从csv创建GeoJson:如何设置几何属性？

Question

我有一个csv文件,我想转换为GeoJson.

lon,lat,val,id
-97.1589432,25.9642008,0,2690
-97.1682294,25.9761856,0,2691
-97.1775156,25.9881704,0,2692

我运行以下ogr2ogr命令

ogr2ogr -f GEOJson geo_result.json source.csv

我得到了这个结果

{
"type": "FeatureCollection",

"features": [
{ "type": "Feature", "properties": { "lon": "-97.1589432", "lat": "25.9642008", "val": "0", "id": "2690" }, "geometry": null },
{ "type": "Feature", "properties": { "lon": "-97.1682294", "lat": "25.9761856", "val": "0", "id": "2691" }, "geometry": null },
{ "type": "Feature", "properties": { "lon": "-97.1775156", "lat": "25.9881704", "val": "0", "id": "2692" }, "geometry": null }
]
}

为什么几何为零？我怎么能告诉ogr2ogr哪些值是lat&lon？

Answer 1

您需要将CSV文件包装在VRT指定列含义的文件中.

<OGRVRTDataSource>
    <OGRVRTLayer name="source">
        <SrcDataSource>source.csv</SrcDataSource>
        <GeometryType>wkbPoint</GeometryType>
        <LayerSRS>WGS84</LayerSRS>
        <GeometryField encoding="PointFromColumns" x="lon" y="lat"/>
    </OGRVRTLayer>
</OGRVRTDataSource>

然后使用该VRT文件作为输入:

ogr2ogr -f GEOJson geo_result.json source.vrt

QGIS(使用OGR)有一个巧妙地猜测列的界面,并且非常有效.因此,如果您只需使用转换一次,则可能需要使用QGIS等GUI进行转换.

有关CSV详细信息,请参阅OGR 的驱动程序页面:http: //www.gdal.org/ogr/drv_csv.html