Topographic profiles and elevation plans online
With Geostru MAPS you can create digital terrain models, elevation profiles and contour plans, directly from online maps with just a couple of clicks.
After assigning points through Point command, in Calculation menu you can find point’s elevation, trace the topographic section (altimetry profile), numerically edit latitude and longitude coordinates and locate the contour plan “points must be at the extremes of the BOX”.
The work files can be saved localy on your computer and processed data can be exported in various vectorial formats including *.dxf, *.gtm and also *.sec format which is compatible whit Geostru software.
Mathematical model for calculating the altitude at sea level
The values of the altitude at sea level are calculated regarding the geoid.
The geoid is a surface perpendicular at every point to the vertical direction, that is to the force of gravity‘s direction. It is the surface that best describes the average ocean surface (without considering the influence of tides, currents and meteorological effects) and therefore the average surface of the Earth. This, in fact, can be defined as the equipotential surface (that is, where the gravitational potential has equal value) whit the minimum deviation from the average sea level.
Reference graphic model
The below image is a graphic representation of the reference mathematical model for the calculation of the elevation.