DSM & DTM elevation models

Elevation models describe the height of your site at every point. MapperTool can produce two kinds, and the difference is simple:

• DSM (Digital Surface Model) — the height of everything the camera saw: ground, buildings, trees, vehicles, stockpiles. It is the "top surface" of the scene.
• DTM (Digital Terrain Model) — the height of the bare ground, with objects above it filtered out. It is what the site would look like with the buildings and vegetation removed.

Which one you need depends on the question you are asking. Measuring the height of a building or a stockpile? The DSM has it. Planning drainage, grading or earthworks? The DTM shows the terrain itself. Comparing the two is a common way to estimate the height of objects on the site.

Both models open as map layers in the viewer, where you can also take height measurements with the measurement tools, and both can be downloaded for use in GIS or CAD software.

Work in progress

This guide is being written. The essentials above are accurate today; the detailed walkthrough lands here soon.