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Digital Elevation Model (DEM) Data Sources That You Can Get Easily

Digital Elevation Model (DEM) Data Sources That You Can Get Easily. Quadrilateral Data Structure. Grid cell resolution constant N-S but progressively finer E-W resolution from equator to pole. Geodetic latitude and longitude on WGS 84 ellipsoid (NAD 83). ETOPO2 Global DEM

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Digital Elevation Model (DEM) Data Sources That You Can Get Easily

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  1. Digital Elevation Model (DEM) Data SourcesThat You Can Get Easily

  2. Quadrilateral Data Structure Grid cell resolution constant N-S but progressively finer E-W resolution from equator to pole Geodetic latitude and longitude on WGS 84 ellipsoid (NAD 83)

  3. ETOPO2 Global DEM from National Geophysical Data Center

  4. Technical Specifications (0,0) Row Major Order (10799,0) Worldwide Land And Sea Elevation Data In Meters (3.7x3.7km cells at equator) 2-byte signed integer data 5400 rows by 10800 columns 116,640,000 byte dataset (0,5399) (10799,5399)

  5. CleanTOPO2

  6. Global Land One-km Base Elevation (GLOBE) DEM data from NGDC • 30” x 30” grid cells for the earth • Metric data for land areas, NoData • value (-500) given to sea areas

  7. Spatial Resolution 0.93 x 0.93 km Cells at equator

  8. Globe 30” x 30” grid cell data structure and tiling, format, and dataset size

  9. USGS GTOPO30 Global Land DEM • Integer Metric data for land areas, • NoData value (-9999) given to • sea areas. • 30” x 30” grid cells for the earth. • Single GRID dataset on ESRI • Data & Maps (21,600 rows x • 43,200 cols. [1.866GB file])

  10. USGS Version Has 33 Tiles

  11. Shuttle Radar Topography Mission (SRTM) 3 arc-second (90m) data from USGS EROS

  12. Each grid is divided into 1 degree tiles (1200 x 1200) for land areas Grid 2

  13. Data are First • Reflective Returns • Data Completeness • Problems

  14. Voids are Filled in ESRI Maps and Data 90m SRTM Dataset Data are Compressed From 34GB to 4.33GB

  15. Shuttle Radar Topography Mission (SRTM) 1 arc-second (30m) data from USGS EROS

  16. Each grid is divided into 1 degree tiles (1200 x 1200) for land areas Grid 4

  17. SRTM Data are also available from The National Map Seamless Server

  18. National Elevation Dataset (NED) from The National Map Seamless Server

  19. National Elevation Dataset (NED) Data Structure • One-second grid cells for all • U.S. states except Alaska • 31m N-S resolution • 28m to 20m E-W resolution • NAD 83 lat./long. cell centers • from 25° to 50° N • Full dataset is about 60GB

  20. Two-second Grid For Alaska • NAD 83 lat./long. cell centers • 62m N-S resolution • 38m to 21m E-W resolution • from 52° to 70° N

  21. National Elevation Dataset (NED) Data Format and Tiling Scheme

  22. National Elevation Dataset (NED) 1/3rd (10m) and 1/9th (3.3m) Arc-second Grids for Certain Areas from The National Map Seamless Server

  23. You can buy the Data for each state In ArcGIS GRID format

  24. Light Detection And Ranging (LIDAR) Data Uses a laser and sensor to transmit and receive pulses from reflected surfaces

  25. Post processing of the return data produces a highly accurate DEM, typically with 1 meter spatial resolution. LIDAR DEMs available only for small local areas

  26. USGS National Land Cover Data (NLCD) 2001 1”x1” Grid

  27. From The National Map Seamless Server

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