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Mapping with ArcGIS Pro by Ryan Malhoski, Amy Rock

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Vertical coordinate systems

Many devices now have GPS units in them, which means you can take measurements out in the field even easier; however, just like how you have to take a horizontal geographic coordinate system and project it, you must do something similar for vertical measurements. When using a GPS unit, you can get an elevation for a location and this elevation is based on a spheroid model, specifically the WGS 84 reference spheroid. The spheroid model is not related to sea level, and height above sea level is how most elevations are given in the real world. The height above sea level is called the geoid height. To get the geoid height, you must project the elevation. There are many tools that can perform this for you, but it can ...

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