SPLAT!(1) KD2BD Software SPLAT!(1) NNAAMMEE splat - A SSignal PPropagation, LLoss, AAnd TTerrain analysis tool SSYYNNOOPPSSIISS splat [-t _t_r_a_n_s_m_i_t_t_e_r___s_i_t_e_._q_t_h] [-r _r_e_c_e_i_v_e_r___s_i_t_e_._q_t_h] [-c _r_x___a_n_t_e_n_n_a___h_e_i_g_h_t___f_o_r___l_o_s___c_o_v_e_r_a_g_e___a_n_a_l_y_s_i_s _(_f_e_e_t_) _(_f_l_o_a_t_)] [-L _r_x___a_n_t_e_n_n_a___h_e_i_g_h_t___f_o_r___L_o_n_g_l_e_y_-_R_i_c_e___c_o_v_e_r_- _a_g_e___a_n_a_l_y_s_i_s _(_f_e_e_t_) _(_f_l_o_a_t_)] [-p _t_e_r_r_a_i_n___p_r_o_f_i_l_e_._e_x_t] [-e _e_l_e_v_a_t_i_o_n___p_r_o_f_i_l_e_._e_x_t] [-h _h_e_i_g_h_t___p_r_o_f_i_l_e_._e_x_t] [-l _L_o_n_g_- _l_e_y_-_R_i_c_e___p_r_o_f_i_l_e_._e_x_t] [-o _t_o_p_o_g_r_a_p_h_i_c___m_a_p___f_i_l_e_n_a_m_e_._p_p_m] [-b _c_a_r_t_o_g_r_a_p_h_i_c___b_o_u_n_d_a_r_y___f_i_l_e_n_a_m_e_._d_a_t] [-s _s_i_t_e_/_c_i_t_y___d_a_t_a_b_a_s_e_._d_a_t] [-d _s_d_f___d_i_r_e_c_t_o_r_y___p_a_t_h] [-m _e_a_r_t_h___r_a_d_i_u_s___m_u_l_t_i_p_l_i_e_r _(_f_l_o_a_t_)] [-R _m_a_x_i_m_u_m___c_o_v_e_r_- _a_g_e___r_a_n_g_e _(_f_o_r _-_c _o_r _-_L_) _(_m_i_l_e_s_) _(_f_l_o_a_t_)] [-n] [-N] DDEESSCCRRIIPPTTIIOONN SSPPLLAATT!! is a simple, yet powerful terrain analysis tool written for Unix and Linux-based workstations. SSPPLLAATT!! is free software. Redistribution and/or modification is per- mitted under the terms of the GNU General Public License as published by the Free Software Foundation, either ver- sion 2 of the License or any later version. Adoption of SSPPLLAATT!! source code in proprietary or closed-source appli- cations is a violation of this license, and is ssttrriiccttllyy forbidden. SSPPLLAATT!! is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY, without even the implied war- ranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PUR- POSE. See the GNU General Public License for more details. IINNTTRROODDUUCCTTIIOONN SSPPLLAATT!! is a terrestrial RF propagation analysis tool for the spectrum between 20 MHz and 20 GHz, and provides information of interest to communication system designers and site engineers. SSPPLLAATT!! determines great circle dis- tances and bearings between sites, antenna elevation angles (uptilt), depression angles (downtilt), antenna height above mean sea level, antenna height above average terrain, bearings and distances to known obstructions, Longley-Rice path loss, and minimum antenna height requirements needed to establish line-of-sight communica- tion paths absent of obstructions due to terrain. SSPPLLAATT!! produces reports, graphs, and highly detailed and care- fully annotated topographic maps depicting line-of-sight paths, path loss, and expected coverage areas of transmit- ters and repeater systems. When performing line-of-sight analysis in situations where multiple transmitter or repeater sites are employed, SSPPLLAATT!! determines individual and mutual areas of coverage within the network specified. SSPPLLAATT!! operates in two modes: _p_o_i_n_t_-_t_o_-_p_o_i_n_t _m_o_d_e, and _a_r_e_a _p_r_e_d_i_c_t_i_o_n _m_o_d_e. These modes may be invoked using either line-of-sight (LOS) or Irregular Terrain (ITM) propagation models. True Earth, four-thirds Earth, or any other Earth radius may be specified by the user when per- forming line-of-sight analysis. IINNPPUUTT FFIILLEESS SSPPLLAATT!! is a command-line driven application, and reads input data through a number of data files. Each has its own format. Some files are mandatory for successful exe- cution of the program, while others are optional. Manda- tory files include SPLAT Data Files (SDF files), site location files (QTH files), and Longley-Rice model parame- ter files (LRP files). Optional files include city/site location files, and cartographic boundary files. SSPPLLAATT DDAATTAA FFIILLEESS SSPPLLAATT!! imports topographic data in the form of SPLAT Data Files (SDFs) that may be generated from a number of infor- mation sources. In the United States, SPLAT Data Files are most often derived from U.S. Geological Survey Digi- tal Elevation Models (DEMs) using the uussggss22ssddff utility included with SSPPLLAATT!!. USGS Digital Elevation Models com- patible with this utility are available at no cost via the Internet at: _h_t_t_p_:_/_/_e_d_c_- _s_g_s_9_._c_r_._u_s_g_s_._g_o_v_/_g_l_i_s_/_h_y_p_e_r_/_g_u_i_d_e_/_1___d_g_r___d_e_m_- _f_i_g_/_i_n_d_e_x_1_m_._h_t_m_l. SPLAT Data Files contain topographic elevations to the nearest meter above mean sea level for 1-degree by 1-degree regions of the earth with a resolution of 3-arc seconds. SDF files can be read in either standard format (_._s_d_f) as generated by the uussggss22ssddff utility, or in bzip2 compressed format (_._s_d_f_._b_z_2). Since uncompressed files can be slightly faster to load than compressed files, SSPPLLAATT!! searches for the needed SDF data in uncompressed format first. If such data cannot located, then SSPPLLAATT!! tries to read the data in bzip2 compressed format. If no compressed SDF files can be found for the region requested, SSPPLLAATT!! assumes the region is over water or out- side the United States, and will assign an elevation of sea-level to these areas. This feature of SSPPLLAATT!! makes it possible to perform path analysis not only over land, but also between coastal areas not represented by USGS Digital Elevation Model Data since they are devoid of any land masses. However, this behavior of SSPPLLAATT!! underscores the importance of having all the SDF files required for the region being analyzed if meaningful results are to be expected. SSIITTEE LLOOCCAATTIIOONN ((QQTTHH)) FFIILLEESS SSPPLLAATT!! imports site location information of transmitter and receiver sites analyzed by the program from ASCII files having a _._q_t_h extension. QTH files contain the site's name, the site's latitude (in degrees North), the site's longitude (in degrees West), and the site's antenna height above ground level (AGL). A single line-feed char- acter separates each field. The antenna height is assumed to be specified in feet unless followed by the letter _m or the word _m_e_t_e_r_s in either upper or lower case. Latitude and longitude information may be expressed in either deci- mal format (74.6889) or degree, minute, second (DMS) for- mat (74 41 20.0). For example, a site location file describing television station WNJT, Trenton, NJ (_w_n_j_t_._q_t_h) might read as fol- lows: WNJT 40.2833 74.6889 990.00 Each transmitter and receiver site analyzed by SSPPLLAATT!! must be represented by its own site location (QTH) file. LLOONNGGLLEEYY--RRIICCEE PPAARRAAMMEETTEERR ((LLRRPP)) FFIILLEESS SSPPLLAATT!! imports Longley-Rice model parameter data from files having the same base name as the transmitter site QTH file, but carrying a _._l_r_p extension, thus providing simple and accurate correlation between these associated data sets. The format for the Longley-Rice model parame- ter files is as follows (_w_n_j_t_._l_r_p): 15.000 ; Earth Dielectric Constant (Relative per- mittivity) 0.005 ; Earth Conductivity (Siemens per meter) 301.000 ; Atmospheric Bending Constant (N-units) 700.000 ; Frequency in MHz (20 MHz to 20 GHz) 5 ; Radio Climate (5 = Continental Temper- ate) 0 ; Polarization (0 = Horizontal, 1 = Verti- cal) 0.5 ; Fraction of situations (50% of loca- tions) 0.5 ; Fraction of time (50% of the time) If an LRP file corresponding to the tx_site QTH file can- not be found, SSPPLLAATT!! scans the current working directory for the file "splat.lrp". If this file cannot be found, then the default parameters listed above will be assigned by SSPPLLAATT!! and a corresponding "splat.lrp" file containing this data will be written to the current working direc- tory. Typical Earth dielectric constants and conductivity values are as follows: Dielectric Constant Conductiv- ity 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 SSPPLLAATT!! 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 final two parameters in the _._l_r_p file correspond to the statistical analysis provided by the Longley-Rice model. In this example, SSPPLLAATT!! will return the maximum path loss occurring 50% of the time (fraction of time) in 50% of situations (fraction of situations). Use a fraction of time parameter of 0.97 for digital television, 0.50 for analog in the United States. Isotropic antennas are assumed. For further information on these parameters, see: _h_t_t_p_:_/_/_e_l_b_e_r_t_._i_t_s_._b_l_d_r_d_o_c_._g_o_v_/_i_t_m_._h_t_m_l and _h_t_t_p_:_/_/_w_w_w_._s_o_f_t_w_r_i_g_h_t_._c_o_m_/_f_a_q_/_e_n_g_i_n_e_e_r_i_n_g_/_p_r_o_p___l_o_n_g_- _l_e_y___r_i_c_e_._h_t_m_l CCIITTYY LLOOCCAATTIIOONN FFIILLEESS The names and locations of cities, tower sites, or other points of interest may imported and be plotted on topo- graphic maps generated by SSPPLLAATT!!. SSPPLLAATT!! imports the names of cities and locations from ASCII files containing the location's name, the location's latitude, and the location's longitude. Each field is separated by a comma. Each record is separated by a single line feed character. As was the case with the _._q_t_h files, latitude and longi- tude information may be entered in either decimal or degree, minute, second (DMS) format. For example (_c_i_t_i_e_s_._d_a_t): 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. There is no limit to the size of these files. SSPPLLAATT!! reads city data sequentially, and plots only those locations whose positions do not conflict with previously plotted locations when generating topographic maps. 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 cciittyyddee-- ccooddeerr utility included with SSPPLLAATT!!. Such data is avail- able free of charge via the Internet at: _h_t_t_p_:_/_/_w_w_w_._c_e_n_- _s_u_s_._g_o_v_/_g_e_o_/_w_w_w_/_c_o_b_/_b_d_y___f_i_l_e_s_._h_t_m_l, and must be in ASCII format. CCAARRTTOOGGRRAAPPHHIICC BBOOUUNNDDAARRYY DDAATTAA FFIILLEESS Cartographic boundary data may also be imported to plot the boundaries of cities, counties, or states on topo- graphic maps generated by SSPPLLAATT!!. 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: _h_t_t_p_:_/_/_w_w_w_._c_e_n_- _s_u_s_._g_o_v_/_g_e_o_/_w_w_w_/_c_o_b_/_c_o_2_0_0_0_._h_t_m_l_#_a_s_c_i_i and _h_t_t_p_:_/_/_w_w_w_._c_e_n_- _s_u_s_._g_o_v_/_g_e_o_/_w_w_w_/_c_o_b_/_p_l_2_0_0_0_._h_t_m_l_#_a_s_c_i_i. 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. PPRROOGGRRAAMM OOPPEERRAATTIIOONN SSPPLLAATT!! is invoked via the command-line using a series of switches and arguments. Since SSPPLLAATT!! is a CPU and memory intensive application, this type of interface minimizes overhead, and also lends itself well to scripted opera- tions. SSPPLLAATT!!'s CPU and memory scheduling priority may be adjusted through the use of the Unix nniiccee command. The number and type of switches passed to SSPPLLAATT!! determine its mode of operation and method of output data genera- tion. Nearly all of SSPPLLAATT!!'s switches may be cascaded in any order on the command line when invoking the program to include all the features described by those switches when performing an analysis. PPOOIINNTT--TTOO--PPOOIINNTT AANNAALLYYSSIISS SSPPLLAATT!! may be used to perform line-of-sight terrain analy- sis between two specified site locations. For example: splat -t tx_site.qth -r rx_site.qth invokes a terrain analysis between the transmitter speci- fied in _t_x___s_i_t_e_._q_t_h and receiver specified in _r_x___s_i_t_e_._q_t_h, and writes a SSPPLLAATT!! Obstruction Report to the current working directory. The report contains details of the transmitter and receiver sites, and identifies the loca- tion of any obstructions detected during the analysis. If an obstruction can be cleared by raising the receive antenna to a greater altitude, SSPPLLAATT!! will indicate the minimum antenna height required for a line-of-sight path to exist between the transmitter and receiver locations specified. If the antenna must be raised a significant amount, this determination may take some time. are optional when invoking the program. SSPPLLAATT!! automati- cally reads all SPLAT Data Files necessary to conduct the terrain analysis between the sites specified. By default, the location of SDF files is assumed to be in the current working directory unless a ".splat_path" file is present under the user's home directory. If this file is present, it must contain the full directory path to the location of all the SDF files required by SSPPLLAATT!! to perform its analy- sis for the region containing the transmitter and receiver sites specified. The path in this file must be of the form of a single line of ASCII text: /opt/splat/sdf/ and may be generated with any text editor. The default path specified in the _$_H_O_M_E_/_._s_p_l_a_t___p_a_t_h file may be over- ridden at any time using the _-_d switch: splat -t tx_site -r rx_site -d /cdrom/sdf/ 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.gif SSPPLLAATT!! invokes ggnnuupplloott when generating graphs. The file- name extension specified to SSPPLLAATT!! determines the format of the graph produced. _._g_i_f will produce a 640x480 color GIF graphic file, while _._p_s or _._p_o_s_t_s_c_r_i_p_t will produce postscript output. Output in formats such as PNG, Adobe Illustrator, AutoCAD dxf, LaTeX, and many others are available. Please consult ggnnuupplloott, and ggnnuupplloott's documen- tation 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.gif The graph produced using this switch illustrates the ele- vation 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 eleva- tion 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.gif The Earth's curvature is clearly evident when plotting height profiles. A graph showing Longley-Rice path loss may be plotted using the _-_l switch: splat -t tx_site -r rx_site -l path_loss_profile.gif When performing path loss profiles, a Longley-Rice Model Path Loss Report is generated by SSPPLLAATT!! in the form of a text file with a _._l_r_o filename extension. The report con- tains bearings and distances between the transmitter and receiver, as well as the Longley-Rice path loss for vari- ous distances between the transmitter and receiver loca- tions. The mode of propagation for points along the path are given as _L_i_n_e_-_o_f_-_S_i_g_h_t, _S_i_n_g_l_e _H_o_r_i_z_o_n, _D_o_u_b_l_e _H_o_r_i_- _z_o_n, _D_i_f_f_r_a_c_t_i_o_n _D_o_m_i_n_a_n_t, and _T_r_o_p_o_s_c_a_t_t_e_r _D_o_m_i_n_a_n_t. To determine the signal-to-noise (SNR) ratio at remote location where random Johnson (thermal) noise is the pri- mary limiting factor in reception: _S_N_R=_T-_N_J-_L+_G-_N_F where TT is the ERP of the transmitter in dBW, NNJJ is John- son Noise in dBW (-136 dBW for a 6 MHz TV channel), LL is the path loss provided by SSPPLLAATT!! in dB (as a _p_o_s_i_t_i_v_e num- ber), GG is the receive antenna gain in dB over isotropic, and NNFF is the receiver noise figure in dB. TT may be computed as follows: _T=_T_I+_G_T where TTII is actual amount of RF power delivered to the transmitting antenna in dBW, GGTT is the transmitting antenna gain (over isotropic) in the direction of the receiver (or the horizon if the receiver is over the hori- zon). To compute how much more signal is available over the min- imum to necessary to achieve a specific signal-to-noise ratio: _S_i_g_n_a_l__M_a_r_g_i_n=_S_N_R-_S where SS is the minimum desired SNR ratio (15.5 dB for ATSC DTV, 42 dB for analog NTSC television). A topographic map may be generated by SSPPLLAATT!! to visualize the path between the transmitter and receiver sites from yet another perspective. Topographic maps generated by SSPPLLAATT!! 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 in blue. SSPPLLAATT!! generated topographic maps are 24-bit TrueColor Portable PixMap (PPM) images, and may be viewed, edited, or converted to other graphic formats by popular image viewing applications such as xxvv, TThhee GGIIMMPP, IImmaaggeeMMaaggiicckk, and XXPPaaiinntt. PNG format is highly recommended for lossless compressed storage of SSPPLLAATT!! generated topographic output files. An excellent command-line utility capable of con- verting SSPPLLAATT!! PPM graphic files to PNG files is wwppnngg, and is available at: _h_t_t_p_:_/_/_w_w_w_._l_i_b_p_n_g_._o_r_g_/_p_u_b_/_p_n_g_/_b_o_o_k_/_s_o_u_r_c_e_s_._h_t_m_l. As a last resort, PPM files may be compressed using the bzip2 utility, and read directly by TThhee GGIIMMPP in this format. Topographic output is specified using the _-_o switch: splat -t tx_site -r rx_site -o topo_map.ppm The _._p_p_m extension on the output filename is assumed by SSPPLLAATT!!, and is optional. In this example, _t_o_p_o___m_a_p_._p_p_m will illustrate the loca- tions 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 _r_x___s_i_t_e_._q_t_h). 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 SSPPLLAATT!! 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 SSPPLLAATT!! 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 SSPPLLAATT!! at a time for analysis: splat -t tx_site1 tx_site2 tx_site3 tx_site4 -r rx_site -p profile.gif In this example, four separate terrain profiles and obstruction reports will be generated by SSPPLLAATT!!. 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. DDEETTEERRMMIINNIINNGG RREEGGIIOONNAALL CCOOVVEERRAAGGEE SSPPLLAATT!! can analyze a transmitter or repeater site, or net- work of sites, and predict the regional coverage for each site specified. In this mode, SSPPLLAATT!! can generate a topo- graphic map displaying the geometric line-of-sight cover- age 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. SSPPLLAATT!! switches from point-to- point analysis mode to area prediction mode when the _-_c switch is invoked as follows: splat -t tx_site -c 30.0 -s cities.dat -b co34_d00.dat -o tx_coverage In this example, SSPPLLAATT!! generates a topographic map called _t_x___c_o_v_e_r_a_g_e_._p_p_m that illustrates the predicted line-of- sight regional coverage of _t_x___s_i_t_e to receiving locations having antennas 30.0 feet above ground level (AGL). The contents of _c_i_t_i_e_s_._d_a_t are plotted on the map, as are the cartographic boundaries contained in the file _c_o_3_4___d_0_0_._d_a_t. When plotting line-of-sight paths and areas of regional coverage, SSPPLLAATT!! 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 -c 30.0 -m 1.333 -s cities.dat -b coun- ties.dat -o map.ppm An earth radius multiplier of 1.333 instructs SSPPLLAATT!! to use the "four-thirds earth" model for line-of-sight propa- gation analysis. Any appropriate earth radius multiplier may be selected by the user. When invoked in area prediction mode, SSPPLLAATT!! generates a site report for each station analyzed. SSPPLLAATT!! 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 in the directions of 0, 45, 90, 135, 180, 225, 270, and 315 degrees azimuth. If the _-_c switch is replaced by a _-_L switch, a Longley- Rice path loss map for a transmitter site may be gener- ated: splat -t tx_site -L 30.0 -s cities.dat -b co34_d00.dat -o path_loss_map In this mode, SSPPLLAATT!! generates a multi-color map illus- trating expected signal levels (path loss) in areas sur- rounding the transmitter site. A legend at the bottom of the map correlates each color with a specific path loss level in decibels. Since Longley-Rice area prediction map generation is quite CPU intensive, provision for limiting the analysis range is provided by the _-_R switch. The argument must be given in miles. If a range wider than the generated topographic map is specified, SSPPLLAATT!! will perform Longley-Rice path loss calculations between all four corners of the area prediction map. DDEETTEERRMMIINNIINNGG MMUULLTTIIPPLLEE RREEGGIIOONNSS OOFF CCOOVVEERRAAGGEE SSPPLLAATT!! 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 30.0 -o network.ppm plots the regional line-of-sight coverage of site1, site2, site3, and site4 based on a receive antenna located 30.0 feet above ground level. A topographic map is then writ- ten to the file _n_e_t_w_o_r_k_._p_p_m. The line-of-sight coverage area of the transmitters are plotted as follows in the colors indicated (along with their corresponding RGB val- ues 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 _._q_t_h 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 SSPPLLAATT!!. TTOOPPOOGGRRAAPPHHIICC MMAAPP GGEENNEERRAATTIIOONN 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 fol- lows: 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 the _-_o switch and output filename are omitted when using either the _-_n or _-_N switches, output is written to a file named _m_a_p_._p_p_m in the current working directory by default. DDEETTEERRMMIINNAATTIIOONN OOFF AANNTTEENNNNAA HHEEIIGGHHTT AABBOOVVEE AAVVEERRAAGGEE TTEERRRRAAIINN SSPPLLAATT!! determines antenna height above average terrain (HAAT) according to the procedure defined by Federal Com- munications 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 avail- able), then those radials are omitted from the calculation of average terrain. If part of a radial extends over a body of water or over land outside the United States, then only that part of the radial lying over United States land is used in the determination of average terrain. When performing point-to-point terrain analysis, SSPPLLAATT!! 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 topogra- phy data is normally loaded by SSPPLLAATT!! to perform average terrain calculations. Under such conditions, SSPPLLAATT!! 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 site report generated. If one or more of the eight radials surveyed fall over water or land outside the United States, SSPPLLAATT!! reports _N_o _T_e_r_- _r_a_i_n for those radial paths. SSEETTTTIINNGG TTHHEE MMAAXXIIMMUUMM SSIIZZEE OOFF AANN AANNAALLYYSSIISS RREEGGIIOONN SSPPLLAATT!! reads SDF files into a series of memory "slots" as required within the structure of the program. Each "slot" holds one SDF file. Each SDF file represents a one degree by one degree region of terrain. A _#_d_e_f_i_n_e _M_A_X_S_L_O_T_S statement in the first several lines of _s_p_l_a_t_._c_p_p sets the maximum number of "slots" available for topography data. It also sets the maximum size of the topographic maps gen- erated by SSPPLLAATT!!. MAXSLOTS is set to 9 by default. If SSPPLLAATT!! produces a segmentation fault on start-up with this default, it is an indication that not enough RAM and/or virtual memory (swap space) are available to run SSPPLLAATT!! with this number of MAXSLOTS. In this case, MAXSLOTS may be reduced to 4, although this will greatly limit the max- imum region SSPPLLAATT!! will be able to analyze. If 118 megabytes or more of total memory (swap space plus RAM) is available, then MAXSLOTS may be increased to 16. This will permit operation over a 4-degree by 4-degree region, which is sufficient for single antenna heights in excess of 10,000 feet above mean sea level, or point-to-point distances of over 1000 miles. AADDDDIITTIIOONNAALL IINNFFOORRMMAATTIIOONN Invoking SSPPLLAATT!! without any arguments will display all the command-line options available with the program along with a brief summary of each. The latest news and information regarding SSPPLLAATT!! software is available through the official SSPPLLAATT!! software web page located at: _h_t_t_p_:_/_/_w_w_w_._q_s_l_._n_e_t_/_k_d_2_b_d_/_s_p_l_a_t_._h_t_m_l. FFIILLEESS $HOME/.splat_path User-generated file containing the default path to the directory containing the SDF data files. splat.lrp Default Longley-Rice model parameters. AAUUTTHHOORRSS John A. Magliacane, KD2BD <_k_d_2_b_d_@_a_m_s_a_t_._o_r_g> Creator, Lead Developer Doug McDonald <_m_c_d_o_n_a_l_d_@_s_c_s_._u_i_u_c_._e_d_u> Longley-Rice Model integration KD2BD Software 20 January 2004 SPLAT!(1)