1. Real Terrain
Continuous irregular surface
Terrain Visualization Lab
See how 3D terrain turns into contour lines.
Compare the same terrain as a 3D surface and a contour map. Build the mental model for reading topo before going into the field.
Start by scrubbing the elevation slice slider up through the terrain — watch contours appear. Then try changing the interval or resolution. If this tool helps your training, consider supporting the project.
How Terrain Becomes Topo Lines
Real terrain is a continuous surface. To make a topo map, software samples it into a grid of elevation values — a Digital Elevation Model (DEM) — then cuts that grid at evenly spaced elevations. Each cut edge becomes a contour line.
2. DEM — Elevation Grid
Each cell stores one elevation value
3. Elevation Slices
Even horizontal cuts through the grid
4. Contour Map
Cut edges drawn as lines
3D Terrain View
Drag to rotate. The horizontal plane shows the current slice elevation.
2D Contour Map
Contours generated from the same terrain. The highlighted line marks the contour nearest the current slice elevation.
Controls
Use the slice slider first, then adjust DEM resolution and contour interval to compare.
Drag the slider to move the cut up and down. The filled area shows everything below the current slice level.
Teaching Notes
How DEM and Contour Settings Work
Static reference illustrations. These don't respond to your controls — use them to understand what each setting is actually doing.
DEM Resolution Explained
Same terrain, different sampling density. Finer DEMs preserve smaller shape changes.
Contour Interval Explained
Wider intervals mean fewer terrain slices. Fewer slices mean fewer contour lines.
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