I am working with QGIS 2.12.3 Lyon. I have a shapefile which contains slope data for a large territory (layer - PenteSZ32). I want to lighten the weight of my shapefile by clipping it to a narrower surface that correspond to my study area. My study area correspond to a ripperian buffer of 1000 meters (layer - Donut_buffer_1000m).
In order to clip my polygon, i used the Vector > Geoprocessing Tools > Clipper as shown in the following image. This request worked previously with other layers. However, it doensn't work in this case. It bugs at 12 %. Both layer are in the same SCR.
Can you help me figure out what is the problem with my request ? Alternatively, do you have any other way to proceed you could suggest me ?