Tools/street_mesh.py builds the corridor in the project frame from the measured
profile: carriageway -10.5..+10.5 m, kerbs 0.15 m (0.13 m as built), sidewalks
4.0 m south and 5.3 m north, all elevations sampled from the DEM. Kerbs flush at
the three signalised crossings. Crown at mid-block reproduces the cross-sections
to the centimetre.
Tools/terrain_from_dem.py builds a 191x106 grid at 2 m over the block, Z being
NAVD88 minus the origin ground. Building footprints from the OSM extract are cut
out so rooftops never become terrain (72 footprints, 6310 cells). Spot checks
reproduce the measured profile: origin 0.00, Orange Dr +3.39, south gutter
+0.93, crown +1.38, north sidewalk +1.43.
Blosm projects with a sphere, not an ellipsoid, so its frame was ~0.4% oversized
and rotated by meridian convergence: about 2 m at the theatre. The blockout now
fits a six-parameter affine into EPSG:26911 on five control points (0.0 cm
residual) and transforms root objects only, since children inherit and double
transforming them read as a 2 m placement error.
Gutters sit at -10 m south and +10..12 m north, a ~2% crown between them, and
the envelope runs 0.6-1.0 m per section. Gutter spacing independently confirms
the 20.9 m carriageway measured from the crossing. The sharpest breaks are
0.09-0.12 m/m, so 3DEP does not resolve a kerb upstand: kerb height stays a
recorded assumption rather than a derived value.
zwitschi