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Clear, practical guides on terrain data and survey engineering: DEM, DSM and DTM, point clouds, orthophotos, cut/fill, stockpile volume and cross-section cubature.
A Digital Elevation Model (DEM) is a raster grid of ground elevations. Learn what a DEM is, how it is made and used, and how it differs from a DSM and DTM.
ReadDEM, DSM and DTM are often confused. Learn the difference between a Digital Elevation Model, Digital Surface Model and Digital Terrain Model, and when to use each.
ReadAn orthophoto is a geometrically corrected aerial image with uniform scale, so you can measure on it. Learn what an orthophoto and orthomosaic are and how they are used.
ReadA point cloud is a dense set of 3D points from LiDAR or photogrammetry. Learn what point clouds are, the LAS and LAZ formats, and how they become usable surfaces.
ReadCut and fill is the earth removed or added to reach a target surface. Learn how cut/fill volume is calculated, why the reference surface matters, and common pitfalls.
ReadStockpile volume is the material above the pile's base. Learn how stockpile volume and tonnage are calculated, why the reference base matters, and how surveys make it fast.
ReadCross-section cubature computes earthwork volume from sections along an alignment. Learn how stationing, end-area volumes and section drawings work in practice.
ReadGeoTIFF is a TIFF image with embedded georeferencing, used for DEMs and orthophotos. Learn what makes it 'geo', why it is the standard, and how to work with large ones.
ReadContour lines connect points of equal elevation. Learn how to read contours, what the interval and index lines mean, and how they are generated from a DEM.
ReadSlope measures steepness; aspect measures the direction a slope faces. Learn how both are derived from a DEM and why they matter for siting, drainage and planning.
ReadHillshade, or shaded relief, simulates sunlight on terrain to make its shape pop. Learn how sun azimuth and altitude create the effect and why it aids interpretation.
ReadA coordinate reference system (CRS) defines how coordinates map to the earth. Learn geographic vs projected systems, datums, and why matching the CRS matters.
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