我有一个数组（Geojson 文件），我想将它分成三个数组。有一些多边形坐标，我想为每个 id 放置连续的坐标，我想得到： arrGeo = [ [-4.66478, 58.42441, 5127.4,-4.65982, 58.42082, 5074.7], [-3.94815, 57.71632, 5000,-3.94812, 57.71576, 4374.1,-3.94216, 57.71541, 4283,-3.93717, 57.71583, 5001], [-3.93224, 57.71476, 4048,-3.93261, 57.71456, 3800.4] ]我尝试通过使用 for 循环来做到这一点，但我无法将它们分开，我的意思是我需要为每个 ID 创建单独的坐标数组。我的代码有什么问题？我应该怎么做才能解决它？这是我的代码：positions = [ { "type": "Feature", "geometry": { "type": "GeometryCollection", "geometries": [ { "type": "Polygon", "coordinates": [ [ [-4.66478, 58.42441, 5127.4], [-4.65982, 58.42082, 5074.7], ] ] }, ] }, "id": "kml_1" }, { "type": "Feature", "geometry": { "type": "GeometryCollection", "geometries": [ { "type": "Polygon", "coordinates": [ [ [-3.94815, 57.71632, 5000], [-3.94812, 57.71576, 4374.1], ] ] }, { "type": "Polygon", "coordinates": [ [ [-3.94216, 57.71541, 4283], [-3.93717, 57.71583, 5001], ] ] }, ] }, "id": "kml_2" },
4 回答
MMTTMM
TA贡献1869条经验 获得超4个赞
let final = [];
for (var i = 0, len = positions.length; i < len; i++) {
let a = [];
for (var j = 0, jlen = positions[i]["geometry"]["geometries"].length; j < jlen; j++) {
for (var k = 0, klen = positions[i]["geometry"]["geometries"][j]["coordinates"].length; k < klen; k++) {
for (l = 0, llen = positions[i]["geometry"]["geometries"][j]["coordinates"][k].length; l < llen; l++) {
a = a.concat(positions[i]["geometry"]["geometries"][j]["coordinates"][k][l]);
}
}
}
final.push(a);
}
console.log(final);
SMILET
TA贡献1796条经验 获得超4个赞
您可以使用 forEach 来实现，以获得更好的性能。
let positions = [
{
type: "Feature",
geometry: {
type: "GeometryCollection",
geometries: [
{
type: "Polygon",
coordinates: [
[
[-4.66478, 58.42441, 5127.4],
[-4.65982, 58.42082, 5074.7],
],
],
},
],
},
id: "kml_1",
},
{
type: "Feature",
geometry: {
type: "GeometryCollection",
geometries: [
{
type: "Polygon",
coordinates: [
[
[-3.94815, 57.71632, 5000],
[-3.94812, 57.71576, 4374.1],
],
],
},
{
type: "Polygon",
coordinates: [
[
[-3.94216, 57.71541, 4283],
[-3.93717, 57.71583, 5001],
],
],
},
],
},
id: "kml_2",
},
{
type: "Feature",
geometry: {
type: "GeometryCollection",
geometries: [
{
type: "Polygon",
coordinates: [
[
[-3.93224, 57.71476, 4048],
[-3.93261, 57.71456, 3800.4],
],
],
},
],
},
id: "kml_3",
},
];
let newPolygons = []
const flatPositions = (arr)=>{
arr.forEach((pos)=>{
let p = []
pos?.geometry?.geometries.forEach((geometry)=>{
geometry?.coordinates.forEach(coord=>{
coord.forEach(coo=>{
p = p.concat(coo)
})
})
})
newPolygons.push(p)
})
}
flatPositions(positions)
console.log(newPolygons)
噜噜哒
TA贡献1784条经验 获得超7个赞
只需使用Array.prototype.reduce()
和Array.prototype.flat()
以及解构赋值
const arrGeo = positions.reduce((a,{geometry})=>
{
let item = []
for (let geo of geometry.geometries)
{
let p = geo.coordinates.reduce((t,c)=>
{
t.push(...c.flat())
return t
},[])
item.push(...p)
}
a.push(item)
return a
},[])
完整代码：
const positions =
[ { type: 'Feature'
, geometry:
{ type: 'GeometryCollection'
, geometries:
[ { type: 'Polygon'
, coordinates:
[ [ [ -4.66478, 58.42441, 5127.4]
, [ -4.65982, 58.42082, 5074.7]
] ] } ] }
, id: 'kml_1'
}
, { type: 'Feature'
, geometry:
{ type: 'GeometryCollection'
, geometries:
[ { type: 'Polygon'
, coordinates:
[ [ [ -3.94815, 57.71632, 5000 ]
, [ -3.94812, 57.71576, 4374.1 ]
] ] }
, { type: 'Polygon'
, coordinates:
[ [ [ -3.94216, 57.71541, 4283]
, [ -3.93717, 57.71583, 5001]
] ] } ] }
, id: 'kml_2'
}
, { type: 'Feature'
, geometry:
{ type: 'GeometryCollection'
, geometries:
[ { type: 'Polygon'
, coordinates:
[ [ [ -3.93224, 57.71476, 4048]
, [ -3.93261, 57.71456, 3800.4]
] ] } ] }
, id: 'kml_3'
} ]
const arrGeo = positions.reduce((a,{geometry})=>
{
let item = []
for( let geo of geometry.geometries )
{
let p = geo.coordinates.reduce((t,c)=>
{
t.push(...c.flat())
return t
},[])
item.push(...p)
}
a.push(item)
return a
},[])
arrGeo.forEach(el=> console.log(JSON.stringify(el)))
.as-console-wrapper { max-height: 100% !important; top: 0; }
慕莱坞森
TA贡献1810条经验 获得超4个赞
我不确定，但如果我理解正确，这应该是理想的结果。我希望我有所帮助。
positions =
[
{
"type": "Feature",
"geometry": {
"type": "GeometryCollection",
"geometries": [
{
"type": "Polygon",
"coordinates": [
[
[-4.66478, 58.42441, 5127.4],
[-4.65982, 58.42082, 5074.7],
]
]
},
]
},
"id": "kml_1"
},
{
"type": "Feature",
"geometry": {
"type": "GeometryCollection",
"geometries": [
{
"type": "Polygon",
"coordinates": [
[
[-3.94815, 57.71632, 5000],
[-3.94812, 57.71576, 4374.1],
]
]
},
{
"type": "Polygon",
"coordinates": [
[
[-3.94216, 57.71541, 4283],
[-3.93717, 57.71583, 5001],
]
]
},
]
},
"id": "kml_2"
},
{
"type": "Feature",
"geometry": {
"type": "GeometryCollection",
"geometries": [
{
"type": "Polygon",
"coordinates": [
[
[-3.93224, 57.71476, 4048],
[-3.93261, 57.71456, 3800.4],
]
]
},
]
},
"id": "kml_3"
},
];
var arrGeo = [];
var res = [];
for (var i = 0; i < positions.length; i++) {
var x = positions[i].geometry.geometries;
var f = [];
for (var ii = 0; ii < x.length; ii++) {
var z = x[ii].coordinates[0];
var t = z.flat();
f.push(t)
}
res.push(f);
for (let ii = 0; ii < res.length; ii++) {
res[ii].flat();
}
}
for (var i = 0; i < res.length; i++) {
arrGeo.push(res[i].flat());
}
console.log(arrGeo);
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