Coastal elevation file 2009

Height model of the coast in the form of a grid with a resolution of 5 meters where the height value is included in meters. Parts of the sandy coast of the Netherlands are recorded in height every year for the production of beach profiles for monitoring the coastline. A digital height model (DHM) is a file where the height is represented according to a regular, rectangular grid. Each cell of the grid (also called a grid cell) is given a height value. This height value is calculated from the surrounding laser points of the filtered base file. The technique used for this is a so-called weighted mean interpolation. More information and an explanation about the interpolation can be found in the AHN grids manual, which can be found at www.ahn.nl. If there are no laser points near a grid cell, the cell remains empty (the cell gets a nodata value). It is important to know that the value of a 5x5 meter grid cell is calculated from several laser points (the number depends on the point density of the base file). As a result, the influence of the measurement noise and outliers decreases and a slight degree of flattening occurs. Laser altimetry height data was collected according to RWS regulations. For detailed information see attached quality document