The "town plan analysis" is a morphological approach, first developed by M. R. G. Conzen, for geographical studies involving urban landscape. In his seminal work on Alnwick (Conzen 1960), Conzen defined town plan (also ground plan or urban layout), land uses, and building fabric as the three basic elements of urban landscape, and discussed their relative importance for urban morphological studies. He argued that urban morphological change is a complicated process due to differential rates at which town plan, buildings, and land use alter their character in keeping with ever-changing functional needs of society. In general, land and building use is subject to relatively rapid changes, while actual building structures are less so (though functional modifications will be frequent) and the urban layout, as defined by streets, open spaces and plots, proves usually to be the most resistant to change. Therefore, he considered the confinement of later developments within preexisting morphological conditions, primarily defined by urban layouts, as one of the fundamental laws in urban landscape studies.