={handleToggle}>
            {isVisible ? '隐藏坡向' : '显示坡向'}
          </button>
          <button onClick={handleClear}>清除</button>
        </div>

        <div className="legend">
          <h4>方向说明</h4>
          <p className="legend-desc">不同颜色代表坡面朝向不同方向，便于分析地形走势和水流方向。</p>
        </div>
      </div>
    </div>
  )
}

export default AspectAnalysis

样式文件​

src/components/AspectAnalysis.css
.aspect-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: 10px; margin-bottom: 15px; }
.buttons button {
  flex: 1; padding: 8px 16px; border: none; border-radius: 4px;
  background: #1890ff; color: white; cursor: pointer; font-size: 14px;
}
.buttons button:hover { background: #40a9ff; }
.legend { border-top: 1px solid #e8e8e8; padding-top: 15px; }
.legend h4 { margin: 0 0 8px 0; font-size: 14px; color: #666; }
.legend-desc { font-size: 13px; color: #666; margin: 0; }

关键代码说明​

1. 创建坡向分析工具​

const tool = new DMap3D.analysis.aspectAnalyse(viewer, {
  color: '#ff7300', // 基础颜色
})

2. 显示/隐藏​

tool.show()  // 显示坡向分析
tool.hide()  // 隐藏坡向分析

3. 与坡度分析的区别​

分析类型说明工具
坡向分析坡面朝向（方向）aspectAnalyse
坡度分析坡面倾斜程度slopAnalyse

相关 API​