# qe-sight-line

这个组件主要用于三维中添加通视分析,支持场景通视分析的添加、修改、清除。通视分析是三维 GIS 中常用的分析功能，用于判断三维场景中任意两点之间的通视情况。可根据在 3D 空间中相对于某表面或多面体要素类提供的障碍的位置，计算观察点与被观察点之间的通视性，沿着这些点之间的视线确定可见性。通视分析需要用户指定观察点和被观察点，观察点与被观察点是一对多的关系，一个观察点可对应多个被观察点进行分析，一个被观察点只能对应一个观察点进行通视分析。分析结果输出线将沿着输入视线的可见与不可见部分进行划分，绿色表示可见，红色表示不可见。

# 实例

隐藏代码

<template>
  <div class="container">
    <div class="bar" style="position: absolute;top: 419px;right: 434px;">
      <el-button type="primary" size="mini" @click="add()">
        通视分析
      </el-button>
      <el-button type="danger" size="mini" @click="clear()">
        清除
      </el-button>
    </div>
    <qe-viewer
      :imagery-type="'AMap'"
      :default-view="defaultView"
      :location-bar="false"
      :viewer-mode="'3D'"
    >
      <qe-primitive-layer :visible="true" :name="'倾斜摄影图层'">
        <qe-tileset
          v-for="(url, index) in testJson"
          :key="index"
          :url="url"
          :is-zoom-to="true"
          :tileset-options="tilesetOptions"
          @ready="handleTileset"
        />
      </qe-primitive-layer>
      <qe-sight-line v-if="sightlineVisible" :view-position="viewPosition" :target-position="targetPosition" @ready="handlerSightLine" />
    </qe-viewer>
  </div>
</template>


<script>
import { QeViewer,QeSightLine,QePrimitiveLayer,QeTileset } from  '@qycloud/vue-qearth';
import 'vue2qearth/vue2qearth.css'
import ElementUI from 'element-ui'
import Vue from 'vue'
import 'element-ui/lib/theme-chalk/index.css'
Vue.use(ElementUI)
export default {
  components: {
    QeViewer,
    QeTileset,
    QePrimitiveLayer,
    QeSightLine
  },
  data() {
    return {
      testJson: ['http://221.226.186.58:8025/qearth-tileset/tileset.json'],
      defaultView: [122.06502636, 40.7235578, 1672, 357.62, -10.82, 359.99],
      viewPosition: [122.06011364397729, 40.74406988394376, 3.20640872214913 + 0.5],
      targetPosition: [122.06065617519384, 40.74473426286042, 17.19646067982428 + 0.5],
      sightlineVisible: false,
      tilesetOptions: {
        maximumMemoryUsage: 32,
        maximumScreenSpaceError: 16,
        baseScreenSpaceError: 1024,
        skipLevelOfDetail: true,
        dynamicScreenSpaceError: true,
        cullWithChildrenBounds: true,
        cullRequestsWhileMoving: true,
        preloadWhenHidden: true,
        preloadFlightDestinations: true,
        preferLeaves: true,
        loadSiblings: false
      }
    }
  },
  created() {},
methods: {
    handlerSightLine(sightline) {
      this.sightline = sightline
    },
    handleTileset(tileset) {
      tileset.setHeight(0)
    },
    add() {
      this.sightlineVisible = false
      this.sightlineVisible = true
    },
    clear() {
      this.sightlineVisible = false
    }
  }
}
</script>

<style lang="scss" scoped>
.container {
  height: 450px;
 
}
.bar {
  padding: 20px 15px 20px 12px;
  border: 2px solid #008aff70;
  .el-form {
    ::v-deep .el-form-item__label {
      color: #fff;
      font-size: 14px;
    }
    ::v-deep .el-input__inner {
      height: 30px;
      line-height: 30px;
      width: 130px;
      color: #fff;
      border-radius: 2px;
      background-color: transparent;
    }
    ::v-deep .el-form-item {
    margin-bottom: 10px;
}

  }
  position: absolute;
  right: 20px;
  top: 20px;
  z-index: 2;
  background-color: rgba(23, 49, 71, 0.8);
}
</style>

# Attributes

参数	说明	类型	可选值	默认值
viewPosition	视角点坐标，格式参照示例代码 `[lng-经度,lat-纬度,alt-高度]`	array	—	—
targetPosition	目标点坐标，格式参照示例代码 `[lng-经度,lat-纬度,alt-高度]`	array	—	—

# Events

覆盖物事件的使用请参照上面SightLine 实例

// 覆盖物可选事件
"ready" // 组件装载后，返回当前实例对象

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