Questions tagged «virtual-layer»

2
使用QGIS虚拟层的多边形相交
我正在尝试通过使用虚拟层来使QGIS中的多边形几何图形相交: SELECT sbqry.rowid AS gid, sbqry.geom FROM (SELECT ST_Intersection(land_parcels.geometry, flood_zone.geometry) AS geom FROM land_parcels, flood_zone WHERE ST_Intersects(land_parcels.geometry, flood_zone.geometry) AND NOT ST_Touches(land_parcels.geometry, flood_zone.geometry)) AS sbqry; 不幸的是,sbqry.rowid AS gid返回NULL而不是自动递增值。 有人知道如何创建名为“ gid”的唯一标识符列吗?据我所知,虚拟层是基于SQLite / Spatialite的。
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