json - 如何向 topojson 文件添加属性？

Question

给定一个 data.tsv 文件:

id  code    name
1   AL  Alabama
2   AK  Alaska
4   AZ  Arizona
5   AR  Arkansas
6   CA  California
... ... ...

给定一个 topojson.json 文件: (结构正确，数值随机)

{ 
"type":"Topology",
"transform": 
    {
    "scale": [0.0015484881821515486,0.0010301030103010299],
    "translate":[-5.491666666666662,41.008333333333354]
    },
"objects": 
    {
    "states":
        {
        "type":"GeometryCollection",
        "geometries": 
            [
            {"type":"Polygon","arcs":[[0]],"properties":{"code_2":"AL"}},
            {"type":"Polygon","arcs":[[1]],"properties":{"code_2":"AK"}}
            ]
        }
    },
"arcs":
    [
        [[2466,9916],[-25,-5],[3,-13]],
        [[2357,9852],[1,-2],[1,-2]]
    ]
}

如何使用公共(public)字段(1)将另一个字段(2)的值注入(inject)到 json 文件中？

1]: data.txt#code和 topojson.txt.objects.states.geometries.properties.code_2
2]: data.txt#name
最终结果应包含:

            {"type":"Polygon","arcs":[[0]],"properties":{"code_2":"AL", "name":"Alabama" }},
            {"type":"Polygon","arcs":[[1]],"properties":{"code_2":"AK", "name":"Alaska" }},

编辑:接受的答案:

topojson -o final.json -e data.tsv --id-property=code_2,code -p code_2,state=name -- topojson.json

Answer 1

尝试使用这个:

topojson -o final.json -e data.tsv --id-property=code_2,code -p code_2,state=name -- topojson.json

哪个应该输出:

{
    "type": "Topology",
    "transform": {
        "scale": [
            0.000016880209206372492,
            0.000007005401010148724
        ],
        "translate": [
            -1.8418800213354616,
            51.15278777877789
        ]
    },
    "objects": {
        "states": {
            "type": "GeometryCollection",
            "geometries": [
                {
                    "type": "Polygon",
                    "arcs": [
                        [
                            0
                        ]
                    ],
                    "id": "AK",
                    "properties": {
                        "code_2": "AK",
                        "state": "Alaska"
                    }
                }
            ]
        }
    },
    "arcs": [
        [
            [
                0,
                588
            ],
            [
                92,
                -294
            ],
            [
                91,
                -294
            ],
            [
                -183,
                588
            ]
        ]
    ]
}

来自 Command Line Reference wiki :

--id-property name of feature property to promote to geometry id

通过使用 code_2使用此选项的属性，您将其提升为功能 ID。

Prepend a + in front of the input property name to coerce its value to a number.

加:

If the properties referenced by --id-property are null or undefined, they are omitted from the output geometry object. Thus, the generated objects may not have a defined ID if the input features did not have a property with the specified name.

所以，当你使用 +code和 +code_2 ，他们可能是 undefined ，因为您无法转换 AK将字符串值转换为数字。

Here, the input property "FIPS" is coerced to a number and used as the feature identifier; likewise, the column named "FIPS" is used as the identifier in the CSV file. (If your CSV file uses a different column name for the feature identifier, you can specify multiple id properties, such as --id-property=+FIPS,+id.)

这就是为什么您必须添加 code到 --id-property=code_2,code选项。这就是映射的制作方式(topojson.json 中的 code_2 和 data.tsv 中的 code 列)。

Then, the output property "unemployment" is generated from the external data file, unemployment.tsv, which defines the input property "rate"

在我们的例子中， -p code_2,state=name指定我们将保留 code_2属性，我们将重命名 name属性(property)给 state . 房产 和 外部属性 上述文档 wiki 中的部分对此事提供了相当丰富的信息。