Скачать презентацию Digital Elevation Model DEM Data Sources That You Скачать презентацию Digital Elevation Model DEM Data Sources That You

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

ETOPO 2 Global DEM from National Geophysical Data Center ETOPO 2 Global DEM from National Geophysical Data Center

Technical Specifications (0, 0) Row Major Order (10799, 0) 2 -byte signed integer data Technical Specifications (0, 0) Row Major Order (10799, 0) 2 -byte signed integer data Worldwide Land And 5400 rows by Data Sea Elevation 10800 columns In Meters 116, 640, 000 byte dataset (3. 7 x 3. 7 km cells at equator) (0, 5399) (10799, 5399)

Clean. TOPO 2 Clean. TOPO 2

Global Land One-km Base Elevation (GLOBE) DEM data from NGDC • 30” x 30” Global Land One-km Base Elevation (GLOBE) DEM data from NGDC • 30” x 30” grid cells for the earth • Metric data for land areas, No. Data value (-500) given to sea areas

Spatial Resolution 0. 93 x 0. 93 km Cells at equator Spatial Resolution 0. 93 x 0. 93 km Cells at equator

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

USGS GTOPO 30 Global Land DEM • Integer Metric data for land areas, No. USGS GTOPO 30 Global Land DEM • Integer Metric data for land areas, No. Data 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. 866 GB file])

USGS Version Has 33 Tiles USGS Version Has 33 Tiles

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

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

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

Voids are Data are Filled in ESRI Compressed Maps 34 GB to and Data Voids are Data are Filled in ESRI Compressed Maps 34 GB to and Data From 90 m SRTM Dataset 4. 33 GB

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

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

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

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

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

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

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

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

You can buy the Data for each state In Arc. GIS GRID format You can buy the Data for each state In Arc. GIS GRID format

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

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

USGS National Land Cover Data (NLCD) 2001 1”x 1” Grid USGS National Land Cover Data (NLCD) 2001 1”x 1” Grid

From The National Map Seamless Server From The National Map Seamless Server