Question

我有这个坐标数组，最终目标是将彼此之间30分钟之内的坐标分组。

有关如何用Java脚本实现此目标的任何指示？，我正在使用的示例数据如下。

{
  "gps_locations": [{
    "type": "gps_location",
    "properties": {
      "layer": "Features",
      "device": "0",
      "timestamp": "21.08.2018 at 22:45:04",
      "unixtime": 1534891504
    },
    "geometry": {
      "type": "Point",
      "coordinates": [-90.3837, -0.66886666666667]
    }
  }, {
    "type": "gps_location",
    "properties": {
      "layer": "Features",
      "device": "0",
      "timestamp": "21.08.2018 at 16:05:04",
      "unixtime": 1534867504
    },
    "geometry": {
      "type": "Point",
      "coordinates": [-78.494933333333, -0.21085]
    }
  }, {
    "type": "gps_location",
    "properties": {
      "layer": "Features",
      "device": "0",
      "timestamp": "18.01.2018 at 01:32:03",
      "unixtime": 1516239123
    },
    "geometry": {
      "type": "Point",
      "coordinates": [-78.494993333333, -0.20414]
    }
  }, {
    "type": "gps_location",
    "properties": {
      "layer": "Features",
      "device": "0",
      "timestamp": "31.07.2010 at 09:02:48",
      "unixtime": 1280566968
    },
    "geometry": {
      "type": "Point",
      "coordinates": [13.03573045, 47.466879033333]
    }
  }, {
    "type": "gps_location",
    "properties": {
      "layer": "Features",
      "device": "0",
      "timestamp": "31.07.2010 at 07:02:04",
      "unixtime": 1280559724
    },
    "geometry": {
      "type": "Point",
      "coordinates": [13.03573045, 47.466879033333]
    }
  }, {
    "type": "gps_location",
    "properties": {
      "layer": "Features",
      "device": "0",
      "timestamp": "31.07.2010 at 07:02:04",
      "unixtime": 1280559724
    },
    "geometry": {
      "type": "Point",
      "coordinates": [13.03573045, 47.466879033333]
    }
  }]
}

Answer 1

以下是一个可能适合您的版本：

const last = (xs) => xs[xs.length - 1]

const groupByDiff = (diff, period) => (locs) => locs.sort(diff).reduce(
  (all, loc) => {
    if (!all.length || diff(loc, last(last(all))) > period) {
      all.push([])
    }
    last(all).push(loc)
    return all;
  },
  []
)

const toDate = (ts) => new Date(`${ts.slice(6, 10)}-${ts.slice(3, 5)}-${ts.slice(0, 2)}T${ts.slice(14)}`)
const timestampDifference = (a, b) => toDate(a.properties.timestamp) - toDate(b.properties.timestamp)

const input = {"gps_locations": [{"geometry": {"coordinates": [13.03573045, 47.466879033333], "type": "Point"}, "properties": {"device": "0", "layer": "Features", "timestamp": "31.07.2010 at 07:02:04", "unixtime": 1280559724}, "type": "gps_location"}, {"geometry": {"coordinates": [13.03573045, 47.466879033333], "type": "Point"}, "properties": {"device": "0", "layer": "Features", "timestamp": "31.07.2010 at 07:02:04", "unixtime": 1280559724}, "type": "gps_location"}, {"geometry": {"coordinates": [13.03573045, 47.466879033333], "type": "Point"}, "properties": {"device": "0", "layer": "Features", "timestamp": "31.07.2010 at 09:02:48", "unixtime": 1280566968}, "type": "gps_location"}, {"geometry": {"coordinates": [-78.494993333333, -0.20414], "type": "Point"}, "properties": {"device": "0", "layer": "Features", "timestamp": "18.01.2018 at 01:32:03", "unixtime": 1516239123}, "type": "gps_location"}, {"geometry": {"coordinates": [-78.494933333333, -0.21085], "type": "Point"}, "properties": {"device": "0", "layer": "Features", "timestamp": "21.08.2018 at 16:05:04", "unixtime": 1534867504}, "type": "gps_location"}, {"geometry": {"coordinates": [-90.3837, -0.66886666666667], "type": "Point"}, "properties": {"device": "0", "layer": "Features", "timestamp": "21.08.2018 at 22:45:04", "unixtime": 1534891504}, "type": "gps_location"}]}

const groupedLocations = groupByDiff(timestampDifference, 1000 * 60 * 30)(input.gps_locations)
console.log(groupedLocations)

请注意API：函数groupByDiff相当通用，接受一个函数，该函数可以找到两个元素之间的数值差和阈值周期（以毫秒为单位），并返回一个接受对象列表，排序和分组的函数他们根据那个时期。

last是一个简单的辅助函数，可以避免重复xs[xs.length]多次，包括嵌套一次。 toDate使用您的一个时间戳并将其转换为日期。 timestampDifference占据两个位置，获取它们的时间戳，将它们都转换为日期，并求出它们的差（以毫秒为单位）。

最后，groupByDiff是主要功能。我们首先提供timestampDifference和30分钟，然后为结果函数提供原始数据的gps_locations属性，并返回位置列表的列表。

当然，const groupedLocations = groupByDiff(timestampDifference, 1000 * 60 * 30)是一种函数，您可以在拥有此数据结构的任何时间重复使用。 groupByDiff您可以在许多数据结构中重复使用。

如何将坐标按时间戳值分组

1 个答案: