Buffering a feature

Buffering a feature creates a polygon around a feature as a selection geometry or just a simple visualization. In this recipe, we'll buffer a point in a point feature and add the returned polygon geometry to the map.

Getting ready

Once again, we'll use the same New York City Museums layer. You can download the layer from https://github.com/GeospatialPython/Learn/raw/master/NYC_MUSEUMS_GEO.zip.

Unzip that file and place the shapefile's contents in a directory named nyc within your qgis_data directory, within your root or home directory.

How to do it...

This recipe involves both a spatial operation and multiple visualizations. To do this, perform the following steps:

1. First, load the layer:

           lyr = QgsVectorLayer("/qgis_data/nyc/NYC_MUSEUMS_GEO.shp",
                 "Museums", "ogr") 
   

2. Next, visualize the layer on the map:

           QgsMapLayerRegistry.instance().addMapLayers([lyr]) 
   

3. Access the layer's features:

           fts = lyr.getFeatures() 
   

4. Grab the first...