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1. Home
2. Education
3. Geodesy
4. What is Geodesy?

**What is Geodesy?**  The earth's crust is made of up separate plates  that ride atop a sea of magma. These plates are constantly shifting and  interacting. The phenomena that affect the size and shape of the  Earth's continents and ocean basins are subtle and occur over hundreds  of thousands of years. (Image source: GIS-based plate boundaries,  ETOPO2 global elevation data). The earth's crust is made of up separate plates that ride atop sea of magma that are constantly shifting and interacting  The earth's crust is made of up separate plates that ride atop sea of magma that are constantly shifting and interacting  The earth's crust is made of up separate plates that ride atop sea of magma that are constantly shifting and interacting
  Geodesy **Lessons** Welcome What is Geodesy? The History of Geodesy The Geoid What is a Datum? The Horizontal Datum The Vertical Datum Gravity The National Spatial Reference System The Global Positioning System CORS and GIS References
  More **Information** Roadmap to Resources Subject Review Is the Earth round? (Ocean Facts)  Geodesy Education Heard of geodesy? These videos from NOAA's National Geodetic Survey offer a deep dive into the science of knowing where you – and everything else is in the world!
  The National Science Teaching Association (NSTA) includes this resource in its database. NSTA provides educators and students access to Web-based, educationally appropriate science content that has been formally evaluated by master teachers.
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  **Last updated:** 02/26/21 **Author:** NOAA How to cite this article Contact Us


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