Photogrammetry - using photography in surveying and mapping to measure between objects.
Orthomosaic - A 2D geolocated photographic map that’s has a uniform scale to allow 2D measurement of a mapped/surveyed area.
Point Cloud - A set of 3D points that reconstruct a model. Used in 3D modelling software such as Revit, AutoCAD Civil 3D, Sketch-up and others.
DTM - A Digital Terrain Model is 2.5D model of a mapped area without objects such as trees, buildings and other man made object.
DSM - A Digital Surface Model is a 2.5D model of a mapped area.
Absolute Accuracy - The accuracy of a map or model in regards to an objects or points compared actual position on the face of the earth.
Relative Accuracy - The accuracy of objects or points measured within a map or model in regards to their actual measured distance with conventional measuring methods.