What Is a Shadow Map and How Do You Check Sunlight and Shade for a Place?
A shadow map is an online tool that simulates the shadows cast by buildings, trees, and terrain for any date and time, so you can see where sunlight falls and where shade sits at a specific location. ShadeMap (shademap.app) is one example: it runs in a browser, requires JavaScript to be enabled, and lets you simulate shadows in 3D without installing or buying Google Earth Pro. Use it when you need to check sun exposure for a garden, house, photo shoot, or shadow study — and treat the results as a simulation, not a survey.
What a Shadow Map Actually Shows
A shadow map combines two things:
- Sun position — where the sun is in the sky for a given date, time, and place.
- Shadow direction and extent — how that sun angle projects shadows from real-world features onto the ground.
Because both are tied to time, the same location looks completely different at 9 a.m. and 4 p.m., or in June versus December. The map is not a static picture of shade; it is a time-dependent simulation.
ShadeMap's page describes it as an "online shadow map and sun finder" that can simulate shadows cast by buildings, trees, and terrain in 3D, and that can generate shadow accumulation and shadow accrual maps.
How to Check Sunlight and Shade for a Place
The general workflow for any shadow map tool:
- Open the tool in a browser with JavaScript enabled. ShadeMap explicitly states JavaScript must be enabled to run the app.
- Navigate to your location. Move the map to the house, garden, or site you care about.
- Set the date and time. This is the step that determines everything — sun position and shadow direction both follow from it.
- Read the shadows. Look at which areas fall under simulated shadow from buildings, trees, and terrain, and which stay lit.
- Change the time and repeat. Sweep through the day to see how shade moves across the site.
The expected result is a visual answer to questions like "Is this garden bed in sun at noon in March?" or "Will this wall be shaded at sunset in winter?"
Practical Uses
Garden and house sun exposure
Set the date to the season you care about and step through morning, midday, and afternoon. A spot that is sunny at noon may be shaded most of the day by a neighboring building or tree. Checking several times is more useful than checking one.
Planning sunrise and sunset photos
Because the tool simulates sun position and shading for sunrise and sunset, you can preview how light and shadow will fall on a scene before you go. This helps you pick a viewpoint and a time rather than guessing.
Shadow studies and solar analysis
ShadeMap's page lists preparing a "shadow study, shadow analysis or solar analysis" as a use case. These are structured assessments of how shade behaves over time at a site.
Finding the sunniest or shadiest spots
Shadow accumulation and shadow accrual maps show how shade builds up over a day rather than at a single moment. Use these when you want to compare spots across a full day — for example, to find the most consistently sunlit part of a garden.
Reading the Results Correctly
| What you set | What it changes |
|---|---|
| Location | Which terrain, buildings, and trees are simulated |
| Date | Sun path and shadow length/angle for the season |
| Time | Sun position and shadow direction at that moment |
| Accumulation view | Total shade over a period, not a single instant |
A single-time view answers "where is shade right now (at this time)?" An accumulation view answers "where is shade most of the day?" These are different questions — pick the view that matches what you need to decide.
Common Limits and Gotchas
- JavaScript is required. If the page appears blank or non-functional, check that JavaScript is enabled in your browser.
- Simulation, not measurement. Shadows are simulated from terrain, building, and tree data. Accuracy depends on that data, so treat results as a strong guide rather than a precise on-site measurement.
- Trees and vegetation change. A simulated tree shadow reflects the data the tool has, not the current canopy of a specific tree.
- Time zone and date matter. Always confirm you have set the correct date and time for the location, since sun position depends on both.
If you need a quick, no-install way to understand how sun and shade behave at a place and time, a shadow map like ShadeMap is built for exactly that. If you need surveyed, legally binding shadow measurements, use it as a first pass and verify on site.