Sun Trajectory Calculation Map

GIS, Simulation

Free
No Download/Install required
No registration

It gives you on an interactive map of the sun trajectory everywhere on earth at any given time and any season.

Extremely useful to see the differences between location and seasons, or why and when on Groenland you have no sun or if the sun can rise more north than just east!

SunCalc is a web-based solar tracking application that calculates the sun’s position, sunlight phases, and shadow dynamics for any geographic location and date. It utilizes astronomical algorithms to provide precise data on sunrise, sunset, and twilight times, alongside the sun’s azimuth and altitude relative to the horizon. The interactive map interface allows users to simulate solar paths throughout the year, facilitating the visualization of seasonal variations in light duration and the calculation of shadow lengths for objects of specific heights.

Professionals in engineering and architecture apply these data sets to conduct shadow impact assessments and optimize building orientations for energy efficiency and natural lighting. In the renewable energy sector, the tool is used to determine the optimal placement and tilt of photovoltaic arrays to maximize solar irradiance capture.

Disciplines: Architecture, Solar energy, Photography, Urban planning, Landscape design.

Free alternative to Sun Surveyor, Ladybug Tools.

SunCalc compared with Sun Surveyor and Ladybug Tools
SunCalc	Sun Surveyor	Ladybug Tools
Platform and use: A web application on an interactive map. The map uses Google Maps API v3. Sun trajectory is shown for any location and day, with a time slider. No sign-up is mentioned.	Platform and use: A mobile app for iOS and Android with an augmented-reality Live View, an interactive map and Street View panoramas. It is designed for use on site.	Platform and use: A set of plugins (Ladybug, Honeybee, Butterfly and Dragonfly) that run inside Rhino and Grasshopper on Windows and Mac, depending on the version. Python code connects the 3D model to Radiance, EnergyPlus and OpenStudio, and OpenFOAM through Butterfly. It needs a CAD host and some visual scripting skill.
Outputs: Sun positions at sunrise, at a chosen time and at sunset, the daily trajectory, its yearly variation and sunlight phases from night to solar noon and dusk. Shadow length for an object of a given height can be estimated.	Outputs: Sun and moon overlays on a map, distance and elevation calculations, shadow visualisation, an annual sun ephemeris, solstice and equinox paths, horizon obstruction and golden and blue hour times. Moon phases and Milky Way core visibility are also given.	Outputs: Sun path diagrams, wind roses and psychrometric charts from hourly climate data. Geometry studies include solar radiation, shadows and view analysis, and the linked engines give daylighting and energy simulation results.
Method and validity: Calculations rely on the Astronomy Answers formulae. The page does not give an accuracy figure, and the tool does not model a building or terrain. Results suit orientation and shading studies at early design stage.	Method and validity: The vendor page does not describe the algorithm or an accuracy figure.	Method and validity: The tools hand the calculation to established engines such as Radiance and EnergyPlus. Results therefore depend on the model geometry, the simulation settings and the climate data chosen. No accuracy figure for the sun path component was found.
Status and cost: Free to use. The page states it has not been updated in 15 years and that a new version is in development.	Status and cost: The vendor page lists no price. Check the App Store or Google Play listing for the current price.	Status and cost: Free and open source, licensed under AGPL-3.0 or later, with code on GitHub. Version 1.8.0 is the latest release listed on the Food4Rhino page, which gives no release date.
When to choose it: Choose it for a fast check of sun path, season and shadow from a desk, for architecture, PV siting or photography.	When to choose it: Choose it when you stand at the actual site and need to see the sun path against the real horizon.	When to choose it: Choose it for climate-based daylight, radiation and energy studies on a 3D building model in Grasshopper. For a quick sun position check without a model it is heavier than a web map.

Topics covered: Sun trajectory, solar tracking, geographic location, astronomical algorithms, sunrise, sunset, twilight, azimuth, altitude, interactive map, seasonal variations, shadow dynamics, shadow impact assessments, building orientations, energy efficiency, natural lighting, photovoltaic arrays, solar irradiance capture, ISO 50001, ISO 14001, ASHRAE 901, IEC 61215, and ASTM E2848..