对GeoJSON数据进行过滤

Question

我想知道GeoJSON数据的FeatureCollection通常是如何过滤的。例如，使用以下earthquake data

{
"type": "FeatureCollection",
"crs": { "type": "name", "properties": { "name": "urn:ogc:def:crs:OGC:1.3:CRS84" } },
"features": [
    { "type": "Feature", "properties": { "id": "ak16994521", "mag": 2.3, "time": 1507425650893, "felt": null, "tsunami": 0 }, "geometry": { "type": "Point", "coordinates": [ -151.5129, 63.1016, 0.0 ] } },
    { "type": "Feature", "properties": { "id": "ak16994519", "mag": 1.7, "time": 1507425289659, "felt": null, "tsunami": 0 }, "geometry": { "type": "Point", "coordinates": [ -150.4048, 63.1224, 105.5 ] } },
    { "type": "Feature", "properties": { "id": "ak16994517", "mag": 1.6, "time": 1507424832518, "felt": null, "tsunami": 0 }, "geometry": { "type": "Point", "coordinates": [ -151.3597, 63.0781, 0.0 ] } },
    { "type": "Feature", "properties": { "id": "ci38021336", "mag": 1.42, "time": 1507423898710, "felt": null, "tsunami": 0 }, "geometry": { "type": "Point", "coordinates": [ -118.497, 34.299667, 7.64 ] } },
    { "type": "Feature", "properties": { "id": "hv61900626", "mag": 2.91, "time": 1504833891990, "felt": null, "tsunami": 0 }, "geometry": { "type": "Point", "coordinates": [ -155.011833, 19.399333, 2.609 ] } }
]
}

现在，如果这些数据都在单个FeatureCollection中，那么如何过滤数据，例如使用magnitude > 2.5查看地震？似乎在处理FeatureCollection时，首先要做的是将每个功能提取到它自己的项中:这是通常所做的吗，以便可以查询单个属性？

Answer 1

GeoJSON是一种传输格式，您已经注意到，对它的任何操作都需要每次读取和解析整个文件。如果您计划对数据执行任何操作，则应该将其转换为支持索引的更有用的格式。如果您需要保持基于文件的格式，那么我推荐大多数现代地理信息系统都支持的GeoPackage。或者，您可以使用空间上可用的数据库，比如PostGIS。

在任何一种情况下，转换数据的最简单方法都是使用ogr2ogr