Provided by: splat_1.4.0-3_amd64 bug

NAME

       splat An RF Signal Propagation, Loss, And Terrain analysis tool

SYNOPSIS

       splat  [-t   transmitter_site.qth]  [-r  receiver_site.qth]  [-c rx antenna height for LOS
       coverage analysis (feet/meters) (float)] [-L rx antenna height for ITM  coverage  analysis
       (feet/meters)   (float)]   [-p   terrain_profile.ext]   [-e   elevation_profile.ext]   [-h
       height_profile.ext]   [-H   normalized_height_profile.ext]   [-l   ITM_profile.ext]    [-o
       topographic_map_filename.ppm]       [-b       cartographic_boundary_filename.dat]      [-s
       site/city_database.dat] [-d sdf_directory_path] [-m earth radius multiplier  (float)]  [-f
       frequency  (MHz)  for  Fresnel  zone  calculations  (float)]  [-R  maximum coverage radius
       (miles/kilometers) (float)] [-dB threshold beyond which contours will  not  be  displayed]
       [-gc  ground  clutter height (feet/meters) (float)] [-fz Fresnel zone clearance percentage
       (default = 60)] [-ano alphanumeric output file name] [-ani alphanumeric input  file  name]
       [-udt  user_defined_terrain_file.dat]  [-n]  [-N]  [-nf] [-sc] [-dbm] [-ngs] [-geo] [-kml]
       [-gpsav] [-metric] [-olditm]

DESCRIPTION

       SPLAT! is a powerful terrestrial RF propagation and terrain analysis tool for the spectrum
       between 20 MHz and 20 GHz.  SPLAT! is free software, and is designed for operation on Unix
       and Linux-based workstations.  Redistribution and/or modification is permitted  under  the
       terms  of  the  GNU  General  Public License, Version 2, as published by the Free Software
       Foundation.  Adoption of SPLAT!  source code in proprietary or closed-source  applications
       is a violation of this license and is strictly forbidden.

       SPLAT!  is  distributed  in  the  hope  that  it will be useful, but WITHOUT ANY WARRANTY,
       without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR  PURPOSE.
       See the GNU General Public License for more details.

INTRODUCTION

       Applications  of  SPLAT!  include  the  visualization, design, and link budget analysis of
       wireless Wide Area Networks (WANs), commercial and  amateur  radio  communication  systems
       above  20  MHz,  microwave links, frequency coordination and interference studies, and the
       prediction of analog and digital terrestrial radio and television contour regions.

       SPLAT! provides RF site engineering data such  as  great  circle  distances  and  bearings
       between  sites,  antenna  elevation angles (uptilt), depression angles (downtilt), antenna
       height above mean sea level, antenna height above average  terrain,  bearings,  distances,
       and  elevations  to  known  obstructions,  Irregular  Terrain  Model path attenuation, and
       received signal strength.  In addition, the minimum antenna height requirements needed  to
       clear  terrain,  the  first  Fresnel  zone, and any user-definable percentage of the first
       Fresnel zone are also provided.

       SPLAT! produces reports, graphs, and high resolution topographic maps that depict line-of-
       sight  paths,  and  regional path loss and signal strength contours through which expected
       coverage areas of transmitters and repeater systems  can  be  obtained.   When  performing
       line-of-sight   and   Irregular  Terrain  Model  analyses  in  situations  where  multiple
       transmitter or repeater sites are employed, SPLAT! determines individual and mutual  areas
       of coverage within the network specified.

INPUT FILES

       SPLAT!  is a command-line driven application and reads input data through a number of data
       files.  Some files are mandatory for successful execution of the program, while others are
       optional.   Mandatory  files  include  digital  elevation topography models in the form of
       SPLAT Data Files (SDF files), site location files (QTH files), and Irregular Terrain Model
       parameter  files  (LRP  files).   Optional files include city location files, cartographic
       boundary files, user-defined terrain files,  path  loss  input  files,  antenna  radiation
       pattern files, and color definition files.

SPLAT DATA FILES

       SPLAT!  imports  topographic data in the form of SPLAT Data Files (SDFs).  These files may
       be generated from a number of information sources.  In the United States, SPLAT Data Files
       can be generated through U.S.  Geological Survey Digital Elevation Models (DEMs) using the
       postdownload and usgs2sdf utilities included with SPLAT!.  USGS Digital  Elevation  Models
       compatible      with      these      utilities      may      be      downloaded      from:
       http://edcftp.cr.usgs.gov/pub/data/DEM/250/.

       Significantly better resolution and accuracy can be  obtained  through  the  use  of  SRTM
       Version 2 digital elevation models, especially when supplemented by USGS-derived SDF data.
       These one-degree by one-degree models are the product of the Space  Shuttle  STS-99  Radar
       Topography Mission, and are available for most populated regions of the Earth.  SPLAT Data
       Files may be generated from 3 arc-second SRTM-3 data using the included srtm2sdf  utility.
       SRTM-3    Version    2    data    may    be   obtained   through   anonymous   FTP   from:
       ftp://e0srp01u.ecs.nasa.gov:21/srtm/version2/SRTM3/

       Note that SRTM filenames refer to the latitude and longitude of the  southwest  corner  of
       the topographic dataset contained within the file.  Therefore, the region of interest must
       lie north and east of the latitude and longitude provided in the SRTM filename.

       The srtm2sdf utility may  also  be  used  to  convert  3-arc  second  SRTM  data  in  Band
       Interleaved by Line (.BIL) format for use with SPLAT!.  This data is available via the web
       at: http://seamless.usgs.gov/website/seamless/

       Band Interleaved by Line data  must  be  downloaded  in  a  very  specific  manner  to  be
       compatible  with  srtm2sdf  and  SPLAT!.   Please  consult  srtm2sdf's  documentation  for
       instructions on downloading .BIL topographic data through the USGS's Seamless Web Site.

       Even greater resolution and accuracy can be obtained by using 1 arc-second SRTM-1  Version
       2  topography  data.  This data is available for the United States and its territories and
       possessions,           and           may           be           downloaded           from:
       ftp://e0srp01u.ecs.nasa.gov:21/srtm/version2/SRTM1/

       High resolution SDF files for use with SPLAT! HD may be generated from data in this format
       using the srtm2sdf-hd utility.

       Despite the higher accuracy that SRTM data has to offer,  some  voids  in  the  data  sets
       exist.   When voids are detected, the srtm2sdf and srtm2sdf-hd utilities replace them with
       corresponding data found in usgs2sdf generated SDF files.  If USGS-derived SDF data is not
       available, voids are handled through adjacent pixel averaging, or direct replacement.

       SPLAT Data Files contain integer value topographic elevations in meters referenced to mean
       sea level for 1-degree by 1-degree regions of the Earth.  SDF files can be read by  SPLAT!
       in  either  standard  format  (.sdf)  as generated directly by the usgs2sdf, srtm2sdf, and
       srtm2sdf-hd utilities, or in bzip2 compressed format (.sdf.bz2).  Since uncompressed files
       can  be  read  slightly  faster  than files that have been compressed, SPLAT! searches for
       needed SDF data in uncompressed format first.  If uncompressed  data  cannot  be  located,
       SPLAT!  then searches for data in bzip2 compressed format.  If no compressed SDF files can
       be found for the region requested, SPLAT! assumes the  region  is  over  water,  and  will
       assign an elevation of sea-level to these areas.

       This  feature of SPLAT! makes it possible to perform path analysis not only over land, but
       also between coastal areas not represented by Digital Elevation Model data.  However, this
       behavior  of  SPLAT!   underscores the importance of having all the SDF files required for
       the region being analyzed if meaningful results are to be expected.

SITE LOCATION (QTH) FILES

       SPLAT! imports site location information of transmitter and receiver sites analyzed by the
       program  from ASCII files having a .qth extension.  QTH files contain the site's name, the
       site's latitude (positive if  North  of  the  equator,  negative  if  South),  the  site's
       longitude  (in degrees West, 0 to 360 degrees, or degrees East 0 to -360 degrees), and the
       site's antenna height above ground level (AGL),  each  separated  by  a  single  line-feed
       character.   The  antenna height is assumed to be specified in feet unless followed by the
       letter m or the word meters in  either  upper  or  lower  case.   Latitude  and  longitude
       information  may be expressed in either decimal format (74.6864) or degree, minute, second
       (DMS) format (74 41 11.0).

       For example, a site location file  describing  television  station  WNJT-DT,  Trenton,  NJ
       (wnjt-dt.qth) might read as follows:

               WNJT-DT
               40.2828
               74.6864
               990.00

       Each  transmitter and receiver site analyzed by SPLAT! must be represented by its own site
       location (QTH) file.

IRREGULAR TERRAIN MODEL PARAMETER (LRP) FILES

       Irregular Terrain Model Parameter data files are required for SPLAT!  to determine RF path
       loss,  field  strength,  or  received  signal power level in either point-to-point or area
       prediction mode.  Irregular Terrain Model parameter data is read  from  files  having  the
       same  base  name  as the transmitter site QTH file, but with a .lrp extension.  SPLAT! LRP
       files share the following format (wnjt-dt.lrp):

               15.000  ; Earth Dielectric Constant (Relative permittivity)
               0.005   ; Earth Conductivity (Siemens per meter)
               301.000 ; Atmospheric Bending Constant (N-units)
               647.000 ; Frequency in MHz (20 MHz to 20 GHz)
               5       ; Radio Climate (5 = Continental Temperate)
               0       ; Polarization (0 = Horizontal, 1 = Vertical)
               0.50    ; Fraction of situations (50% of locations)
               0.90    ; Fraction of time (90% of the time)
               46000.0 ; Effective Radiated Power (ERP) in Watts (optional)

       If an LRP file corresponding to the tx_site QTH file cannot be  found,  SPLAT!  scans  the
       current  working  directory  for the file "splat.lrp".  If this file cannot be found, then
       default parameters will be  assigned  by  SPLAT!  and  a  corresponding  "splat.lrp"  file
       containing these default parameters will be written to the current working directory.  The
       generated "splat.lrp" file can then be edited by the user as needed.

       Typical Earth dielectric constants and conductivity values are as follows:
                                  Dielectric Constant  Conductivity
               Salt water       :        80                5.000
               Good ground      :        25                0.020
               Fresh water      :        80                0.010
               Marshy land      :        12                0.007
               Farmland, forest :        15                0.005
               Average ground   :        15                0.005
               Mountain, sand   :        13                0.002
               City             :         5                0.001
               Poor ground      :         4                0.001

       Radio climate codes used by SPLAT! are as follows:

               1: Equatorial (Congo)
               2: Continental Subtropical (Sudan)
               3: Maritime Subtropical (West coast of Africa)
               4: Desert (Sahara)
               5: Continental Temperate
               6: Maritime Temperate, over land (UK and west coasts of US & EU)
               7: Maritime Temperate, over sea

       The Continental Temperate climate is common to large land masses in  the  temperate  zone,
       such  as  the  United  States.   For paths shorter than 100 km, there is little difference
       between Continental and Maritime Temperate climates.

       The seventh and eighth parameters in the .lrp file correspond to the statistical  analysis
       provided  by  the  ITM  model.   In this example, SPLAT! will return the maximum path loss
       occurring 50% of the time (fraction of time, or Time Variability)  in  90%  of  situations
       (fraction  of  situations, or Location Variability).  This is often denoted as F(50,90) in
       Longley-Rice studies.  In the United States, an F(50,90) criteria is  typically  used  for
       digital  television  (8-level  VSB  modulation),  while  F(50,50) is used for analog (VSB-
       AM+NTSC) broadcasts.

       For  further  information  on  ITM  propagation  model  parameters,   please   refer   to:
       http://flattop.its.bldrdoc.gov/itm.html                                                and
       http://www.softwright.com/faq/engineering/prop_longley_rice.html

       The last parameter in the .lrp file corresponds to the  transmitter's  Effective  Radiated
       Power  (ERP),  and  is  optional.   If  it  is included in the .lrp file, then SPLAT! will
       compute received signal strength levels and field strength level contours when  performing
       ITM  studies.   If  the  parameter  is  omitted,  path  loss is computed instead.  The ERP
       provided in the .lrp file can be overridden by using SPLAT!'s  -erp  command-line  switch.
       If  the  .lrp  file  contains an ERP parameter and the generation of path loss rather than
       field strength contours is desired, the ERP can be assigned to zero using the -erp  switch
       without having to edit the .lrp file to accomplish the same result.

CITY LOCATION FILES

       The  names  and  locations  of  cities,  tower  sites,  or other points of interest may be
       imported and plotted on topographic maps generated by SPLAT!.  SPLAT! imports the names of
       cities  and  locations  from  ASCII  files  containing  the  location  of interest's name,
       latitude, and longitude.  Each field is separated by a comma.  Each record is separated by
       a single line feed character.  As was the case with the .qth files, latitude and longitude
       information may be entered in either decimal or degree, minute, second (DMS) format.

       For example (cities.dat):

               Teaneck, 40.891973, 74.014506
               Tenafly, 40.919212, 73.955892
               Teterboro, 40.859511, 74.058908
               Tinton Falls, 40.279966, 74.093924
               Toms River, 39.977777, 74.183580
               Totowa, 40.906160, 74.223310
               Trenton, 40.219922, 74.754665

       A total of five separate city data files may be imported at a time, and there is no  limit
       to  the size of these files.  SPLAT! reads city data on a "first come/first served" basis,
       and plots only those locations whose annotations  do  not  conflict  with  annotations  of
       locations read earlier in the current city data file, or in previous files.  This behavior
       minimizes clutter in SPLAT! generated topographic maps, but also mandates  that  important
       locations  be  placed toward the beginning of the first city data file, and locations less
       important be positioned further down the list or in subsequent data files.

       City data files may be generated manually using  any  text  editor,  imported  from  other
       sources,  or derived from data available from the U.S. Census Bureau using the citydecoder
       utility included with SPLAT!.  Such data is available free of charge via the Internet  at:
       http://www.census.gov/geo/www/cob/bdy_files.html, and must be in ASCII format.

CARTOGRAPHIC BOUNDARY DATA FILES

       Cartographic  boundary  data  may  also  be  imported  to  plot  the boundaries of cities,
       counties, or states on topographic maps generated by SPLAT!.  Such data  must  be  of  the
       form  of  ARC/INFO Ungenerate (ASCII Format) Metadata Cartographic Boundary Files, and are
       available    from    the    U.S.     Census    Bureau     via     the     Internet     at:
       http://www.census.gov/geo/www/cob/co2000.html#ascii                                    and
       http://www.census.gov/geo/www/cob/pl2000.html#ascii.    A   total   of    five    separate
       cartographic  boundary  files  may  be  imported at a time.  It is not necessary to import
       state boundaries if county boundaries have already been imported.

PROGRAM OPERATION

       SPLAT! is invoked via the command-line using a series of switches  and  arguments.   Since
       SPLAT!  is  a  CPU  and  memory  intensive  application,  this type of interface minimizes
       overhead and lends itself well to scripted (batch) operations.  SPLAT!'s  CPU  and  memory
       scheduling priority may be modified through the use of the Unix nice command.

       The  number  and  type  of  switches  passed to SPLAT! determine its mode of operation and
       method of output data generation.  Nearly all of SPLAT!'s switches may be cascaded in  any
       order on the command line when invoking the program.

       Simply  typing  splat  on  the command line will return a summary of SPLAT!'s command line
       options:

                    --==[ SPLAT! v1.4.0 Available Options... ]==--

            -t txsite(s).qth (max of 4 with -c, max of 30 with -L)
            -r rxsite.qth
            -c plot coverage of TX(s) with an RX antenna at X feet/meters AGL
            -L plot path loss map of TX based on an RX at X feet/meters AGL
            -s filename(s) of city/site file(s) to import (5 max)
            -b filename(s) of cartographic boundary file(s) to import (5 max)
            -p filename of terrain profile graph to plot
            -e filename of terrain elevation graph to plot
            -h filename of terrain height graph to plot
            -H filename of normalized terrain height graph to plot
            -l filename of path loss graph to plot
            -o filename of topographic map to generate (.ppm)
            -u filename of user-defined terrain file to import
            -d sdf file directory path (overrides path in ~/.splat_path file)
            -m earth radius multiplier
            -n do not plot LOS paths in .ppm maps
            -N do not produce unnecessary site or obstruction reports
            -f frequency for Fresnel zone calculation (MHz)
            -R modify default range for -c or -L (miles/kilometers)
           -sc display smooth rather than quantized contour levels
           -db threshold beyond which contours will not be displayed
           -nf do not plot Fresnel zones in height plots
           -fz Fresnel zone clearance percentage (default = 60)
           -gc ground clutter height (feet/meters)
          -ngs display greyscale topography as white in .ppm files
          -erp override ERP in .lrp file (Watts)
          -ano name of alphanumeric output file
          -ani name of alphanumeric input file
          -udt filename of user defined terrain input file
          -kml generate Google Earth (.kml) compatible output
          -geo generate an Xastir .geo georeference file (with .ppm output)
          -dbm plot signal power level contours rather than field strength
        -gpsav preserve gnuplot temporary working files after  SPLAT!  execution  -metric  employ
       metric  rather  than  imperial units for all user I/O -olditm invoke older ITM propagation
       model rather than the newer ITWOM

       The command-line options for splat and splat-hd are identical.

       SPLAT! operates in two distinct modes: point-to-point  mode,  and  area  prediction  mode.
       Either  a  line-of-sight (LOS) or Irregular Terrain (ITM) propagation model may be invoked
       by the user.  True Earth, four-thirds Earth, or any other user-defined Earth radius may be
       specified when performing line-of-sight analysis.

POINT-TO-POINT ANALYSIS

       SPLAT!  may  be  used to perform line-of-sight terrain analysis between two specified site
       locations.  For example:

       splat -t tx_site.qth -r rx_site.qth

       invokes a line-of-sight terrain analysis between the transmitter specified in  tx_site.qth
       and receiver specified in rx_site.qth using a True Earth radius model, and writes a SPLAT!
       Path Analysis Report to the current working directory.  The report contains details of the
       transmitter  and  receiver sites, and identifies the location of any obstructions detected
       along the line-of-sight path.  If an obstruction can be cleared  by  raising  the  receive
       antenna  to  a  greater altitude, SPLAT! will indicate the minimum antenna height required
       for a  line-of-sight  path  to  exist  between  the  transmitter  and  receiver  locations
       specified.  Note that imperial units (miles, feet) are specified unless the -metric switch
       is added to SPLAT!'s command line options:

       splat -t tx_site.qth -r rx_site.qth -metric

       If the antenna must be raised a significant amount, this  determination  may  take  a  few
       moments.   Note  that  the  results provided are the minimum necessary for a line-of-sight
       path to exist, and in the case of this simple example, do not take Fresnel zone  clearance
       requirements into consideration.

       qth  extensions  are  assumed by SPLAT! for QTH files, and are optional when specifying -t
       and -r arguments on the command-line.  SPLAT! automatically reads  all  SPLAT  Data  Files
       necessary  to  conduct the terrain analysis between the sites specified.  SPLAT!  searches
       for the required SDF files in the current working directory first.  If  the  needed  files
       are not found, SPLAT! then searches in the path specified by the -d command-line switch:

       splat -t tx_site -r rx_site -d /cdrom/sdf/

       An  external  directory  path  may  be specified by placing a ".splat_path" file under the
       user's home directory.  This file must contain the full directory path of last  resort  to
       all the SDF files.  The path in the $HOME/.splat_path file must be of the form of a single
       line of ASCII text:

       /opt/splat/sdf/

       and can be generated using any text editor.

       A graph of the terrain profile  between  the  receiver  and  transmitter  locations  as  a
       function of distance from the receiver can be generated by adding the -p switch:

       splat -t tx_site -r rx_site -p terrain_profile.png

       SPLAT! invokes gnuplot when generating graphs.  The filename extension specified to SPLAT!
       determines the format of the graph produced.   .png  will  produce  a  640x480  color  PNG
       graphic  file, while .ps or .postscript will produce postscript output.  Output in formats
       such as GIF, Adobe Illustrator, AutoCAD dxf, LaTeX, and many others are available.  Please
       consult  gnuplot,  and  gnuplot's  documentation  for  details on all the supported output
       formats.

       A graph of elevations subtended by the terrain between the receiver and transmitter  as  a
       function of distance from the receiver can be generated by using the -e switch:

       splat -t tx_site -r rx_site -e elevation_profile.png

       The  graph  produced  using  this  switch  illustrates the elevation and depression angles
       resulting from the terrain between the receiver's location and the transmitter  site  from
       the  perspective  of  the receiver's location.  A second trace is plotted between the left
       side of the graph (receiver's location) and the location of the  transmitting  antenna  on
       the  right.   This trace illustrates the elevation angle required for a line-of-sight path
       to exist between the receiver and transmitter locations.   If  the  trace  intersects  the
       elevation  profile  at  any point on the graph, then this is an indication that a line-of-
       sight path does not exist under the conditions given, and the obstructions can be  clearly
       identified on the graph at the point(s) of intersection.

       A  graph  illustrating  terrain  height  referenced  to  a  line-of-sight path between the
       transmitter and receiver may be generated using the -h switch:

       splat -t tx_site -r rx_site -h height_profile.png

       A terrain height plot normalized to the transmitter and receiver antenna  heights  can  be
       obtained using the -H switch:

       splat -t tx_site -r rx_site -H normalized_height_profile.png

       A contour of the Earth's curvature is also plotted in this mode.

       The  first  Fresnel Zone, and 60% of the first Fresnel Zone can be added to height profile
       graphs by adding the -f switch, and specifying a frequency (in MHz) at which  the  Fresnel
       Zone should be modeled:

       splat -t tx_site -r rx_site -f 439.250 -H normalized_height_profile.png

       Fresnel Zone clearances other 60% can be specified using the -fz switch as follows:

       splat -t tx_site -r rx_site -f 439.250 -fz 75 -H height_profile2.png

       A graph showing ITM path loss may be plotted using the -l switch:

       splat -t tx_site -r rx_site -l path_loss_profile.png

       As before, adding the -metric switch forces the graphs to be plotted using metric units of
       measure.  The -gpsav switch instructs SPLAT! to preserve (rather than delete) the  gnuplot
       working files generated during SPLAT! execution, allowing the user to edit these files and
       re-run gnuplot if desired.

       When performing a point-to-point analysis, a SPLAT! Path Analysis Report is  generated  in
       the  form of a text file with a .txt filename extension.  The report contains bearings and
       distances between the transmitter and receiver, as well as the  free-space  and  ITM  path
       loss  for the path being analyzed.  The mode of propagation for the path is given as Line-
       of-Sight, Single Horizon, Double Horizon, Diffraction Dominant, or Troposcatter  Dominant.
       Additionally,  if  the  receiver  is located at the peak of a single obstruction or at the
       peak of a second obstruction, SPLAT! will report  RX  at  Peak  Terrain  Along  Path  when
       operating under the ITWOM propagation model.

       Distances  and  locations  to  known  obstructions  along the path between transmitter and
       receiver are also provided.  If the transmitter's effective radiated power is specified in
       the  transmitter's  corresponding  .lrp  file,  then predicted signal strength and antenna
       voltage at the receiving location is also provided in the Path Analysis Report.

       To determine the signal-to-noise (SNR) ratio  at  remote  location  where  random  Johnson
       (thermal) noise is the primary limiting factor in reception:

       SNR = T - NJ - L + G - NF

       where  T  is  the  ERP  of  the transmitter in dBW in the direction of the receiver, NJ is
       Johnson Noise in dBW (-136 dBW for a 6  MHz  television  channel),  L  is  the  path  loss
       provided by SPLAT!  in dB (as a positive number), G is the receive antenna gain in dB over
       isotropic, and NF is the receiver noise figure in dB.

       T may be computed as follows:

       T = TI + GT

       where TI is actual amount of RF power delivered to the transmitting antenna in dBW, GT  is
       the  transmitting  antenna  gain (over isotropic) in the direction of the receiver (or the
       horizon if the receiver is over the horizon).

       To compute how much more signal is available over the minimum to necessary  to  achieve  a
       specific signal-to-noise ratio:

       Signal_Margin = SNR - S

       where  S  is the minimum required SNR ratio (15.5 dB for ATSC (8-level VSB) DTV, 42 dB for
       analog NTSC television).

       A topographic map may be generated by SPLAT! to visualize the path between the transmitter
       and  receiver  sites  from  yet another perspective.  Topographic maps generated by SPLAT!
       display elevations using a  logarithmic  grayscale,  with  higher  elevations  represented
       through  brighter  shades  of  gray.  The dynamic range of the image is scaled between the
       highest and lowest elevations present in the map.  The only  exception  to  this  is  sea-
       level, which is represented using the color blue.

       Topographic output is invoked using the -o switch:

       splat -t tx_site -r rx_site -o topo_map.ppm

       The .ppm extension on the output filename is assumed by SPLAT!, and is optional.

       In  this  example,  topo_map.ppm  will  illustrate  the  locations  of the transmitter and
       receiver sites specified.  In addition, the great circle path between the two  sites  will
       be  drawn  over  locations  for  which an unobstructed path exists to the transmitter at a
       receiving antenna height equal to that of the receiver site (specified in rx_site.qth).

       It may desirable to populate the topographic map with names and locations of cities, tower
       sites,  or  other  important  locations.  A city file may be passed to SPLAT! using the -s
       switch:

       splat -t tx_site -r rx_site -s cities.dat -o topo_map

       Up to five separate city files may be passed to SPLAT! at a time following the -s switch.

       County and state boundaries may be added to the map by specifying up to five  U.S.  Census
       Bureau cartographic boundary files using the -b switch:

       splat -t tx_site -r rx_site -b co34_d00.dat -o topo_map

       In  situations where multiple transmitter sites are in use, as many as four site locations
       may be passed to SPLAT! at a time for analysis:

       splat -t tx_site1 tx_site2 tx_site3 tx_site4 -r rx_site -p profile.png

       In this example, four separate terrain profiles and obstruction reports will be  generated
       by  SPLAT!.   A  single topographic map can be specified using the -o switch, and line-of-
       sight paths between each transmitter and the receiver site indicated will be  produced  on
       the  map,  each in its own color.  The path between the first transmitter specified to the
       receiver will be in green, the path between the second transmitter and the  receiver  will
       be in cyan, the path between the third transmitter and the receiver will be in violet, and
       the path between the fourth transmitter and the receiver will be in sienna.

       SPLAT! generated topographic maps are 24-bit TrueColor Portable PixMap (PPM) images.  They
       may  be  viewed,  edited,  or  converted to other graphic formats by popular image viewing
       applications such as xv,  The  GIMP,  ImageMagick,  and  XPaint.   PNG  format  is  highly
       recommended for lossless compressed storage of SPLAT!  generated topographic output files.
       ImageMagick's command-line utility easily converts SPLAT!'s PPM files to PNG format:

       convert splat_map.ppm splat_map.png

       Another   excellent   PPM   to    PNG    command-line    utility    is    available    at:
       http://www.libpng.org/pub/png/book/sources.html.   As  a  last  resort,  PPM  files may be
       compressed using the bzip2 utility, and read directly by The GIMP in this format.

       The -ngs option assigns all terrain to the color  white,  and  can  be  used  when  it  is
       desirable to generate a map that is devoid of terrain:

       splat -t tx_site -r rx_site -b co34_d00.dat -ngs -o white_map

       The  resulting  .ppm  image  file  can  be  converted  to  .png  format with a transparent
       background using ImageMagick's convert utility:

       convert -transparent "#FFFFFF" white_map.ppm transparent_map.png

REGIONAL COVERAGE ANALYSIS

       SPLAT! can analyze a transmitter or repeater site, or network of sites,  and  predict  the
       regional  coverage  for  each  site  specified.   In  this  mode,  SPLAT!  can  generate a
       topographic map displaying the geometric line-of-sight coverage area of the sites based on
       the  location  of  each site and the height of receive antenna wishing to communicate with
       the site in question.  A regional analysis may be performed by SPLAT! using the -c  switch
       as follows:

       splat -t tx_site -c 30.0 -s cities.dat -b co34_d00.dat -o tx_coverage

       In   this  example,  SPLAT!  generates  a  topographic  map  called  tx_coverage.ppm  that
       illustrates  the  predicted  line-of-sight  regional  coverage  of  tx_site  to  receiving
       locations  having  antennas  30.0 feet above ground level (AGL).  If the -metric switch is
       used, the argument following the -c switch is interpreted as being in meters  rather  than
       in  feet.   The  contents  of  cities.dat  are plotted on the map, as are the cartographic
       boundaries contained in the file co34_d00.dat.

       When plotting line-of-sight paths and areas of regional coverage, SPLAT! by  default  does
       not  account  for  the  effects  of  atmospheric  bending.   However, this behavior may be
       modified by using the Earth radius multiplier (-m) switch:

       splat -t wnjt-dt -c 30.0 -m 1.333 -s cities.dat -b counties.dat -o map.ppm

       An earth radius multiplier of 1.333 instructs SPLAT! to use the "four-thirds earth"  model
       for  line-of-sight  propagation  analysis.  Any appropriate earth radius multiplier may be
       selected by the user.

       When performing a regional analysis, SPLAT! generates  a  site  report  for  each  station
       analyzed.   SPLAT!  site  reports  contain  details of the site's geographic location, its
       height above mean sea level, the antenna's height above  mean  sea  level,  the  antenna's
       height  above average terrain, and the height of the average terrain calculated toward the
       bearings of 0, 45, 90, 135, 180, 225, 270, and 315 degrees azimuth.

DETERMINING MULTIPLE REGIONS OF LOS COVERAGE

       SPLAT! can also display  line-of-sight  coverage  areas  for  as  many  as  four  separate
       transmitter sites on a common topographic map.  For example:

       splat -t site1 site2 site3 site4 -c 10.0 -metric -o network.ppm

       plots  the  regional  line-of-sight  coverage of site1, site2, site3, and site4 based on a
       receive antenna located 10.0 meters above ground level.  A topographic map is then written
       to  the file network.ppm.  The line-of-sight coverage area of the transmitters are plotted
       as follows in the colors indicated (along with their corresponding RGB values in decimal):

           site1: Green (0,255,0)
           site2: Cyan (0,255,255)
           site3: Medium Violet (147,112,219)
           site4: Sienna 1 (255,130,71)

           site1 + site2: Yellow (255,255,0)
           site1 + site3: Pink (255,192,203)
           site1 + site4: Green Yellow (173,255,47)
           site2 + site3: Orange (255,165,0)
           site2 + site4: Dark Sea Green 1 (193,255,193)
           site3 + site4: Dark Turquoise (0,206,209)

           site1 + site2 + site3: Dark Green (0,100,0)
           site1 + site2 + site4: Blanched Almond (255,235,205)
           site1 + site3 + site4: Medium Spring Green (0,250,154)
           site2 + site3 + site4: Tan (210,180,140)

           site1 + site2 + site3 + site4: Gold2 (238,201,0)

       If separate .qth files are generated, each representing  a  common  site  location  but  a
       different antenna height, a single topographic map illustrating the regional coverage from
       as many as four separate locations on a single tower may be generated by SPLAT!.

PATH LOSS ANALYSIS

       If the -c switch is replaced by a -L switch, an ITM path loss map for a  transmitter  site
       may be generated:

       splat -t wnjt -L 30.0 -s cities.dat -b co34_d00.dat -o path_loss_map

       In  this  mode,  SPLAT! generates a multi-color map illustrating expected signal levels in
       areas surrounding the transmitter site.  A legend at the bottom of the map correlates each
       color with a specific path loss range in decibels.

       The  -db  switch allows a threshold to be set beyond which contours will not be plotted on
       the map.  For example, if a path loss beyond -140 dB is irrelevant  to  the  survey  being
       conducted,  SPLAT!'s path loss plot can be constrained to the region bounded by the 140 dB
       attenuation contour as follows:

       splat -t wnjt-dt -L 30.0 -s cities.dat -b co34_d00.dat -db 140 -o plot.ppm

       The path loss contour threshold  may  be  expressed  as  either  a  positive  or  negative
       quantity.

       The  path  loss  analysis  range  may be modified to a user-specific distance using the -R
       switch.  The argument must be given in miles (or  kilometers  if  the  -metric  switch  is
       used).   If  a  range  wider  than the generated topographic map is specified, SPLAT! will
       perform ITM path loss calculations between all four corners of the area prediction map.

       The colors used to illustrate contour regions in SPLAT! generated  coverage  maps  may  be
       tailored  by  the  user  by creating or modifying SPLAT!'s color definition files.  SPLAT!
       color definition files have the same base name as the transmitter's .qth file,  but  carry
       .lcf,  .scf,  and  .dcf  extensions.   If the necessary file does not exist in the current
       working when SPLAT!  is run, a file containing default color definition parameters that is
       suitable for manual editing by the user is written into the current directory.

       When a regional ITM analysis is performed and the transmitter's ERP is not specified or is
       zero, a .lcf path loss color definition file corresponding to the transmitter site  (.qth)
       is read by SPLAT! from the current working directory.  If a .lcf file corresponding to the
       transmitter site is not found, then a default file suitable for manual editing by the user
       is automatically generated by SPLAT!.

       A path loss color definition file possesses the following structure (wnjt-dt.lcf):

        ; SPLAT! Auto-generated Path-Loss Color Definition ("wnjt-dt.lcf") File
        ;
        ; Format for the parameters held in this file is as follows:
        ;
        ;    dB: red, green, blue
        ;
        ; ...where "dB" is the path loss (in dB) and
        ; "red", "green", and "blue" are the corresponding RGB color
        ; definitions ranging from 0 to 255 for the region specified.
        ;
        ; The following parameters may be edited and/or expanded
        ; for future runs of SPLAT!  A total of 32 contour regions
        ; may be defined in this file.
        ;
        ;
         80: 255,   0,   0
         90: 255, 128,   0
        100: 255, 165,   0
        110: 255, 206,   0
        120: 255, 255,   0
        130: 184, 255,   0
        140:   0, 255,   0
        150:   0, 208,   0
        160:   0, 196, 196
        170:   0, 148, 255
        180:  80,  80, 255
        190:   0,  38, 255
        200: 142,  63, 255
        210: 196,  54, 255
        220: 255,   0, 255
        230: 255, 194, 204

       If  the  path  loss is less than 80 dB, the color Red (RGB = 255, 0, 0) is assigned to the
       region.  If the path loss is greater than or equal to 80 dB, but less  than  90  db,  then
       Dark  Orange (255, 128, 0) is assigned to the region.  Orange (255, 165, 0) is assigned to
       regions having a path loss greater than or equal to 90 dB, but less than 100  dB,  and  so
       on.   Greyscale  terrain  is displayed beyond the 230 dB path loss contour. Adding the -sc
       switch will smooth the transitions between the specified quantized contour levels.

FIELD STRENGTH ANALYSIS

       If the transmitter's effective radiated power (ERP) is specified in the transmitter's .lrp
       file,  or  expressed  on  the  command-line using the -erp switch, field strength contours
       referenced to decibels over one microvolt per meter (dBuV/m) rather  than  path  loss  are
       produced:

       splat -t wnjt-dt -L 30.0 -erp 46000 -db 30 -o plot.ppm

       The  -db  switch  can  be  used  in this mode as before to limit the extent to which field
       strength contours are plotted.   When  plotting  field  strength  contours,  however,  the
       argument given is interpreted as being expressed in dBuV/m.

       SPLAT!  field strength color definition files share a very similar structure to .lcf files
       used for plotting path loss:

        ; SPLAT! Auto-generated Signal Color Definition ("wnjt-dt.scf") File
        ;
        ; Format for the parameters held in this file is as follows:
        ;
        ;    dBuV/m: red, green, blue
        ;
        ; ...where "dBuV/m" is the signal strength (in dBuV/m) and
        ; "red", "green", and "blue" are the corresponding RGB color
        ; definitions ranging from 0 to 255 for the region specified.
        ;
        ; The following parameters may be edited and/or expanded
        ; for future runs of SPLAT!  A total of 32 contour regions
        ; may be defined in this file.
        ;
        ;
        128: 255,   0,   0
        118: 255, 165,   0
        108: 255, 206,   0
         98: 255, 255,   0
         88: 184, 255,   0
         78:   0, 255,   0
         68:   0, 208,   0
         58:   0, 196, 196
         48:   0, 148, 255
         38:  80,  80, 255
         28:   0,  38, 255
         18: 142,  63, 255
          8: 140,   0, 128

       If the signal strength is greater than or equal to 128  dB  over  1  microvolt  per  meter
       (dBuV/m),  the  color Red (255, 0, 0) is displayed for the region.  If the signal strength
       is greater than or equal to 118 dBuV/m, but less than 128 dBuV/m, then  the  color  Orange
       (255,  165,  0)  is displayed, and so on.  Greyscale terrain is displayed for regions with
       signal strengths less than 8 dBuV/m.

       Signal strength contours for some common VHF and UHF broadcasting services in  the  United
       States are as follows:

              Analog Television Broadcasting
              ------------------------------
              Channels 2-6:       City Grade: >= 74 dBuV/m
                                     Grade A: >= 68 dBuV/m
                                     Grade B: >= 47 dBuV/m
              --------------------------------------------
              Channels 7-13:      City Grade: >= 77 dBuV/m
                                     Grade A: >= 71 dBuV/m
                                     Grade B: >= 56 dBuV/m
              --------------------------------------------
              Channels 14-69:   Indoor Grade: >= 94 dBuV/m
                                  City Grade: >= 80 dBuV/m
                                     Grade A: >= 74 dBuV/m
                                     Grade B: >= 64 dBuV/m

              Digital Television Broadcasting
              -------------------------------
              Channels 2-6:       City Grade: >= 35 dBuV/m
                           Service Threshold: >= 28 dBuV/m
              --------------------------------------------
              Channels 7-13:      City Grade: >= 43 dBuV/m
                           Service Threshold: >= 36 dBuV/m
              --------------------------------------------
              Channels 14-69:     City Grade: >= 48 dBuV/m
                           Service Threshold: >= 41 dBuV/m

              NOAA Weather Radio (162.400 - 162.550 MHz)
              ------------------------------------------
                         Reliable: >= 18 dBuV/m
                     Not reliable: <  18 dBuV/m
              Unlikely to receive: <  0 dBuV/m

              FM Radio Broadcasting (88.1 - 107.9 MHz)
              ----------------------------------------
              Analog Service Contour:  60 dBuV/m
              Digital Service Contour: 65 dBuV/m

RECEIVED POWER LEVEL ANALYSIS

       If the transmitter's effective radiated power (ERP) is specified in the transmitter's .lrp
       file, or expressed on the command-line using the -erp  switch,  and  the  -dbm  switch  is
       invoked, received power level contours referenced to decibels over one milliwatt (dBm) are
       produced:

       splat -t wnjt-dt -L 30.0 -erp 46000 -dbm -db -100 -o plot.ppm

       The -db switch can be used to limit the extent to which received power level contours  are
       plotted.   When  plotting power level contours, the argument given is interpreted as being
       expressed in dBm.

       SPLAT! received power level color definition files share a very similar structure  to  the
       color  definition  files  described  earlier,  except  that the power levels in dBm may be
       either positive or negative, and are limited to a range between +40 dBm and -200 dBm:

        ; SPLAT! Auto-generated DBM Signal Level Color Definition ("wnjt-dt.dcf") File
        ;
        ; Format for the parameters held in this file is as follows:
        ;
        ;    dBm: red, green, blue
        ;
        ; ...where "dBm" is the received signal power level between +40 dBm
        ; and -200 dBm, and "red", "green", and "blue" are the corresponding
        ; RGB color definitions ranging from 0 to 255 for the region specified.
        ;
        ; The following parameters may be edited and/or expanded
        ; for future runs of SPLAT!  A total of 32 contour regions
        ; may be defined in this file.
        ;
        ;
          +0: 255,   0,   0
         -10: 255, 128,   0
         -20: 255, 165,   0
         -30: 255, 206,   0
         -40: 255, 255,   0
         -50: 184, 255,   0
         -60:   0, 255,   0
         -70:   0, 208,   0
         -80:   0, 196, 196
         -90:   0, 148, 255
        -100:  80,  80, 255
        -110:   0,  38, 255
        -120: 142,  63, 255
        -130: 196,  54, 255
        -140: 255,   0, 255
        -150: 255, 194, 204

ANTENNA RADIATION PATTERN PARAMETERS

       Normalized field voltage patterns for a transmitting  antenna's  horizontal  and  vertical
       planes  are  imported  automatically  into  SPLAT!  when  a  path loss, field strength, or
       received power level coverage analysis is performed.  Antenna pattern data is read from  a
       pair of files having the same base name as the transmitter and LRP files, but with .az and
       .el extensions for azimuth and  elevation  pattern  files,  respectively.   Specifications
       regarding  pattern  rotation (if any) and mechanical beam tilt and tilt direction (if any)
       are also contained within SPLAT! antenna pattern files.

       For example, the first few lines of a SPLAT! azimuth pattern file might appear as  follows
       (kvea.az):

               183.0
               0       0.8950590
               1       0.8966406
               2       0.8981447
               3       0.8995795
               4       0.9009535
               5       0.9022749
               6       0.9035517
               7       0.9047923
               8       0.9060051

       The  first  line  of  the  .az  file  specifies  the  amount of azimuthal pattern rotation
       (measured clockwise in degrees from True North) to  be  applied  by  SPLAT!  to  the  data
       contained  in  the  .az file.  This is followed by azimuth headings (0 to 360 degrees) and
       their associated normalized field patterns (0.000 to 1.000) separated by whitespace.

       The structure of SPLAT! elevation pattern files is slightly different.  The first line  of
       the  .el  file  specifies the amount of mechanical beam tilt applied to the antenna.  Note
       that a downward tilt (below the horizon) is expressed as a positive angle, while an upward
       tilt  (above  the horizon) is expressed as a negative angle.  This data is followed by the
       azimuthal direction of the tilt, separated by whitespace.

       The remainder of the file consists of elevation angles and their corresponding  normalized
       voltage  radiation  pattern  (0.000  to  1.000) values separated by whitespace.  Elevation
       angles must be specified over a -10.0 to +90.0 degree range.  As was the  convention  with
       mechanical  beamtilt, negative elevation angles are used to represent elevations above the
       horizon, while positive angles represents elevations below the horizon.

       For example, the first few lines a SPLAT! elevation pattern file might appear  as  follows
       (kvea.el):

               1.1    130.0
              -10.0   0.172
              -9.5    0.109
              -9.0    0.115
              -8.5    0.155
              -8.0    0.157
              -7.5    0.104
              -7.0    0.029
              -6.5    0.109
              -6.0    0.185

       In  this  example,  the  antenna  is  mechanically  tilted downward 1.1 degrees towards an
       azimuth of 130.0 degrees.

       For best results, the resolution of azimuth  pattern  data  should  be  specified  to  the
       nearest  degree  azimuth, and elevation pattern data resolution should be specified to the
       nearest 0.01 degrees.  If the  pattern  data  specified  does  not  reach  this  level  of
       resolution,  SPLAT!  will  interpolate  the  values  provided to determine the data at the
       required resolution, although this may result in a loss in accuracy.

EXPORTING AND IMPORTING REGIONAL CONTOUR DATA

       Performing a regional coverage analysis based on an ITM path analysis can be a  very  time
       consuming  process,  especially  if  the analysis is performed repeatedly to discover what
       effects changes to a  transmitter's  antenna  radiation  pattern  make  to  the  predicted
       coverage area.

       This  process  can  be  expedited  by  exporting the contour data produced by SPLAT! to an
       alphanumeric output (.ano) file.  The data contained in this file can then be modified  to
       incorporate  antenna  pattern  effects, and imported back into SPLAT! to quickly produce a
       revised contour map.  Depending on the way in which SPLAT! is invoked, alphanumeric output
       files can describe regional path loss, signal strength, or received signal power levels.

       For example, an alphanumeric output file containing path loss information can be generated
       by SPLAT! for a receive site 30 feet above ground level over a 50 mile radius  surrounding
       a  transmitter site to a maximum path loss of 140 dB (assuming ERP is not specified in the
       transmitter's .lrp file) using the following syntax:

       splat -t kvea -L 30.0 -R 50.0 -db 140 -ano pathloss.dat

       If ERP is specified in the .lrp file or on the command line through the -erp  switch,  the
       alphanumeric  output  file  will instead contain predicted field values in dBuV/m.  If the
       -dBm command line switch is used, then the alphanumeric output file will  contain  receive
       signal power levels in dBm.

       SPLAT!  alphanumeric  output  files  can  exceed many hundreds of megabytes in size.  They
       contain information relating to the boundaries of the region  they  describe  followed  by
       latitudes (degrees North), longitudes (degrees West), azimuths (referenced to True North),
       elevations (to the first obstruction), followed by either  path  loss  (in  dB),  received
       field  strength (in dBuV/m), or received signal power level (in dBm) without regard to the
       transmitting antenna's radiation pattern.

       The first few lines of a SPLAT! alphanumeric output  file  could  take  on  the  following
       appearance (pathloss.dat):

               119, 117    ; max_west, min_west
               35, 34      ; max_north, min_north
               34.2265424, 118.0631096, 48.199, -32.747, 67.70
               34.2270358, 118.0624421, 48.199, -19.161, 73.72
               34.2275292, 118.0617747, 48.199, -13.714, 77.24
               34.2280226, 118.0611072, 48.199, -10.508, 79.74
               34.2290094, 118.0597723, 48.199, -11.806, 83.26 *
               34.2295028, 118.0591048, 48.199, -11.806, 135.47 *
               34.2299962, 118.0584373, 48.199, -15.358, 137.06 *
               34.2304896, 118.0577698, 48.199, -15.358, 149.87 *
               34.2314763, 118.0564348, 48.199, -15.358, 154.16 *
               34.2319697, 118.0557673, 48.199, -11.806, 153.42 *
               34.2324631, 118.0550997, 48.199, -11.806, 137.63 *
               34.2329564, 118.0544322, 48.199, -11.806, 139.23 *
               34.2339432, 118.0530971, 48.199, -11.806, 139.75 *
               34.2344365, 118.0524295, 48.199, -11.806, 151.01 *
               34.2349299, 118.0517620, 48.199, -11.806, 147.71 *
               34.2354232, 118.0510944, 48.199, -15.358, 159.49 *
               34.2364099, 118.0497592, 48.199, -15.358, 151.67 *

       Comments  can  be  placed  in the file if they are preceeded by a semicolon.  The vim text
       editor has proven capable of editing files of this size.

       Note as was the case in the antenna pattern files,  negative  elevation  angles  refer  to
       upward  tilt  (above the horizon), while positive angles refer to downward tilt (below the
       horizon).  These angles refer to the elevation to the  receiving  antenna  at  the  height
       above  ground  level  specified  using  the  -L switch if the path between transmitter and
       receiver is unobstructed.  If the path between the transmitter and receiver is obstructed,
       an  asterisk  (*)  is  placed  on the end of the line, and the elevation angle returned by
       SPLAT! refers the elevation angle to the first  obstruction  rather  than  the  geographic
       location  specified  on the line.  This is done in response to the fact that the ITM model
       considers the energy reaching a distant point over an obstructed path to be the result  of
       the  energy  scattered over the top of the first obstruction along the path.  Since energy
       cannot reach  the  obstructed  location  directly,  the  actual  elevation  angle  to  the
       destination over such a path becomes irrelevant.

       When  modifying  SPLAT!  path  loss  files  to reflect antenna pattern data, only the last
       numeric column should be amended to reflect the antenna's normalized gain at  the  azimuth
       and  elevation  angles  specified in the file.  Programs and scripts capable of performing
       this task are left as an exercise for the user.

       Modified alphanumeric output files can  be  imported  back  into  SPLAT!   for  generating
       revised  coverage  maps  provided that the ERP and -dBm options are used as they were when
       the alphanumeric output file was originally generated:

       splat -t kvea -ani pathloss.dat -s city.dat -b county.dat -o map.ppm

       Note that alphanumeric output files generated by splat cannot be used  with  splat-hd,  or
       vice-versa  due to the resolution incompatibility between the two versions of the program.
       Also, each of the three types of alphanumeric  output  files  are  incompatible  with  one
       another,  so  a  file  containing path loss data cannot be imported into SPLAT! to produce
       signal strength or received power level contours, etc.

USER-DEFINED TERRAIN INPUT FILES

       A  user-defined  terrain  file  is  a  user-generated  text  file  containing   latitudes,
       longitudes,  and heights above ground level of specific terrain features believed to be of
       importance to the SPLAT! analysis being conducted, but  noticeably  absent  from  the  SDF
       files  being  used.   A user-defined terrain file is imported into a SPLAT! analysis using
       the -udt switch:

        splat -t tx_site -r rx_site -udt udt_file.txt -o map.ppm

       A user-defined terrain file has the following appearance and structure:

              40.32180556, 74.1325, 100.0 meters
              40.321805, 74.1315, 300.0
              40.3218055, 74.1305, 100.0 meters

       Terrain height is interpreted as  being  described  in  feet  above  ground  level  unless
       followed  by the word meters, and is added on top of the terrain specified in the SDF data
       for the locations specified.  Be aware that each user-defined  terrain  feature  specified
       will  be  interpreted as being 3-arc seconds in both latitude and longitude in splat and 1
       arc-second in latitude and longitude in splat-hd.  Features described in the  user-defined
       terrain file that overlap previously defined features in the file are ignored by SPLAT! to
       avoid ambiguity.

GROUND CLUTTER

       The height of ground clutter can be specified using the -gc switch:

             splat -t wnjt-dt -r kd2bd -gc 30.0 -H wnjt-dt_path.png

       The -gc switch as the effect of raising the overall terrain by  the  specified  amount  in
       feet  (or  meters if the -metric switch is invoked), except over areas at sea-level and at
       the transmitting and receiving antenna locations.

SIMPLE TOPOGRAPHIC MAP GENERATION

       In certain situations it may be desirable to  generate  a  topographic  map  of  a  region
       without  plotting  coverage areas, line-of-sight paths, or generating obstruction reports.
       There are several ways of doing this.   If  one  wishes  to  generate  a  topographic  map
       illustrating  the  location  of  a  transmitter  and receiver site along with a brief text
       report describing the locations and distances between the sites, the -n switch  should  be
       invoked as follows:

       splat -t tx_site -r rx_site -n -o topo_map.ppm

       If no text report is desired, then the -N switch is used:

       splat -t tx_site -r rx_site -N -o topo_map.ppm

       If  a  topographic  map  centered about a single site out to a minimum specified radius is
       desired instead, a command similar to the following can be used:

       splat -t tx_site -R 50.0 -s NJ_Cities -b NJ_Counties -o topo_map.ppm

       where -R specifies the minimum radius of the map in miles (or kilometers  if  the  -metric
       switch  is  used).   Note  that  the  tx_site  name and location are not displayed in this
       example.  If display of this information is desired, simply create a SPLAT! city file  (-s
       option) and append it to the list of command-line options illustrated above.

       If  the  -o switch and output filename are omitted in these operations, topographic output
       is written to a file named tx_site.ppm in the current working directory by default.

GEOREFERENCE FILE GENERATION

       Topographic, coverage (-c), and path loss contour (-L) maps generated  by  SPLAT!  may  be
       imported  into  Xastir  (X Amateur Station Tracking and Information Reporting) software by
       generating a georeference file using SPLAT!'s -geo switch:

       splat -t kd2bd -R 50.0 -s NJ_Cities -b NJ_Counties -geo -o map.ppm

       The georeference file generated will have the same base name as the -o file specified, but
       have  a   .geo  extension,  and  permit proper interpretation and display of SPLAT!'s .ppm
       graphics in Xastir software.

GOOGLE MAP KML FILE GENERATION

       Keyhole Markup Language files compatible with Google Earth may be generated by SPLAT! when
       performing point-to-point or regional coverage analyses by invoking the -kml switch:

       splat -t wnjt-dt -r kd2bd -kml

       The KML file generated will have the same filename structure as a Path Analysis Report for
       the transmitter and receiver site names given, except it will carry a  .kml extension.

       Once loaded into Google Earth (File --> Open), the KML file will annotate the map  display
       with the names of the transmitter and receiver site locations.  The viewpoint of the image
       will be from the position of the transmitter site looking  towards  the  location  of  the
       receiver.   The  point-to-point  path  between the sites will be displayed as a white line
       while the RF line-of-sight path will be displayed in  green.   Google  Earth's  navigation
       tools  allow  the  user  to  "fly"  around  the path, identify landmarks, roads, and other
       featured content.

       When performing regional coverage analysis, the  .kml file generated by SPLAT! will permit
       path loss or signal strength contours to be layered on top of Google Earth's display along
       with a corresponding color key in the upper left-hand corner.   The  generated  .kml  file
       will have the same basename as that of the .ppm file normally generated.

DETERMINATION OF ANTENNA HEIGHT ABOVE AVERAGE TERRAIN

       SPLAT!  determines  antenna height above average terrain (HAAT) according to the procedure
       defined  by  Federal  Communications  Commission  Part  73.313(d).   According   to   this
       definition,  terrain  elevations  along  eight  radials  between  2 and 10 miles (3 and 16
       kilometers) from the site being analyzed are sampled and averaged for each 45  degrees  of
       azimuth  starting with True North.  If one or more radials lie entirely over water or over
       land outside the United States (areas for which no USGS  topography  data  is  available),
       then those radials are omitted from the calculation of average terrain.

       Note that SRTM-3 elevation data, unlike older USGS data, extends beyond the borders of the
       United States.  Therefore, HAAT results may not  be  in  full  compliance  with  FCC  Part
       73.313(d)  in areas along the borders of the United States if the SDF files used by SPLAT!
       are SRTM-derived.

       When performing point-to-point terrain analysis,  SPLAT!  determines  the  antenna  height
       above  average  terrain  only  if  enough  topographic data has already been loaded by the
       program to perform the point-to-point analysis.  In most cases, this will be true,  unless
       the  site  in question does not lie within 10 miles of the boundary of the topography data
       in memory.

       When performing area prediction analysis, enough topography data  is  normally  loaded  by
       SPLAT!  to  perform  average  terrain  calculations.   Under  such conditions, SPLAT! will
       provide the antenna height above average terrain as well as the average terrain above mean
       sea level for azimuths of 0, 45, 90, 135, 180, 225, 270, and 315 degrees, and include such
       information in the generated site report.  If one or more of the  eight  radials  surveyed
       fall  over  water,  or  over regions for which no SDF data is available, SPLAT! reports No
       Terrain for the radial paths affected.

ADDITIONAL INFORMATION

       The latest news and  information  regarding  SPLAT!  software  is  available  through  the
       official SPLAT! software web page located at: http://www.qsl.net/kd2bd/splat.html.

AUTHORS

       John A. Magliacane, KD2BD <kd2bd@amsat.org>
              Creator, Lead Developer

       Doug McDonald <mcdonald@scs.uiuc.edu>
              Original Longley-Rice ITM Model integration

       Ron Bentley <ronbentley@embarqmail.com>
              Fresnel Zone plotting and clearance determination