从 Geojson 数组中删除旧版本答案

【问题标题】：Remove older versions from a Geojson array从 Geojson 数组中删除旧版本
【发布时间】：2017-11-16 17:36:42
【问题描述】：

我有一个大的 geojson 文件，其一般结构如下：

{
  "features": [{
      "geometry": {
        "coordinates": [
          [
            [-12.345, 26.006],
            [-78.56, 24.944],
            [-76.44, 24.99],
            [-76.456, 26.567],
            [-78.345, 26.23456]
          ]
        ],

        "type": "Polygon"
      },

      "id": "Some_ID_01",

      "properties": {
        "parameters": "elevation"
      },
      "type": "Feature"
    },

    {
      "geometry": {
        "coordinates": [
          [
            [139.345, 39.2345],
            [139.23456, 37.3465],
            [141.678, 37.7896],
            [141.2345, 39.6543],
            [139.7856, 39.2345]
          ]
        ],
        "type": "Polygon"
      },
      "id": "Some_OtherID_01",
      "properties": {
        "parameters": "elevation"
      },
      "type": "Feature"
    }, {
      "geometry": {
        "coordinates": [
          [
            [143.8796, -30.243],
            [143.456, -32.764],
            [145.3452, -32.76],
            [145.134, -30.87],
            [143.123, -30.765]
          ]
        ],
        "type": "Polygon"
      },
      "id": "Some_ID_02",
      "properties": {
        "parameters": "elevation"
      },
      "type": "Feature"
    }
  ],
  "type": "FeatureCollection"
}

我正在尝试删除重复的 ID，并保留最新版本（即 Some_ID_01 和 Some_ID_02 出于我的目的被认为是重复的，我想保留 Some_ID_02）。这些“重复”的内容没有任何顺序（尽管如果我可以在此过程中对它们进行排序，可能会按字母顺序排列，那就太好了），这些重复也不一定包含相同的坐标值（它们是较新版本的同一点）

到目前为止，我已经阅读了一些删除重复的 json 条目（特别是尝试从 this guide here 修改代码），但我不知道足够的 JS 来修改它以满足我的特定需求。我正在阅读 underscore.js 以查看是否有帮助（基于其他线程中的建议），并且还将查看 python 或 excel（作为 CSV 文件）以查看其中是否有任何简化。

是否可以将 geojson 输入到程序中并获得一个文件作为回报（即使它是一个文本文件）还是内联输入它会更简单？

【问题讨论】：

标签： javascript python excel duplicates geojson

【解决方案1】：

我选择使用 python，因为我更擅长这种语言。我将在下面发布我的代码以供参考，但您也可以找到我在here 发布的另一篇文章，其中详细介绍了我在使用列表从字典中删除键时遇到的问题

import json

json_file = open('features.json')
json_str = json_file.read()
json_data = json.loads(json_str)

dictionaryOfJsonId = {}
removalCounter = 0
keyToRemove = []
valueToRemoveFromList = []
IDList = []

for values in json_data['features']:    #This loop converts the values in the json parse into a dict of only ID
    stringToSplit = values["id"]        #the id values from the json file
    IDList.append(stringToSplit)        #list with all the ID
    newKey = stringToSplit[:-2]         #takes the initial substring up to the last 2 spaces (version)
    newValue = stringToSplit[-2:]       #grabs the last two characters of the string

    if newKey in dictionaryOfJsonId:
        dictionaryOfJsonId[newKey].append(newValue)
    else:
        dictionaryOfJsonId[newKey] = [newValue]


for key in dictionaryOfJsonId:          #Remove entries that do not have duplicates
    if len(dictionaryOfJsonId[key])<2:
        valueToRemoveFromList.append(str(key + dictionaryOfJsonId[key][0]))
    else:
        valueToRemoveFromList.append(str(key +max(dictionaryOfJsonId[key])))


for string in valueToRemoveFromList:    #Remove all values that don't have duplicates from the List of ID
    IDList.remove(string)
    removalCounter+=1


good_features = [i for i in json_data['features'] if i['id'] not in IDList] #Loops through the original and 
                                                                            #removes keys on list from original JSON


with open('features.geojson','w') as outfile:   #create JSON file from list
    json.dump(good_features,outfile)



print "Removed",len(json_data['features'])-removalCounter, "entries from JSON"

【讨论】：