An Introduction to Geodetic Datums

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  Publicado el: 2014-07-01
  Tiempo de estudio aproximado: .25 - .50 h
  Incluye sonido: yes

  Áreas temáticas

  Geospatial
  

  Descripción:

  This series of short videos, produced in collaboration between NOAA’s National Geodetic Survey and The COMET Program, provides an introduction to geodetic datums for anyone who uses mapping products or other geo-spatial tools.

  
  1. What are Geodetic Datums? (4:36)
  
  In this video we explain the basic concepts behind geodetic datums, where they are used, and why it is important to know about and use the correct datums.
  
  2. How Were Geodetic Datums Established? (3:12)
  
  In this video, we explore the history of geodetic datums in the United States, and how they were established at a national level to assure consistency across mapping applications.
  
  3. What Is the Status of Today's Geodetic Datums? (4:49)
  
  Here we examine the use of the current primary geodetic datums used in the US, NAD 83 and NAVD 88, the challenges in maintaining these datums, and the inconsistencies that arise when they are used together with the latest satellite-based mapping technologies.
  
  4. What's Next for Geodetic Datums? (4:41)
  
  Finally, we look at current plans for developing more accurate horizontal and vertical datums, (referred to respectively as geometric and geopotential datums), the expected benefits and impacts, and the importance of preparing now to adopt these new datums.
  
  
  
  This resource is hosted on COMET's YouTube Channel.
  

  Objetivos:

  
  
  1. What are Geodetic Datums?
     
     
     
     1. Explain the basic concept of geodetic datums
        
        
     
     
     2. Describe the potential impacts of using the incorrect datum or attempting to combine data sets with different datums
     
     
     3. Understand that location information based on a newer GPS-based reference system must be transformed before use with current NAD 83 and NAVD 88 positions
     
     
     
     
     
     
  
  
  2. How Were Geodetic Datums Established?
     
     
     
     1. Describe how datums were created
     
     
     2. Identify NAD 83 as the current official horizontal datums for the United States
     
     
     3. Identify NAVD 88 as the current official vertical datum for the United States
     
     
     
     
     
  
  
  
  
  3. What Is the Status of Today's Geodetic Datums?
     
     
     
     1. Describe weaknesses of current geodetic datums including accuracy issues, cost and physical limitations
     
     
     
     
     
     
  
  
  4. What's Next for Geodetic Datums?
     
     
     
     1. Explain that new datum approaches are based on GPS/Global Navigation Satellite Systems.
     
     
     2. Understand that new datums will impact different areas of surveying work
        
        
     
     
     3. Recognize the importance of updating legal references to old datum
        
        
     
     
     4. Identify the NGS website as a resource to help with change
     
     
     
     
  
  
  
  

  Palabras clave

  geodetic datums, geodesy, mapping, GIS, NAD 83, NAVD 88, NGVD 29, leveling, surveying, surveyor, floodplain mapping, GPS, GNSS, datums, geomatics, charting, topography, bathymetry, geospatial