AlwaysBeBlue wrote:20191010_163744.jpg
If you click on the picture to expand
If you look at the map, the large area of green space close to the City Centre between Ely and Llandough.
If you look to the other side of Cardiff, there are plenty of houses and more being built. I will upload a map of this side as well
If you're referring to the area south of the A4232 then it comes under the Vale of Glamorgan council rather than Cardiff.
The way the city has grown over the decades is by local governemnt boundary changes bringing semi-rural areas from ajoining authorities inside the city boundaries which are then gradually developed.
Until 1938, for instance, the eastern boundary of the city was the river Rhymney. It was only after the 1938 boundary change that places like Rhymney, Llanrhumney, New Saint Mellons etc began to grow.
Similarly Llandaff, Rhiwbina and Whichurch became part of the city in the 1960's enabling developments like Danescourt, Pantmawr etc.
The last such change was in 1996 when the city expanded to include Creigiau and Pentyrch. That change is what has lead to the Plasdwr development.
The area you identify could become part of the city in future although Leckwith Ridge and wood provide a pretty formidable barrier to integrating it easily with the rest of the city.
Personally, I think Penarth should be a part of the city but you enter a whole world of pain if you tell Penarth people that!