Street line

The street line is the boundary between a zoning lot and the street — the front lot line. It is the datum from which much of the bulk machinery measures: front yards run along it, street walls are held at or near it, base heights rise from it, and sky exposure planes begin their slope above it. Where a lot fronts more than one street, it has more than one street line, which is how corner and through lots acquire their distinctive obligations.

The street line follows the legal street shown on the City Map, which does not always match the built curb — mapped widenings and paper streets can place the legal line where the sidewalk disagrees. Surveys and the tax map settle its location; massing analysis inherits whatever the answer is.