I'm trying to clip a soil use shapefile, with a polygon I've created this morning. The clipping function works, but the clipped polygon doesn't have features (the table of contents is empty). QGIS advices me that:
*Created output shapefile: /Users/biaginisandra/Desktop/Uso_suolo_Roncacce/Uso_suolo_Roncacce.shp Warnings: Input CRS error: One or more input layers missing coordinate reference information, results may not be as expected. GEOS geoprocessing error: One or more input features have invalid geometry. Some output geometries may be missing or invalid. Would you like to add the new layer anyway?*
Where is the problem?
Thanks in advance.