如何使用JSTS Library计算Google Maps API中的交叉区域？ [英] How to calculate intersection area in Google Maps API with JSTS Library?

问题描述

我试图计算两个三角形之间的交点的面积。
我发现 JSTS Topology Suite 有一个几何类其中一个方法 intersection（）。
我在 JSFiddle 和我的本地计算机上尝试过它，但是我得到了一个 Uncaught TypeError：undefined不是函数。
JSTS还有一个示例。在这里你可以看到代码。
我的代码在JSFiddle中看起来相同：

  var union = triangleCoords.union（secondTriangleCoords）; 
 var intersection = triangleCoords.intersection（secondTriangleCoords）; 
 console.log（'Intersection'+ intersection）; 
 google.maps.geometry.spherical.computeArea（intersection）; 
  

是否有转换我也应该做？

解决方案

一般的答案是，您需要将google.maps.Polygon对象转换为jsts.geom.Geometry对象，然后运行联合。如果您想在Google Maps JavaScript API v3地图上显示结果，则需要将返回的jsts.geom.Geometry对象转换回google.maps.Polygon。

此代码（来自此问题）将转换路径转换为jstsPolygon：

  var coordinates = googleMaps2JTS（googlePolygonPath）; 
 var geometryFactory = new jsts.geom.GeometryFactory（）; 
 var shell = geometryFactory.createLinearRing（coordinates）; 
 var jstsPolygon = geometryFactory.createPolygon（shell）; 
  

类似于此：

  var geometryFactory = new jsts.geom.GeometryFactory（）; 
 
 var trito = bermudaTriangle.getPath（）; 
 var tritoCoor = googleMaps2JTS（trito）; 
 var shell = geometryFactory.createLinearRing（tritoCoor）; 
 
 var trito2 = secondBermuda.getPath（）; 
 var tritoCoor2 = googleMaps2JTS（trito2）; 
 var shell2 = geometryFactory.createLinearRing（tritoCoor2）; 
 
 var jstsPolygon = geometryFactory.createPolygon（shell）; 
 var jstsPolygon2 = geometryFactory.createPolygon（shell2）; 
 
 var intersection = jstsPolygon.intersection（jstsPolygon2）; 
  

jsfiddle

然而，要在结果上使用computeArea方法，您需要将其转换回数组或MVCArray。 maps.LatLng对象（ computeArea（path：Array。| MVCArray。，radius ?:数字））

或者您可以使用[jsts.geom.Polygon.getArea]（ http://bjornharrtell.github.io/jsts/doc/api/symbols/jsts.geom.Polygon .html＃getArea ）方法。

工作小提琴与三角形，联合和交叉点的区域使用jsts方法。

将结果转换回google.maps.LatLng和google的代码。 maps.Polyg对象：

  var jsts2googleMaps =函数（几何）{
 var coordArray = geometry.getCoordinates（）; 
 GMcoords = []; 
 for（var i = 0; i< coordArray.length; i ++）{
 GMcoords.push（new google.maps.LatLng（coordArray [i] .x，coordArray [i] .y） ）; 
} 
返回GMcoords; 
} 
 
 var intersectionGMArray = jsts2googleMaps（intersection）; 
  

然后获得区域：

  var intersectionGMarea = google.maps.geometry.spherical.computeArea（intersectionGMArray）; 
  

工作小提琴

I am trying to calculate the area of the intersection between two triangles. I found out the JSTS Topology Suite has a Geometry class which a method intersection(). I tried it on JSFiddle and on my local computer but i am getting an Uncaught TypeError: undefined is not a function. There is also an example from JSTS. Here you can see the code. My code looks the same in JSFiddle:

var union = triangleCoords.union(secondTriangleCoords);
var intersection = triangleCoords.intersection(secondTriangleCoords);
console.log('Intersection ' + intersection);
google.maps.geometry.spherical.computeArea(intersection);

Is there a conversion that i should do also?

解决方案

The general answer is you need to convert the google.maps.Polygon objects into jsts.geom.Geometry objects, then run the union. If you want to display the result on a Google Maps Javascript API v3 map, then you need to convert the returned jsts.geom.Geometry object back into a google.maps.Polygon.

This code (from this question) converts a path into a jstsPolygon:

var coordinates = googleMaps2JTS(googlePolygonPath);
var geometryFactory = new jsts.geom.GeometryFactory();
var shell = geometryFactory.createLinearRing(coordinates);
var jstsPolygon = geometryFactory.createPolygon(shell);

Something like this:

var geometryFactory = new jsts.geom.GeometryFactory();

var trito = bermudaTriangle.getPath();
var tritoCoor = googleMaps2JTS(trito);
var shell = geometryFactory.createLinearRing(tritoCoor);

var trito2 = secondBermuda.getPath();
var tritoCoor2 = googleMaps2JTS(trito2);
var shell2 = geometryFactory.createLinearRing(tritoCoor2);

var jstsPolygon = geometryFactory.createPolygon(shell);
var jstsPolygon2 = geometryFactory.createPolygon(shell2);

var intersection = jstsPolygon.intersection(jstsPolygon2);

jsfiddle

To use the computeArea method on the result, though, you need to convert it back into an array or an MVCArray of google.maps.LatLng objects (computeArea(path:Array.|MVCArray., radius?:number))

Or you could use the [jsts.geom.Polygon.getArea] (http://bjornharrtell.github.io/jsts/doc/api/symbols/jsts.geom.Polygon.html#getArea) method.

working fiddle with area of triangles, union and intersection using the jsts method.

Code to convert the results back to google.maps.LatLng and google.maps.Polygon objects:

var jsts2googleMaps = function (geometry) {
  var coordArray = geometry.getCoordinates();
  GMcoords = [];
  for (var i = 0; i < coordArray.length; i++) {
    GMcoords.push(new google.maps.LatLng(coordArray[i].x, coordArray[i].y));
  }
  return GMcoords;
}

var intersectionGMArray = jsts2googleMaps(intersection);

Then to get the area:

var intersectionGMarea = google.maps.geometry.spherical.computeArea(intersectionGMArray);

working fiddle

这篇关于如何使用JSTS Library计算Google Maps API中的交叉区域？的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！