有效的 Topojson 和 https://mapshaper.org/

Question

所有 3 个案例都在 jsonlint 中验证，但只有第一个案例显示在 mapshaper 中。

我不明白为什么案例2和案例3没有显示。

那么我如何在属性的 arcs ref 中使用'-'来设置这个正确的？

在 https://mapshaper.org/

    {"type":"Topology", "crs":{"type":"name","properties":{"name":"EPSG:25832"}},"objects":{"collection": { "type": "GeometryCollection", "geometries":[
    { "type": "MultiPolygon", "arcs": [[[0,1]]],"properties":{"id":9005309}}]}},"arcs": 
    [
    [[565546,7786890.97],[565545.69,7786859.81]],
    [[565545.69,7786859.81],[565545.06,7786876.95],[565546,7786890.97]]]
    }

不显示在 https://mapshaper.org/


    {"type":"Topology", "crs":{"type":"name","properties":{"name":"EPSG:25832"}},"objects":{"collection": { "type": "GeometryCollection", "geometries":[
    { "type": "MultiPolygon", "arcs": [[[-0,-1]]],"properties":{"id":9005309}}]}},"arcs":
    [
    [[565545.69,7786859.81],[565546,7786890.97]],
    [[565546,7786890.97],[565545.06,7786876.95],[565545.69,7786859.81]]
    ]
    }

不显示在 https://mapshaper.org/

    {"type":"Topology", "crs":{"type":"name","properties":{"name":"EPSG:25832"}},"objects":{"collection": { "type": "GeometryCollection", "geometries":[
    { "type": "MultiPolygon", "arcs": [[[-0,1]]],"properties":{"id":9005309}}]}},"arcs": 
    [
    [[565545.69,7786859.81],[565546,7786890.97]],
    [[565545.69,7786859.81],[565545.06,7786876.95],[565546,7786890.97]]]
    }

Answer 1

负（/反）弧的索引错误：

Each arc must be referenced by numeric zero-based index into the containing topology’s arcs array. For example, 0 refers to the first arc, 1 refers to the second arc, and so on.

A negative arc index indicates that the arc at the ones’ complement of the index must be reversed to reconstruct the geometry: -1 refers to the reversed first arc, -2 refers to the reversed second arc, and so on. In JavaScript, you can negate a negative arc index i using the bitwise NOT operator, ~i. (docs)

您应该使用 -1 而不是 -0。因此，您的第二个 topojson 示例应绘制如下：

{"type":"Topology", 
        "crs":{"type":"name","properties": {"name":"EPSG:25832"}},
        "objects":{
        "collection": { "type": "GeometryCollection", 
             "geometries":[
                   { "type": "MultiPolygon", 
                     "arcs": [[[-1,-2]]],
                     "properties":{"id":9005309}}]}},
        "arcs":[
              [[565545.69,7786859.81],[565546,7786890.97]],
              [[565546,7786890.97],[565545.06,7786876.95],[565545.69,7786859.81]]
        ]
}

有效的 Topojson 和 https://mapshaper.org/

Valid Topojson and https://mapshaper.org/

topojson