Planning the territory presupposes an in-depth knowledge of it and, accordingly, gathering and systematizing information. Such gathering demands territorial delimitation referents. The latter are often administrative boundaries, but these do not always match the reality. In other cases, the territory is subdivided in a geo-referenced grid but available data or the attributes under scrutiny do not always fit such a blind geometry. Determining physical boundaries for data gathering units is a relevant and preliminary issue in any spatial planning process, especially if the territories in question lack homogeneity and/or if the approaches in use demand great detail. This communication intends to summarily present a Methodology for identifying and characterizing local scale territorial units within the Extended City designed during the ongoing research project Costs and Benefits of Urban Dispersion on a Local Scale. The designed methodology conjugates four complementary types of analysis, the first two containing some innovative aspects:

• Digital Method;
• Empirical Knowledge on Cartography;
• Use of Statistical Data;
• Complementary Analyses. Articulating the first three provides Base Land Units (BLUs) and Urban Pieces’ limits and preliminary characterization. These concepts were created and adopted to express local scale realities; BLUs are essentially functional-experiential and Urban Pieces morpho-typological.Complementary Analyses take the delimited units’ characterization further. There may be several types of such analyses depending on the objectives to achieve, which makes way for employing the Methodology in a vast range of situations. The whole Methodology is based on the idea that delimitation and characterization tasks should take place in parallel. They should also relate to each other so that the delimited units express from the onset different realities without preventing that more in-depth knowledge on each of them is sought in subsequent phases.