Global Land Cover Characteristics Data Base (GLCC World)

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This clutter model provides global coverage at a 30 arc second resolution using 17 clutter categories. Details are available at https://lta.cr.usgs.gov/GLCC. The primary use of this database will be for link feasibility studies which require an estimate of the land cover elevations to establish antenna heights.

The database consists of a single file - gigbp2_0ll.img (933,120,000 bytes). This file can be down loaded in a zipped format from http://edcftp.cr.usgs.gov/project/glcc/globe/latlon/gigbp2_0ll.img.gz The size of the zipped file gigbp2_0ll.img.gz is 27, 460,036 bytes

The Pathloss program is preconfigured to use this file. Once the file has been down loaded and unzipped, verify the file size. Carry out the following steps in the clutter tab in the GIS configuration:

  • Select the GLCC clutter model
  • Click the Setup button and identify the directory containing the file gigbp2_0ll.img
  • Click the Definition button and edit the base clutter heights for your area.

National Land Cover Data (USA including Alaska)

The data is available from the National Map Seamless Server http://seamless.usgs.gov/website/seamless/view-er.htm . Set the Display - Download selection to Download. Two data sets are available - NLCD1992 and NSCD2001.

Both data sets use the Albers equal area conic projection with different parameters for the contiguous United States and Alaska. The data must be in the BIL format. The default data format is GeoTIFF which may be useful as backdrop imagery; however this cannot be used for clutter on terrain profiles. On the Request Summary Page it is important to click Modify Data Request and set the data format to BIL.

The pathloss program is preconfigured to use either the NLCD1992 or NLCD2001 data in the contiguous United States or Alaska. Carry out the following steps in the clutter tab in the GIS configuration:

  • Select the NLCD-1992/2001 clutter model for CONUS or Alaska
  • Click the Setup button and identify the directory containing the clutter data files. Alternately, individual directories for each clutter file can be used.
  • Click the File index button and then select the Files - Import Index - bil, hdr, blw files menu item. Note that the file open dialog box contains an option to use a single main directory or individual file directories. Select the file and the index will be created.
  • Click the Definition button and edit the base clutter heights for your area
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