In a hypothetical "perfect market," this map would be a consistent yellow-green. Every lot would be built up precisely in accord with its land value. Lots which were underdeveloped would be torn down and built up again with higher densities. Overdeveloped sites would lower the price of nearby lots, again establishing equillibrium. But government distorts the market (often in very good ways), by building low-density public buildings and monuments in central areas (e.g., the Public Library or Lincoln Center), or building public housing that the market would not otherwise provide (see the lower east side). Zoning also restricts development for the sake of light, air, and congestion.

Notice the difference between Midtown and Wall St.: Downtown looks very close to a "perfect market," while Midtown seems restrained by zoning. Notice also underdevelopment along Madison Ave. and Broadway, and the (thankfully) "irrational" presence of churches throughout the city.

Note: See also methodological notes about tax-assessment data on the Land Value map.