Master Plans, Development Plans & the CDP

A Master Plan (called a Development Plan in Maharashtra and several states, and echoed in the JNNURM-era City Development Plan, or CDP) is the statutory instrument that sets out how a city should grow over roughly the next twenty years. It is prepared under each state's Town and Country Planning Act, put to public objection, and then notified - after which it has the force of law. A building permission that contradicts the notified plan can be refused; a use the plan forbids can be halted.

That legal weight is the whole reason the underlying data must be exact. A land-use boundary drawn ten metres wrong on a 1:20,000 sheet is a survey error; the same boundary controlling whether a family may build a shop is a legal fact. This is why the profession has spent two decades moving the plan off paper and onto a coordinate-correct GIS base - so that the boundary you argue over is the same boundary in every office.

Planning in India is deliberately layered. At the top sits the Perspective Plan - a twenty-to-twenty-five-year vision with broad policy and no plot-level detail. Below it, the Master / Development Plan allocates land use and density (FAR) across the whole urban area for about twenty years. Below that, a Zonal Plan or development scheme details one zone. At the bottom, a Layout Plan or Local Area Plan fixes the actual plots, roads and the buildable ground.

Each tier must sit inside the one above it: a layout cannot zone land the Master Plan reserved for a park. In GIS terms this is nested polygons with a parent-child relationship - and a good geo-database enforces it, so that a change at one level flags a conflict at another instead of quietly contradicting it.

Two names recur. The Town and Country Planning Organisation (TCPO) is the Government of India's technical arm for urban planning; it issues the model guidelines states adapt. Its URDPFI Guidelines (Urban and Regional Development Plans Formulation and Implementation, 2015) are the working handbook - they define the plan hierarchy above, the standard land-use categories, the population-based norms for amenities, and, crucially for us, the recommended map scales and data structure.

URDPFI is guidance, not statute - each state's Act is the binding law, and local practice varies. But because most cities follow it, it is the closest thing to a common grammar. When a brief says 'as per URDPFI norms', it is pointing at a shared table of standards you can look up rather than guess.

Two national programmes did the heavy lifting. The National Urban Information System (NUIS), launched in 2006 by TCPO, built urban spatial databases for scores of towns at planning scales - 1:10,000 for the city, 1:2,000 for zones, and 1:1,000 for utilities. Then the AMRUT sub-scheme for GIS-based Master Plans (approved under AMRUT, driven by TCPO/MoHUA) set out to produce coordinate-correct GIS base maps and land-use maps at 1:4,000 for hundreds of cities, feeding a national urban geo-portal.

The workflow is a pipeline. A base map is assembled from high-resolution satellite imagery plus ground survey (often DGPS). Features are digitised into a structured geo-database. Surveyors record the existing land use. Planners draft the proposed land use - the plan itself. The draft goes to public objection, is revised, and is finally notified. Every stage is a GIS dataset, which is why an architect who can read a GeoPackage can now read the plan at its source.

The scale a plan is drawn at decides what it can even say. At 1:10,000 you see blocks and major roads; individual plots are a blur. At 1:2,000 plots appear and land use can be assigned parcel by parcel. At 1:1,000 you can carry water mains, sewer lines and poles. NUIS chose exactly these three because they match the three planning questions - city structure, zonal use, utility routing.

The practical trap: never measure or claim precision the scale does not support. A boundary captured at 1:10,000 carries perhaps five-to-ten metres of positional slack; pasting a building footprint against it as if both were survey-accurate invents a certainty that is not there. Read the scale first, then decide what the layer is allowed to prove.

GIS master plans are transformative but not magic. Coverage is uneven: many smaller towns still run on scanned sheets, and even where a GIS plan exists, the notified version may lag the digital draft by years. Existing-land-use surveys age the moment they are done, in cities that change monthly. Informal and mixed uses - a home that is also a workshop and a shop - resist the tidy single-category model. And access varies: some city portals are open, others gate the data behind the local authority.

None of this is a reason to distrust the plan; it is a reason to date-stamp every layer, note its scale and source, and treat the plan as the best available legal snapshot rather than live ground truth.