Difference between revisions of "The National Map"

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(Created page with "'''To go directly to the NED download page, go here: http://seamless.usgs.gov/website/seamless/viewer.htm''' The National Elevation Dataset (NED) is a new raster product assemb...")
 
(Using the Gridfloat data in Pathloss 5)
 
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'''To go directly to the NED download page, go here: http://seamless.usgs.gov/website/seamless/viewer.htm'''
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'''Important Note regarding the National Map Viewer'''
  
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Because of ongoing changes to the National Map Viewer file formats we recommend using the Multi Resolution Land Characteristics Consortium [[MRLC]] page to download elevation and clutter data in the BIL format. You can also use the prepackaged grid float format described below.
  
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The National map view page can be found at http://viewer.nationalmap.gov/viewer/ (Not recommended)
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==Information==
 
The National Elevation Dataset (NED) is a new raster product assembled by the U.S. Geological Survey. NED is designed to provide National elevation data in a seamless form with a consistent datum, elevation unit, and projection. Data corrections were made in the NED assembly process to minimize artifacts, perform edge matching, and fill sliver areas of missing data. NED has a resolution of one arc-second (approximately 30 meters) for the conterminous United States, Hawaii, and Puerto Rico and a resolution of two arc-seconds for Alaska. More info can be found at http://gisdata.usgs.net/NED/.
 
The National Elevation Dataset (NED) is a new raster product assembled by the U.S. Geological Survey. NED is designed to provide National elevation data in a seamless form with a consistent datum, elevation unit, and projection. Data corrections were made in the NED assembly process to minimize artifacts, perform edge matching, and fill sliver areas of missing data. NED has a resolution of one arc-second (approximately 30 meters) for the conterminous United States, Hawaii, and Puerto Rico and a resolution of two arc-seconds for Alaska. More info can be found at http://gisdata.usgs.net/NED/.
  
SRTM 30m and SRTM 90m data is also available from the the USGS Seamless Distribution site. Information on the SRTM data can be found at http://srtm.usgs.gov/ .
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==Prepackaged Gridfloat 1" and 1/3" data download==
== How to download ==
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The data can be downloaded at http://viewer.nationalmap.gov/viewer/.
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There is online help available by clicking on the '''Tutorial''' link in the header of the page.
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* Select the '''Download''' tab on the right hand side of the display.
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* Check the boxes for '''NED, 1/3 NED''' or '''1/9 NED'''.
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[[File:sdds_select.JPG]]
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* Using the Zoom tool, you can zoom into the area you are interested in.
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* Define the area by either clicking the '''Define Download Area by Coordinates''' tool under '''Download''' tool group.
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[[File:sdds_download.JPG]]
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http://cumulus.cr.usgs.gov/webappcontent/neddownloadtool/NEDDownloadTool.html
  
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Enter the coordinates for the area to be downloaded or select a state and region. ''Be sure that the longitudes are negative for the west.''
  
* If using the '''Define Download Area by Coordinates''', a dialog will appear that is used to define an area for download. (The example shown is for a 1X1 degree block)
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Be sure to click the download links for the "Pre-packaged Float format" at the desired resolution.
  
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Extract all the files in to a common folder.
  
[[File:sdds_define.JPG]]
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==Using the Gridfloat data in Pathloss 5==
  
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Click Configure -> Setup GIS Configuration and configure the primary DEM
  
* Once the area is defined you will be taken to the download page. You will need to click "Modify Data Request" and change the format to the '''BIL_16INT''' format. Click '''Save Changes & Return to Summary'''.
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[[File:Grdflt-1.JPG|600px]]
  
  
* Click '''Download'''. You will be prompted to save the file once it is ready for download
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Select the top level folder that contains all the DEM.
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Close the index and click OK. (Save the GIS file.)
  
== How to use the seamless NED data with the Pathloss program. ==
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==Using the seamless NED data with Pathloss 4==
 
Decompress the dataset to its own directory. The dataset is comprised of 16 files…
 
Decompress the dataset to its own directory. The dataset is comprised of 16 files…
  

Latest revision as of 15:25, 21 December 2012

Important Note regarding the National Map Viewer

Because of ongoing changes to the National Map Viewer file formats we recommend using the Multi Resolution Land Characteristics Consortium MRLC page to download elevation and clutter data in the BIL format. You can also use the prepackaged grid float format described below.

The National map view page can be found at http://viewer.nationalmap.gov/viewer/ (Not recommended)

Contents

Information

The National Elevation Dataset (NED) is a new raster product assembled by the U.S. Geological Survey. NED is designed to provide National elevation data in a seamless form with a consistent datum, elevation unit, and projection. Data corrections were made in the NED assembly process to minimize artifacts, perform edge matching, and fill sliver areas of missing data. NED has a resolution of one arc-second (approximately 30 meters) for the conterminous United States, Hawaii, and Puerto Rico and a resolution of two arc-seconds for Alaska. More info can be found at http://gisdata.usgs.net/NED/.

Prepackaged Gridfloat 1" and 1/3" data download

http://cumulus.cr.usgs.gov/webappcontent/neddownloadtool/NEDDownloadTool.html

Enter the coordinates for the area to be downloaded or select a state and region. Be sure that the longitudes are negative for the west.

Be sure to click the download links for the "Pre-packaged Float format" at the desired resolution.

Extract all the files in to a common folder.

Using the Gridfloat data in Pathloss 5

Click Configure -> Setup GIS Configuration and configure the primary DEM

Grdflt-1.JPG


Select the top level folder that contains all the DEM. Close the index and click OK. (Save the GIS file.)

Using the seamless NED data with Pathloss 4

Decompress the dataset to its own directory. The dataset is comprised of 16 files…

*.aux          *.hdr       METADATA.dbf  Metadata.xml
*.bil          *.prj       METADATA.prj  NED DataDictionary.pdf
*.bil.aux.xml  *.stx       METADATA.shp  NED_Release_Notes_June10.pdf
*.blw          meta1.html  METADATA.shx  output_parameters.txt

In Version 4.0 make sure to use NED CONUS for data in Alaska. Do not use NED Alaska.

The NED (CONUS) data uses the NAD83. NAD27 Coordinates are transformed automatically.

The SRTM data uses the WGS84. NAD83 and NAD27 Coordinates are transformed automatically.

  • In the Pathloss program click ConfigureTerrain Database and depending on the dataset select either NED CONUSor NED Alaska from the drop down list.
  • Click Setup Primary (or Setup Secondary depending on your selection).
  • Click the file button and browse to find and load the file with the BIL extension. The program is now setup to use the selected BIL file.