Orthophoto Engineering Concepts

An orthophoto is a raster image that has been geometrically corrected so measurements and positions can be treated in map space. It differs from a normal photo because perspective distortion is corrected relative to terrain, camera pose, and processing assumptions.

A COG is a GeoTIFF arranged for efficient HTTP range requests. In a web viewer, this allows the browser to request only the tiles and resolution levels needed for the current view rather than downloading the entire raster at once.

Pixel size controls the ground distance represented by one raster pixel. Smaller pixel size can provide more detail, but accuracy also depends on source quality, control, camera calibration, processing settings, and projection correctness.

A coordinate reference system defines how raster coordinates map to the earth. Measurements, overlays, and exported findings are only reliable when projection metadata is present and consistent with the mission region.

Hillshade creates a relief-like visualization from elevation data. Ground Bands classify terrain ranges to make ground-level variation easier to read. Raised Features emphasize objects and surfaces above terrain, often by using DSM-DTM differences.