我有一个geojson文件，我想知道从特定字段获取最大值和最小值。 这是我的geojson文件：
var commune = {"type": "FeatureCollection","features": [{
"type": "Feature",
"id":"",
"properties":
{
"nom":"Ain (01)",
"CODE_DEPT":"01",
"MARIE_2007":"242937",
"CELIB_2007":"150068",
"VEUF_2007":"31475",
"DIVOR_2007":"32177",
"MARIE_2011":"248332",
"CELIB_2011":"162880",
"VEUF_2011":"32059",
"DIVOR_2011":"36617",
"P11_POP":"603827",
"P07_POP":"574391",
"NAIS12":"7242",
"NAIS11":"7265",
"DECE12":"4577",
"DECE11":"4305",
"ENCTOT11":"4329",
"ENCTOT10":"4828",
"ENNTOT11":"27186"
},
"geometry": {
"type": "Polygon",
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}
}, {
"type": "Feature",
"id":"",
"properties":
{
"nom":"Allier (03)",
"CODE_DEPT":"03",
"MARIE_2007":"142567",
"CELIB_2007":"94352",
"VEUF_2007":"30977",
"DIVOR_2007":"22520",
"MARIE_2011":"136735",
"CELIB_2011":"97444",
"VEUF_2011":"30224",
"DIVOR_2011":"24318",
"P11_POP":"342729",
"P07_POP":"343124",
"NAIS12":"3288",
"NAIS11":"3196",
"DECE12":"4346",
"DECE11":"4221",
"ENCTOT11":"1934",
"ENCTOT10":"2311",
"ENNTOT11":"15148"
},
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}
}, {
"type": "Feature",
"id":"",
"properties":
{
"nom":"Alpes-de-Haute Provence (04)",
"CODE_DEPT":"04",
"MARIE_2007":"64195",
"CELIB_2007":"41983",
"VEUF_2007":"11250",
"DIVOR_2007":"11881",
"MARIE_2011":"64385",
"CELIB_2011":"45210",
"VEUF_2011":"11200",
"DIVOR_2011":"13050",
"P11_POP":"160959",
"P07_POP":"156071",
"NAIS12":"1561",
"NAIS11":"1578",
"DECE12":"1674",
"DECE11":"1657",
"ENCTOT11":"1688",
"ENCTOT10":"1854",
"ENNTOT11":"11459"
},
"geometry": {
"type": "Polygon",
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]]
}}]};
如果您有任何输入来获取“P11_POP”字段的最大值和最小值，那将非常有用。
我已经尝试过这个功能，但我一定错过了一些东西：
function getMax(commune, prop) {
var max;
for (var i=0 ; i<commune.length ; i++) {
if (!max || parseInt(commune[i][prop]) > parseInt(max[prop]))
max = commune[i];
}
return max;
}
var maxPpg = getMax(commune.features.properties, "P11_POP");
console.log(maxPpg.nom);
谢谢
答案 0 :(得分：3)
这里存在许多问题（特别是Adrian May指出的问题）。我重写了这个函数，让你知道如何修复它。然而，由于硬编码的“属性”字符串，它不再是一般功能。我还使用了Math.max函数来实现更简单：
function getMax(commune, prop) {
var max = -10000000;
for (var i=0 ; i<commune.length ; i++) {
max = Math.max(parseInt(commune[i]["properties"][prop]), max);
}
return max;
}
var maxPpg = getMax(commune.features, "P11_POP");
alert(maxPpg);
答案 1 :(得分：0)
你想要commune.features [i] .properties。各种各样的commune.features.something和commune [i]
commune.features.map( function (i) { return i.properties.POP11 })
为您提供了一个可以添加的整数列表。
答案 2 :(得分：0)
使用Underscore.js可以轻松搞定。
_.max(commune.features, function(feature) {
return parseInt(feature.properties.P11_POP)
})
这将返回整个对象。你可以从中提取你想要的东西;没有必要重新发明轮子。 min函数会为您提供最低价值。