有效的Topojson和https://mapshaper.org/

Question

所有3种情况都在jsonlint中进行验证，但只有第一种情况在mapshaper中显示。

我不明白为什么没有显示案例2和3。

那么，我如何使用“-”来设置这个正确的属性呢？

1. 在https://mapshaper.org/中显示OK

    {"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]]]
    }

1. 不显示在https://mapshaper.org/中

    {"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]]
    ]
    }

1. 不显示在https://mapshaper.org/中

    {"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

对负(/reversed)弧有错误的索引：

每个弧必须由基于数字零的索引引用到包含拓扑的弧数组中.例如，0代表第一个弧，1代表第二个弧，依此类推。 负弧指数表示，要重建几何形状，必须反转指数的补数处的弧：-1指第一反弧，-2指反向第二弧，以此类推。在JavaScript中，可以使用位非运算符~i (文档)否定负弧索引i。

而不是-0，您应该使用-1。因此，您的第二个topojson示例应该如下所示：

{"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]]
        ]
}