我有个小问题,请帮帮我。我在JSFIDLE中有一个简单的脚本。更具体地说,首先我有一个文本文件,其中包含坐标和每对坐标的id。此文本文件如下所示:
{
"displayFieldName": "",
"fieldAliases": {
"FID": "FID",
"Id": "Id",
"Longtitude": "Longtitude",
"Latitude": "Latitude"
},
"geometryType": "esriGeometryPoint",
"spatialReference": {
"wkid": 4326,
"latestWkid": 4326
},
"fields": [{
"name": "FID",
"type": "esriFieldTypeOID",
"alias": "FID"
}, {
"name": "Id",
"type": "esriFieldTypeInteger",
"alias": "Id"
}, {
"name": "Longtitude",
"type": "esriFieldTypeDouble",
"alias": "Longtitude"
}, {
"name": "Latitude",
"type": "esriFieldTypeDouble",
"alias": "Latitude"
}],
"features": [{
"attributes": {
"FID": 0,
"Id": 1,
"Longtitude": 23.739000000000001,
"Latitude": 37.972000000000001
},
"geometry": {
"x": 23.739000000000001,
"y": 37.972000000000001
}
}, {
"attributes": {
"FID": 1,
"Id": 2,
"Longtitude": 23.760100000000001,
"Latitude": 37.984999999999999
},
"geometry": {
"x": 23.760100000000001,
"y": 37.984999999999999
}
}, {
"attributes": {
"FID": 2,
"Id": 3,
"Longtitude": 23.749199999999998,
"Latitude": 37.975999999999999
},
"geometry": {
"x": 23.749199999999998,
"y": 37.975999999999999
}
}, {
"attributes": {
"FID": 3,
"Id": 4,
"Longtitude": 23.735700000000001,
"Latitude": 37.975999999999999
},
"geometry": {
"x": 23.735700000000001,
"y": 37.975999999999999
}
}]
}
这个文本文件由一个小脚本(在JSFIDLE中)读取,并保存在一个数组“text”中:
<input type='file' accept='text/plain' onchange='openFile(event)'><br>
<img id='output'>
<script>
var openFile = function(event) {
var input = event.target;
var reader = new FileReader();
reader.onload = function(){
var text = reader.result;
console.log(reader.result.substring(0, 200));
console.log(text);
};
reader.readAsText(input.files[0]);
};
</script>
我的问题是:我想为每对坐标添加一个新列,
z
. 此列的计算如下:
z=Longtitude+Latitude
(
long
,
lat
是文本中存在的变量)。所以基本上,我希望在数组“text”中重复一次,在这里我可以计算一个新列,也可以保留旧列(经度、纬度和Id列)。在我看来,我希望将这4列导出到一个新的文本文件中。我希望你能理解我的意思。