坐标小数点处理(truncate)

> npm install @turf/truncate

Takes a GeoJSON Feature or FeatureCollection and truncates the precision of the geometry.

接收 GeoJSON，返回四舍五入后的 GeoJSON。

参数

参数	类型	描述
geojson	GeoJSON	任意 GeoJSON 对象
options	Object	可配置项

options 选项

属性	类型	默认值	描述
precision	number	6	坐标的小数点精确位数
coordinates	number	3	最大坐标数(主要用于删除 z 坐标)
mutate	boolean	false	是否返回入参的 GeoJSON，为 true 性能能显著提高

返回

GeoJSON - layer with truncated geometry

GeoJSON - 四舍五入后的 GeoJSON

示例

var point = turf.point([70.46923055566859, 58.11088890802906]);
var options = { precision: 3, coordinates: 2 };
var truncated = turf.truncate(point, options);
//=truncated.geometry.coordinates => [70.469, 58.111]

基础用法

打开 几何(geojson): 小数位数(precision): 最大坐标数(coordinates):

<template>
  <base-map>
    <a-button
      type="primary"
      @click="
        () => {
          visible = true;
        }
      "
      >打开</a-button
    >
    <drawer :visible.sync="visible" :code="code">
      <a-row
        >几何(geojson): <geojson-obj :value.sync="turfObj1"></geojson-obj
      ></a-row>
      <a-row
        >小数位数(precision):<a-input-number
          v-model="precision"
        ></a-input-number
      ></a-row>
      <a-row
        >最大坐标数(coordinates):<a-input-number
          v-model="coordinates"
        ></a-input-number
      ></a-row>
      <a-row> <input type="button" value="执行" @click="handleClick" /></a-row>
      <a-row>
        <a-space><json :data="result"></json></a-space>
      </a-row>
    </drawer>

    <vue2ol-layer-vector>
      <vue2ol-source-vector :features="features1"> </vue2ol-source-vector>
    </vue2ol-layer-vector>
    <vue2ol-layer-vector :style-obj="styleRed">
      <vue2ol-source-vector :features="features"> </vue2ol-source-vector>
    </vue2ol-layer-vector>
  </base-map>
</template>
<script>
import * as turf from "@turf/turf";
import { getFeaturesFromTurf, styleRed } from "../../utils/index.js";
export default {
  data() {
    return {
      turfObj1: turf.polygon([
        [
          [119.82697608925122, 28.20411200111616],
          [120.24552910100064, 28.193212183101853],
          [120.37414695356948, 27.927256623552736],
          [120.06895204916886, 27.71144022686944],
          [119.67655860065376, 27.864037679069753],
          [119.82697608925122, 28.20411200111616],
        ],
      ]),
      rewindCoordinates: null,
      type: "origin",
      features: [],
      result: null,
      visible: true,
      precision: 2,
      coordinates: 2,
      styleRed,
    };
  },
  computed: {
    features1() {
      if (this.turfObj1) {
        return getFeaturesFromTurf(this.turfObj1);
      } else {
        return [];
      }
    },
    code() {
      return `this.result = turf.truncate(${JSON.stringify(this.turfObj1)},
{
    precision:${this.precision},
    coordinates:${this.coordinates}
});`;
    },
  },
  mounted() {
  },
  methods: {
    handleClick() {
      if (!this.turfObj1) {
        return;
      }
      try {
        this.features = [];
        this.result = null;

        this.result = turf.truncate(this.turfObj1, {
          precision: this.precision,
          coordinates: this.coordinates,
        });
        this.features = getFeaturesFromTurf(this.result);
      } catch (e) {
        this.result = {
          error: e.toString(),
        };
      }
    },
  },
};
</script>

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