When we look at the scale of a city, we can characterize it using spatial metrics. These are also called landscape metrics or when applied to cities, urban metrics.
In QGIS we can use the LecoS plugin.
1. Install the LecoS plugin from the Plugins Manager.
2. Click 
to go open the Processing Toolbox panel
3. Expand the LecoS group and then the Landcape statistics group.
In the next section, we'll explore these tools.