🏔 Elevation tab
Colors show height above sea level. Green = low ground, tan/brown = mid elevation, white = peaks. The color scale adapts to the area you're viewing — so "green" in Montana is a different altitude than "green" in Florida.
Contour lines connect points of equal elevation. Closely packed lines = steep slope. Widely spaced = gentle or flat terrain. Every fifth contour (index line) is thicker and labeled.
Why it matters: Elevation tells you where water naturally drains — and where it collects.
💧 Hydro tab
Shows where water goes when it rains. Deep blue areas are valley bottoms and stream channels — water from many uphill directions funnels through these spots. Light gray/white areas are ridges and high ground where rain runs away from you in all directions.
The moving dots simulate water particles following the terrain downhill. Watch them gather in the valleys.
Why it matters: A valley-bottom lot means all the rainwater from surrounding hills eventually passes through your land — even on a clear day, your drainage situation depends on your neighbors uphill.
☀️ Solar tab
Shows the annual average solar resource at your location from the NREL National Solar Radiation Database (NSRDB). The key number is Global Horizontal Irradiance (GHI) — the total sunlight hitting a flat, horizontal surface per day, measured in kilowatt-hours per square meter (kWh/m²/day). Higher is better for solar panels.
US ranges: the Southwest (Arizona, Nevada, New Mexico) leads at 5.5–6.5 kWh/m²/day. The Southeast and Midwest average 4.5–5.5. The Pacific Northwest and New England average 3–4. At the optimal tilt angle for your latitude, you can capture 10–20% more than the flat-plane GHI.
Terreflow adjusts the estimate for your slope and aspect. A south-facing hillside intercepts more sun than flat ground at the same location; a north-facing slope gets less. This is an estimate — a full solar assessment should include on-site shading analysis.
⚠️ Hazards tab
Flood
Official FEMA flood zones drawn from detailed engineering studies. Zone AE / A: high risk — 1% chance of flooding every year (the "100-year flood"). Federally-backed mortgages almost always require flood insurance here. Zone X shaded: moderate risk (0.2% per year). Zone X unshaded: minimal risk, outside the 500-year floodplain. Zone V / VE: coastal areas with wave action — the highest risk category.
The flood map only covers areas that have been studied. No color ≠ no risk — it might just mean no study was done yet.
Seismic
Ground shaking hazard from the USGS National Seismic Hazard Model. Warmer colors = stronger expected shaking. The number shown (Ss) is short-period ground acceleration as a fraction of gravity — 1.0g is very strong, 0.1g is minor. The Pacific coast, Pacific Northwest, and Alaska are highest risk. The central US (New Madrid fault zone) has moderate risk that surprises many people.
Fault lines
Mapped fault traces from the USGS Quaternary Fault Database — places in Earth's crust that have moved in the past 1.6 million years and could move again. Being close to a fault means higher chance of strong shaking AND possible surface rupture during a major earthquake. Most building codes prevent construction directly on active fault traces. The distance to the nearest fault is shown when you click a location.
Fire
Wildfire Hazard Potential from the USFS — a structural risk score based on fuel load, historical fire weather patterns, and topography. Green = low hazard, red = extreme. This shows long-term structural risk, not current fire activity. The West Coast, Pacific Northwest, and parts of the Intermountain West show the highest ratings. Click any location to see the specific hazard class.
🛰 Satellite tab
Real aerial/satellite imagery draped over the 3D terrain — use this to visually confirm you're looking at the right location and to see land cover, vegetation, and built features.
🌱 Soil tab
Soil data from the ISRIC SoilGrids global database. The map shows clay content (0–5 cm depth): dark = high clay, light = sandy. Clay-rich soils drain slowly, shrink and crack when dry, and can cause foundation movement. Sandy soils drain fast but hold fewer nutrients.
Click any location to see three properties: Clay % (drainage, plasticity, foundation risk), pH (acidity — affects what grows and how metals leach), and Organic Carbon (fertility and water-holding capacity).
These are modelled values at 250m resolution, best used for regional comparisons. For a construction project, get a site-specific geotechnical survey.
📊 Vertical Profile chart
A cross-section of the ground from west to east (X direction) or south to north (Y direction). The red star marks where you clicked. Use this to see whether you're sitting in a valley, on a ridge, or partway up a hillside — and how steep the slope is over a distance of several kilometers.
📝 Interpretation panel
Plain-language summary of what all the numbers mean for your specific location. It compares your site to the surrounding neighborhood, explains drainage patterns, notes solar exposure from slope direction, and flags flood and hazard context. Updated every time you click the map or enter an address.
🎛 Controls
Address box: accepts anything — a street address, a place name, a lon,lat pair (e.g. -95.63, 29.75), or an x,y Mercator coordinate. Just paste and hit Convert.
ft / m: switch between feet and meters for elevation and contour labels. Contours on/off: toggle the contour lines. Vertical exaggeration slider (left edge of map): drag up to stretch the terrain vertically — useful for flat areas where relief is hard to see. Compass (top-right of map): click it to reset north-up orientation.