Solar Row Spacing API

Solar-array row-spacing and shading geometry as an API, computed locally and deterministically — the shadow-length, inter-row-spacing and ground-coverage numbers a PV designer or installer lays a ground-mount or flat-roof array out with. The shadow-length endpoint gives the shadow an object casts = its height ÷ tan(sun elevation), longer the lower the sun (which is why layouts are designed for the worst-case winter-solstice low sun), stretched by 1/cos(azimuth difference) when the sun is off-axis. The row-spacing endpoint gives the minimum row pitch (front edge to front edge) to stop a row shading the one behind = the module's horizontal base (length × cos tilt) + the shadow its back edge casts (module height ÷ tan of the minimum sun elevation) — a 1.7 m module at 30° tilt clearing a 20° winter sun needs about a 3.8 m pitch — and returns the resulting ground coverage ratio. The ground-coverage endpoint gives that GCR = module length ÷ row pitch, the packing density: fixed-tilt fields typically run 0.4–0.5, higher packs more kW per acre but loses winter yield to mutual shading, lower wastes land. Everything is computed locally and deterministically, so it is instant and private. Ideal for solar-design and layout tools, EPC and site-assessment apps, and renewable-energy calculators. Pure local computation — no key, no third-party service, instant. Geometric model — use the real worst-hour sun altitude. 3 compute endpoints. For solar position/altitude use a solar-position API; for irradiance a solar API; for off-grid sizing an off-grid API.