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27 guides on Raster.
What is a Digital Elevation Model? DEM vs DSM vs DTM
A digital elevation model (DEM) is a raster in which every cell holds a height, on a regular grid with a known cell size, horizontal coordinate system, and vertical datum. The term covers two kinds of model. A digital terrain model (DTM) records the bare ground. A digital surface model (DSM) records the first surface […]
What is Catastrophe Modeling? Cat Models Explained
Catastrophe modeling, or cat modeling, is the practice of estimating the financial losses that a portfolio of buildings and insurance policies could suffer from rare, severe natural events. They are hurricanes, earthquakes, floods, wildfires, and severe convective storms, the thunderstorms that bring hail, tornadoes, and damaging straight-line wind. A cat model is a stochastic model, […]
What is Change Detection in Satellite Imagery?
Change detection is the process of comparing two or more images of the same place, captured at different times, to find where and how the surface has changed. Ashbindu Singh's review Digital change detection techniques using remotely-sensed data (International Journal of Remote Sensing, 1989) gave the definition most papers cite. It defines change detection as […]
