turf. JS usage

1. stay index.html Direct reference

 <script src="https://unpkg.com/@turf/[email protected]/turf.min.js"></script>

2. Use directly where necessary turf object ,turf It is mainly used to calculate the relationship between spatial geometric objects , spot 、 Line 、 Include between faces 、 Intersection and other systematic operations .
Please refer to turf.js Chinese net ：https://turfjs.fenxianglu.cn/category/#cdn%E5%BC%95%E5%85%A5

3. Determine whether the point is within the polygon range

  let pt = turf.point([103.30749303102493, 29.789869635742235]);
  let coordinates = [...];// Polygon data 
  let poly;
  if(coordinates.length>1){
    
    // solve 'Each LinearRing of a Polygon must have 4 or more Positions.' error 
    poly = turf.multiPolygon(coordinates);
  }else{
    
    poly = turf.polygon(coordinates);
  }
  let isIncluded = turf.booleanPointInPolygon(pt, poly)

Polygon data format :

3. Get the center point of the polygon range

let poly;
let coordinates = [...];// Polygon data 
if(coordinates.length>1){
    
// solve 'Each LinearRing of a Polygon must have 4 or more Positions.' error 
    poly = turf.multiPolygon(coordinates );
}else{
    
    poly = turf.polygon(coordinates );
}
let centerPoint = turf.centerOfMass(poly); // Get the coordinates of the center point of the polygon 
console.log(centerPoint)

4. Get a series of points and the absolute center point of the polygon

let areaArr = areaData.map(item=>item.geometry.coordinates);
        let pointArr = pointData.map(item=>item.geometry.coordinates);
        let centerPoint;
        if(areaArr.length){
    
            centerPoint = turf.centroid(turf.multiPolygon([...areaArr, ...pointArr]))
        }else{
    
            centerPoint = turf.center(turf.featureCollection(
                pointArr.map(item=>turf.point(item))
            ))
        }

let areaCoordinates = [...];// Polygon data 
let pointCoordinates = [...];// Point data 
let centerPoint;
if(areaCoordinates.length){
    // Determine whether there are polygons 
   centerPoint = turf.centroid(turf.multiPolygon([...areaCoordinates , ...pointCoordinates ]))
}else{
    
   centerPoint = turf.center(turf.featureCollection(
                pointCoordinates.map(item=>turf.point(item))
            ))
}
console.log(centerPoint)