javascript - How to import geolib in React Native to calculate the distance between two points? - Stack Overflow

admin管理员组

文章数量:1323029

I need to calculate the distance between Longitude and Latitude in react native. I have the Longitude and Latitude of my current location and I have the Longitude and Latitude of my destination. Is their any easy way to calculate the distance?

I tried using geolib, but keep getting an error. Below is what I did:

npm i geolib

I put the geolib in my import statement too.

  import {
    AppRegistry,
    StyleSheet,
    FlatList,
    Text,
    View,
    Alert,
    TouchableOpacity,
    Linking,
    Image,
    ScrollView,
    RefreshControl,
    Location,
    geolib
  } from 'react-native';

 _renderItem = ({item, index}) => {

    var dist  = geolib.getDistance(
      this.state.latitude,
      this.state.longitude,
      item.LatL,
      item.Long2
    );

    return (
      <View>
        <Text>Latitude: {this.state.latitude}</Text>
        <Text>Longitude: {this.state.longitude}</Text>
        <Text>Latitude from file:{item.LatL}</Text>
        <Text>Longitude from file :{item.Long2} </Text>
        <Text style={styles.AddressSpace} >Miles:{dist }</Text>
      </View>
    );

Below is the error that I am getting:

TypeError: undefined is not an object
(evaluating '_reactNative.geolib.getDistance')

[![enter image description here][1]][1]

I am getting this error as soon as I put this code:

   const dist = geolib.getDistance(
      { latitude, longitude },{ latitude: item.LatL, longitude: item.Long2 }
    );

Not sure, but I am still getting the above error: Below is my entire code:

 import React, { Component } from 'react';
import { View, Text, item } from 'react-native';
import geolib from 'geolib';
class ServiceListDetails extends Component {
  constructor(props) {
    super(props);

    this.state = {
      latitude: null,
      longitude: null,
      error: null,
    };
  }

  ponentDidMount() {
    navigator.geolocation.getCurrentPosition(
      (position) => {
        this.setState({
          latitude: position.coords.latitude,
          longitude: position.coords.longitude,
          error: null,
        });
      },
      (error) => this.setState({ error: error.message }),
      { enableHighAccuracy: true, timeout: 20000, maximumAge: 1000 },
    );
  }

  render() {
    const { latitude, longitude } = this.state;

    const dist = geolib.getDistance(
  { latitude, longitude },
  { latitude: 33.935558, longitude: -117.284912 }
);
    return (
      <View style={{ flexGrow: 1, alignItems: 'center', justifyContent: 'center' }}>
        <Text>Latitude: {this.state.latitude}</Text>
        <Text>Longitude: {this.state.longitude}</Text>
        <Text>Miles:{dist} </Text>
        {this.state.error ? <Text>Error: {this.state.error}</Text> : null}
      </View>
    );
  }
}

export default ServiceListDetails;

_  [1]: .png

I need to calculate the distance between Longitude and Latitude in react native. I have the Longitude and Latitude of my current location and I have the Longitude and Latitude of my destination. Is their any easy way to calculate the distance?

I tried using geolib, but keep getting an error. Below is what I did:

npm i geolib

I put the geolib in my import statement too.

  import {
    AppRegistry,
    StyleSheet,
    FlatList,
    Text,
    View,
    Alert,
    TouchableOpacity,
    Linking,
    Image,
    ScrollView,
    RefreshControl,
    Location,
    geolib
  } from 'react-native';

 _renderItem = ({item, index}) => {

    var dist  = geolib.getDistance(
      this.state.latitude,
      this.state.longitude,
      item.LatL,
      item.Long2
    );

    return (
      <View>
        <Text>Latitude: {this.state.latitude}</Text>
        <Text>Longitude: {this.state.longitude}</Text>
        <Text>Latitude from file:{item.LatL}</Text>
        <Text>Longitude from file :{item.Long2} </Text>
        <Text style={styles.AddressSpace} >Miles:{dist }</Text>
      </View>
    );

Below is the error that I am getting:

TypeError: undefined is not an object
(evaluating '_reactNative.geolib.getDistance')

[![enter image description here][1]][1]

I am getting this error as soon as I put this code:

   const dist = geolib.getDistance(
      { latitude, longitude },{ latitude: item.LatL, longitude: item.Long2 }
    );

Not sure, but I am still getting the above error: Below is my entire code:

 import React, { Component } from 'react';
import { View, Text, item } from 'react-native';
import geolib from 'geolib';
class ServiceListDetails extends Component {
  constructor(props) {
    super(props);

    this.state = {
      latitude: null,
      longitude: null,
      error: null,
    };
  }

  ponentDidMount() {
    navigator.geolocation.getCurrentPosition(
      (position) => {
        this.setState({
          latitude: position.coords.latitude,
          longitude: position.coords.longitude,
          error: null,
        });
      },
      (error) => this.setState({ error: error.message }),
      { enableHighAccuracy: true, timeout: 20000, maximumAge: 1000 },
    );
  }

  render() {
    const { latitude, longitude } = this.state;

    const dist = geolib.getDistance(
  { latitude, longitude },
  { latitude: 33.935558, longitude: -117.284912 }
);
    return (
      <View style={{ flexGrow: 1, alignItems: 'center', justifyContent: 'center' }}>
        <Text>Latitude: {this.state.latitude}</Text>
        <Text>Longitude: {this.state.longitude}</Text>
        <Text>Miles:{dist} </Text>
        {this.state.error ? <Text>Error: {this.state.error}</Text> : null}
      </View>
    );
  }
}

export default ServiceListDetails;

_  [1]: https://i.sstatic/8VadZ.png

• javascript
• reactjs
• react-native

Share Improve this question Follow edited May 1, 2019 at 22:07 Anjali asked May 1, 2019 at 17:34 AnjaliAnjali 2,7081111 gold badges4747 silver badges9090 bronze badges 3

• Possible duplicate of Calculate distance between 2 GPS coordinates – jorbuedo Commented May 1, 2019 at 17:49
• Above answer is not in React Native. – Anjali Commented May 1, 2019 at 18:08
• none of the above answers are in react native. I checked before posting my question. – Anjali Commented May 1, 2019 at 20:39

Add a ment  | 

2 Answers 2

Sorted by: Reset to default 3

geolib doesn't exist as a named export in react-native.

import {
  AppRegistry,
  StyleSheet,
  FlatList,
  Text,
  View,
  Alert,
  TouchableOpacity,
  Linking,
  Image,
  ScrollView,
  RefreshControl,
  Location
  // Remove `geolib` from here.
} from 'react-native';

// Import the lib from the one you've just installed.
import geolib from 'geolib';

It helps to know how the import and export works in ES6 to be able to use all the libs you want and structure your own code in independent module files.

Then, to get the distance between two points with Geolib, you need to use the getDistance function, which takes 2 objects as parameters.

// Function signature from the documentation:
geolib.getDistance(object start, object end[, int accuracy, int precision])

In your case:

// Using destructuring here just to avoid repetition.
const { latitude, longitude } = this.state;

const dist = geolib.getDistance(
  { latitude, longitude },
  { latitude: item.LatL, longitude: item.Long2 }
);

Also note that:

Return value is always float and represents the distance in meters.

To convert it to miles, you could multiply the result by 0.000621.

<Text style={styles.AddressSpace}>Miles: {dist * 0.000621}</Text>

Ideally, I would put the 0.000621 magic number inside a clearly defined constant somewhere.

Or just use the geolib.convertUnit function.

<Text style={styles.AddressSpace}>Miles: {geolib.convertUnit('mi', dist)}</Text>

Try:

import { getDistance } from "geolib"

and then using:

const dist = getDistance(...)

I had a similar issue with puteDestinationPoint(...)

本文标签： javascriptHow to import geolib in React Native to calculate the distance between two pointsStack Overflow