Bill Rankin, 2006
Tax assessments are a tricky data source, since they do not measure market value — indeed, there are even tax-assessed "values" on public buildings and parks. (Here Central Park is "valued" at $1.9 billion.) But they do give a rough sense of relative values within the city: the pocket of wealth up near the cloisters, and the relative sparseness of the lower east side.
Note: even though this map shows building footprints, the land value shown for each building is per square foot of lot size.