1 SPLAT!(1) KD2BD Software SPLAT!(1)
6 splat - A Signal Propagation, Loss, And Terrain analysis
10 splat [-t transmitter_site.qth] [-r receiver_site.qth] [-c
11 rx_antenna_height_for_los_coverage_analysis (feet)
12 (float)] [-L rx_antenna_height_for_Longley-Rice_cover-
13 age_analysis (feet) (float)] [-p terrain_profile.ext] [-e
14 elevation_profile.ext] [-h height_profile.ext] [-l Long-
15 ley-Rice_profile.ext] [-o topographic_map_filename.ppm]
16 [-b cartographic_boundary_filename.dat] [-s
17 site/city_database.dat] [-d sdf_directory_path] [-m
18 earth_radius_multiplier (float)] [-R maximum_cover-
19 age_range (for -c or -L) (miles) (float)] [-n] [-N]
22 SPLAT! is a simple, yet powerful terrain analysis tool
23 written for Unix and Linux-based workstations. SPLAT! is
24 free software. Redistribution and/or modification is per-
25 mitted under the terms of the GNU General Public License
26 as published by the Free Software Foundation, either ver-
27 sion 2 of the License or any later version. Adoption of
28 SPLAT! source code in proprietary or closed-source appli-
29 cations is a violation of this license, and is strictly
32 SPLAT! is distributed in the hope that it will be useful,
33 but WITHOUT ANY WARRANTY, without even the implied war-
34 ranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PUR-
35 POSE. See the GNU General Public License for more details.
38 SPLAT! is a terrestrial RF propagation analysis tool for
39 the spectrum between 20 MHz and 20 GHz, and provides
40 information of interest to communication system designers
41 and site engineers. SPLAT! determines great circle dis-
42 tances and bearings between sites, antenna elevation
43 angles (uptilt), depression angles (downtilt), antenna
44 height above mean sea level, antenna height above average
45 terrain, bearings and distances to known obstructions,
46 Longley-Rice path loss, and minimum antenna height
47 requirements needed to establish line-of-sight communica-
48 tion paths absent of obstructions due to terrain. SPLAT!
49 produces reports, graphs, and highly detailed and care-
50 fully annotated topographic maps depicting line-of-sight
51 paths, path loss, and expected coverage areas of transmit-
52 ters and repeater systems. When performing line-of-sight
53 analysis in situations where multiple transmitter or
54 repeater sites are employed, SPLAT! determines individual
55 and mutual areas of coverage within the network specified.
57 SPLAT! operates in two modes: point-to-point mode, and
58 area prediction mode. These modes may be invoked using
59 either line-of-sight (LOS) or Irregular Terrain (ITM)
60 propagation models. True Earth, four-thirds Earth, or any
61 other Earth radius may be specified by the user when per-
62 forming line-of-sight analysis.
65 SPLAT! is a command-line driven application, and reads
66 input data through a number of data files. Each has its
67 own format. Some files are mandatory for successful exe-
68 cution of the program, while others are optional. Manda-
69 tory files include SPLAT Data Files (SDF files), site
70 location files (QTH files), and Longley-Rice model parame-
71 ter files (LRP files). Optional files include city/site
72 location files, and cartographic boundary files.
75 SPLAT! imports topographic data in the form of SPLAT Data
76 Files (SDFs) that may be generated from a number of infor-
77 mation sources. In the United States, SPLAT Data Files
78 are most often derived from U.S. Geological Survey Digi-
79 tal Elevation Models (DEMs) using the usgs2sdf utility
80 included with SPLAT!. USGS Digital Elevation Models com-
81 patible with this utility are available at no cost via the
82 Internet at: http://edc-
83 sgs9.cr.usgs.gov/glis/hyper/guide/1_dgr_dem-
86 SPLAT Data Files contain topographic elevations to the
87 nearest meter above mean sea level for 1-degree by
88 1-degree regions of the earth with a resolution of 3-arc
89 seconds. SDF files can be read in either standard format
90 (.sdf) as generated by the usgs2sdf utility, or in bzip2
91 compressed format (.sdf.bz2). Since uncompressed files
92 can be slightly faster to load than compressed files,
93 SPLAT! searches for the needed SDF data in uncompressed
94 format first. If such data cannot located, then SPLAT!
95 tries to read the data in bzip2 compressed format. If no
96 compressed SDF files can be found for the region
97 requested, SPLAT! assumes the region is over water or out-
98 side the United States, and will assign an elevation of
99 sea-level to these areas. This feature of SPLAT! makes it
100 possible to perform path analysis not only over land, but
101 also between coastal areas not represented by USGS Digital
102 Elevation Model Data since they are devoid of any land
103 masses. However, this behavior of SPLAT! underscores the
104 importance of having all the SDF files required for the
105 region being analyzed if meaningful results are to be
108 SITE LOCATION (QTH) FILES
109 SPLAT! imports site location information of transmitter
110 and receiver sites analyzed by the program from ASCII
111 files having a .qth extension. QTH files contain the
112 site's name, the site's latitude (in degrees North), the
113 site's longitude (in degrees West), and the site's antenna
114 height above ground level (AGL). A single line-feed char-
115 acter separates each field. The antenna height is assumed
116 to be specified in feet unless followed by the letter m or
117 the word meters in either upper or lower case. Latitude
118 and longitude information may be expressed in either deci-
119 mal format (74.6889) or degree, minute, second (DMS) for-
122 For example, a site location file describing television
123 station WNJT, Trenton, NJ (wnjt.qth) might read as fol-
131 Each transmitter and receiver site analyzed by SPLAT! must
132 be represented by its own site location (QTH) file.
134 LONGLEY-RICE PARAMETER (LRP) FILES
135 SPLAT! imports Longley-Rice model parameter data from
136 files having the same base name as the transmitter site
137 QTH file, but carrying a .lrp extension, thus providing
138 simple and accurate correlation between these associated
139 data sets. The format for the Longley-Rice model parame-
140 ter files is as follows (wnjt.lrp):
142 15.000 ; Earth Dielectric Constant (Relative per-
144 0.005 ; Earth Conductivity (Siemens per meter)
145 301.000 ; Atmospheric Bending Constant (N-units)
146 700.000 ; Frequency in MHz (20 MHz to 20 GHz)
147 5 ; Radio Climate (5 = Continental Temper-
149 0 ; Polarization (0 = Horizontal, 1 = Verti-
151 0.5 ; Fraction of situations (50% of loca-
153 0.5 ; Fraction of time (50% of the time)
155 If an LRP file corresponding to the tx_site QTH file can-
156 not be found, SPLAT! scans the current working directory
157 for the file "splat.lrp". If this file cannot be found,
158 then the default parameters listed above will be assigned
159 by SPLAT! and a corresponding "splat.lrp" file containing
160 this data will be written to the current working direc-
163 Typical Earth dielectric constants and conductivity values
166 Dielectric Constant Conductiv-
168 Salt water : 80 5.000
169 Good ground : 25 0.020
170 Fresh water : 80 0.010
171 Marshy land : 12 0.007
172 Farmland, forest : 15 0.005
173 Average ground : 15 0.005
174 Mountain, sand : 13 0.002
176 Poor ground : 4 0.001
178 Radio climate codes used by SPLAT! are as follows:
180 1: Equatorial (Congo)
181 2: Continental Subtropical (Sudan)
182 3: Maritime Subtropical (West coast of Africa)
184 5: Continental Temperate
185 6: Maritime Temperate, over land (UK and west
187 7: Maritime Temperate, over sea
189 The Continental Temperate climate is common to large land
190 masses in the temperate zone, such as the United States.
191 For paths shorter than 100 km, there is little difference
192 between Continental and Maritime Temperate climates.
194 The final two parameters in the .lrp file correspond to
195 the statistical analysis provided by the Longley-Rice
196 model. In this example, SPLAT! will return the maximum
197 path loss occurring 50% of the time (fraction of time) in
198 50% of situations (fraction of situations). Use a
199 fraction of time parameter of 0.97 for digital television,
200 0.50 for analog in the United States. Isotropic antennas
203 For further information on these parameters, see:
204 http://elbert.its.bldrdoc.gov/itm.html and
205 http://www.softwright.com/faq/engineering/prop_long-
209 The names and locations of cities, tower sites, or other
210 points of interest may imported and be plotted on topo-
211 graphic maps generated by SPLAT!. SPLAT! imports the
212 names of cities and locations from ASCII files containing
213 the location's name, the location's latitude, and the
214 location's longitude. Each field is separated by a comma.
215 Each record is separated by a single line feed character.
216 As was the case with the .qth files, latitude and longi-
217 tude information may be entered in either decimal or
218 degree, minute, second (DMS) format.
220 For example (cities.dat):
222 Teaneck, 40.891973, 74.014506
223 Tenafly, 40.919212, 73.955892
224 Teterboro, 40.859511, 74.058908
225 Tinton Falls, 40.279966, 74.093924
226 Toms River, 39.977777, 74.183580
227 Totowa, 40.906160, 74.223310
228 Trenton, 40.219922, 74.754665
230 A total of five separate city data files may be imported
231 at a time. There is no limit to the size of these files.
232 SPLAT! reads city data sequentially, and plots only those
233 locations whose positions do not conflict with previously
234 plotted locations when generating topographic maps.
236 City data files may be generated manually using any text
237 editor, imported from other sources, or derived from data
238 available from the U.S. Census Bureau using the cityde-
239 coder utility included with SPLAT!. Such data is avail-
240 able free of charge via the Internet at: http://www.cen-
241 sus.gov/geo/www/cob/bdy_files.html, and must be in ASCII
244 CARTOGRAPHIC BOUNDARY DATA FILES
245 Cartographic boundary data may also be imported to plot
246 the boundaries of cities, counties, or states on topo-
247 graphic maps generated by SPLAT!. Such data must be of
248 the form of ARC/INFO Ungenerate (ASCII Format) Metadata
249 Cartographic Boundary Files, and are available from the
250 U.S. Census Bureau via the Internet at: http://www.cen-
251 sus.gov/geo/www/cob/co2000.html#ascii and http://www.cen-
252 sus.gov/geo/www/cob/pl2000.html#ascii. A total of five
253 separate cartographic boundary files may be imported at a
254 time. It is not necessary to import state boundaries if
255 county boundaries have already been imported.
258 SPLAT! is invoked via the command-line using a series of
259 switches and arguments. Since SPLAT! is a CPU and memory
260 intensive application, this type of interface minimizes
261 overhead, and also lends itself well to scripted opera-
262 tions. SPLAT!'s CPU and memory scheduling priority may be
263 adjusted through the use of the Unix nice command.
265 The number and type of switches passed to SPLAT! determine
266 its mode of operation and method of output data genera-
267 tion. Nearly all of SPLAT!'s switches may be cascaded in
268 any order on the command line when invoking the program to
269 include all the features described by those switches when
270 performing an analysis.
272 POINT-TO-POINT ANALYSIS
273 SPLAT! may be used to perform line-of-sight terrain analy-
274 sis between two specified site locations. For example:
276 splat -t tx_site.qth -r rx_site.qth
278 invokes a terrain analysis between the transmitter speci-
279 fied in tx_site.qth and receiver specified in rx_site.qth,
280 and writes a SPLAT! Obstruction Report to the current
281 working directory. The report contains details of the
282 transmitter and receiver sites, and identifies the loca-
283 tion of any obstructions detected during the analysis. If
284 an obstruction can be cleared by raising the receive
285 antenna to a greater altitude, SPLAT! will indicate the
286 minimum antenna height required for a line-of-sight path
287 to exist between the transmitter and receiver locations
288 specified. If the antenna must be raised a significant
289 amount, this determination may take some time.
291 are optional when invoking the program. SPLAT! automati-
292 cally reads all SPLAT Data Files necessary to conduct the
293 terrain analysis between the sites specified. By default,
294 the location of SDF files is assumed to be in the current
295 working directory unless a ".splat_path" file is present
296 under the user's home directory. If this file is present,
297 it must contain the full directory path to the location of
298 all the SDF files required by SPLAT! to perform its analy-
299 sis for the region containing the transmitter and receiver
300 sites specified. The path in this file must be of the
301 form of a single line of ASCII text:
305 and may be generated with any text editor. The default
306 path specified in the $HOME/.splat_path file may be over-
307 ridden at any time using the -d switch:
309 splat -t tx_site -r rx_site -d /cdrom/sdf/
311 A graph of the terrain profile between the receiver and
312 transmitter locations as a function of distance from the
313 receiver can be generated by adding the -p switch:
315 splat -t tx_site -r rx_site -p terrain_profile.gif
317 SPLAT! invokes gnuplot when generating graphs. The file-
318 name extension specified to SPLAT! determines the format
319 of the graph produced. .gif will produce a 640x480 color
320 GIF graphic file, while .ps or .postscript will produce
321 postscript output. Output in formats such as PNG, Adobe
322 Illustrator, AutoCAD dxf, LaTeX, and many others are
323 available. Please consult gnuplot, and gnuplot's documen-
324 tation for details on all the supported output formats.
326 A graph of elevations subtended by the terrain between the
327 receiver and transmitter as a function of distance from
328 the receiver can be generated by using the -e switch:
330 splat -t tx_site -r rx_site -e elevation_profile.gif
332 The graph produced using this switch illustrates the ele-
333 vation and depression angles resulting from the terrain
334 between the receiver's location and the transmitter site
335 from the perspective of the receiver's location. A second
336 trace is plotted between the left side of the graph
337 (receiver's location) and the location of the transmitting
338 antenna on the right. This trace illustrates the eleva-
339 tion angle required for a line-of-sight path to exist
340 between the receiver and transmitter locations. If the
341 trace intersects the elevation profile at any point on the
342 graph, then this is an indication that a line-of-sight
343 path does not exist under the conditions given, and the
344 obstructions can be clearly identified on the graph at the
345 point(s) of intersection.
347 A graph illustrating terrain height referenced to a line-
348 of-sight path between the transmitter and receiver may be
349 generated using the -h switch:
351 splat -t tx_site -r rx_site -h height_profile.gif
353 The Earth's curvature is clearly evident when plotting
356 A graph showing Longley-Rice path loss may be plotted
359 splat -t tx_site -r rx_site -l path_loss_profile.gif
361 When performing path loss profiles, a Longley-Rice Model
362 Path Loss Report is generated by SPLAT! in the form of a
363 text file with a .lro filename extension. The report con-
364 tains bearings and distances between the transmitter and
365 receiver, as well as the Longley-Rice path loss for vari-
366 ous distances between the transmitter and receiver loca-
367 tions. The mode of propagation for points along the path
368 are given as Line-of-Sight, Single Horizon, Double Hori-
369 zon, Diffraction Dominant, and Troposcatter Dominant.
371 To determine the signal-to-noise (SNR) ratio at remote
372 location where random Johnson (thermal) noise is the pri-
373 mary limiting factor in reception:
377 where T is the ERP of the transmitter in dBW, NJ is John-
378 son Noise in dBW (-136 dBW for a 6 MHz TV channel), L is
379 the path loss provided by SPLAT! in dB (as a positive num-
380 ber), G is the receive antenna gain in dB over isotropic,
381 and NF is the receiver noise figure in dB.
383 T may be computed as follows:
387 where TI is actual amount of RF power delivered to the
388 transmitting antenna in dBW, GT is the transmitting
389 antenna gain (over isotropic) in the direction of the
390 receiver (or the horizon if the receiver is over the hori-
393 To compute how much more signal is available over the min-
394 imum to necessary to achieve a specific signal-to-noise
399 where S is the minimum desired SNR ratio (15.5 dB for ATSC
400 DTV, 42 dB for analog NTSC television).
402 A topographic map may be generated by SPLAT! to visualize
403 the path between the transmitter and receiver sites from
404 yet another perspective. Topographic maps generated by
405 SPLAT! display elevations using a logarithmic grayscale,
406 with higher elevations represented through brighter shades
407 of gray. The dynamic range of the image is scaled between
408 the highest and lowest elevations present in the map. The
409 only exception to this is sea-level, which is represented
412 SPLAT! generated topographic maps are 24-bit TrueColor
413 Portable PixMap (PPM) images, and may be viewed, edited,
414 or converted to other graphic formats by popular image
415 viewing applications such as xv, The GIMP, ImageMagick,
416 and XPaint. PNG format is highly recommended for lossless
417 compressed storage of SPLAT! generated topographic output
418 files. An excellent command-line utility capable of con-
419 verting SPLAT! PPM graphic files to PNG files is wpng, and
421 http://www.libpng.org/pub/png/book/sources.html. As a
422 last resort, PPM files may be compressed using the bzip2
423 utility, and read directly by The GIMP in this format.
424 Topographic output is specified using the -o switch:
426 splat -t tx_site -r rx_site -o topo_map.ppm
428 The .ppm extension on the output filename is assumed by
429 SPLAT!, and is optional.
431 In this example, topo_map.ppm will illustrate the loca-
432 tions of the transmitter and receiver sites specified. In
433 addition, the great circle path between the two sites will
434 be drawn over locations for which an unobstructed path
435 exists to the transmitter at a receiving antenna height
436 equal to that of the receiver site (specified in
439 It may desirable to populate the topographic map with
440 names and locations of cities, tower sites, or other
441 important locations. A city file may be passed to SPLAT!
444 splat -t tx_site -r rx_site -s cities.dat -o topo_map
446 Up to five separate city files may be passed to SPLAT! at
447 a time following the -s switch.
449 County and state boundaries may be added to the map by
450 specifying up to five U.S. Census Bureau cartographic
451 boundary files using the -b switch:
453 splat -t tx_site -r rx_site -b co34_d00.dat -o topo_map
455 In situations where multiple transmitter sites are in use,
456 as many as four site locations may be passed to SPLAT! at
459 splat -t tx_site1 tx_site2 tx_site3 tx_site4 -r rx_site -p
462 In this example, four separate terrain profiles and
463 obstruction reports will be generated by SPLAT!. A single
464 topographic map can be specified using the -o switch, and
465 line-of-sight paths between each transmitter and the
466 receiver site indicated will be produced on the map, each
467 in its own color. The path between the first transmitter
468 specified to the receiver will be in green, the path
469 between the second transmitter and the receiver will be in
470 cyan, the path between the third transmitter and the
471 receiver will be in violet, and the path between the
472 fourth transmitter and the receiver will be in sienna.
474 DETERMINING REGIONAL COVERAGE
475 SPLAT! can analyze a transmitter or repeater site, or net-
476 work of sites, and predict the regional coverage for each
477 site specified. In this mode, SPLAT! can generate a topo-
478 graphic map displaying the geometric line-of-sight cover-
479 age area of the sites based on the location of each site,
480 and the height of receive antenna wishing to communicate
481 with the site in question. SPLAT! switches from point-to-
482 point analysis mode to area prediction mode when the -c
483 switch is invoked as follows:
485 splat -t tx_site -c 30.0 -s cities.dat -b co34_d00.dat -o
488 In this example, SPLAT! generates a topographic map called
489 tx_coverage.ppm that illustrates the predicted line-of-
490 sight regional coverage of tx_site to receiving locations
491 having antennas 30.0 feet above ground level (AGL). The
492 contents of cities.dat are plotted on the map, as are the
493 cartographic boundaries contained in the file
496 When plotting line-of-sight paths and areas of regional
497 coverage, SPLAT! by default does not account for the
498 effects of atmospheric bending. However, this behavior
499 may be modified by using the Earth radius multiplier (-m)
502 splat -t wnjt -c 30.0 -m 1.333 -s cities.dat -b coun-
505 An earth radius multiplier of 1.333 instructs SPLAT! to
506 use the "four-thirds earth" model for line-of-sight propa-
507 gation analysis. Any appropriate earth radius multiplier
508 may be selected by the user.
510 When invoked in area prediction mode, SPLAT! generates a
511 site report for each station analyzed. SPLAT! site
512 reports contain details of the site's geographic location,
513 its height above mean sea level, the antenna's height
514 above mean sea level, the antenna's height above average
515 terrain, and the height of the average terrain calculated
516 in the directions of 0, 45, 90, 135, 180, 225, 270, and
519 If the -c switch is replaced by a -L switch, a Longley-
520 Rice path loss map for a transmitter site may be gener-
523 splat -t tx_site -L 30.0 -s cities.dat -b co34_d00.dat -o
526 In this mode, SPLAT! generates a multi-color map illus-
527 trating expected signal levels (path loss) in areas sur-
528 rounding the transmitter site. A legend at the bottom of
529 the map correlates each color with a specific path loss
530 level in decibels. Since Longley-Rice area prediction map
531 generation is quite CPU intensive, provision for limiting
532 the analysis range is provided by the -R switch. The
533 argument must be given in miles. If a range wider than
534 the generated topographic map is specified, SPLAT! will
535 perform Longley-Rice path loss calculations between all
536 four corners of the area prediction map.
538 DETERMINING MULTIPLE REGIONS OF COVERAGE
539 SPLAT! can also display line-of-sight coverage areas for
540 as many as four separate transmitter sites on a common
541 topographic map. For example:
543 splat -t site1 site2 site3 site4 -c 30.0 -o network.ppm
545 plots the regional line-of-sight coverage of site1, site2,
546 site3, and site4 based on a receive antenna located 30.0
547 feet above ground level. A topographic map is then writ-
548 ten to the file network.ppm. The line-of-sight coverage
549 area of the transmitters are plotted as follows in the
550 colors indicated (along with their corresponding RGB val-
553 site1: Green (0,255,0)
554 site2: Cyan (0,255,255)
555 site3: Medium Violet (147,112,219)
556 site4: Sienna 1 (255,130,71)
558 site1 + site2: Yellow (255,255,0)
559 site1 + site3: Pink (255,192,203)
560 site1 + site4: Green Yellow (173,255,47)
561 site2 + site3: Orange (255,165,0)
562 site2 + site4: Dark Sea Green 1 (193,255,193)
563 site3 + site4: Dark Turquoise (0,206,209)
565 site1 + site2 + site3: Dark Green (0,100,0)
566 site1 + site2 + site4: Blanched Almond (255,235,205)
567 site1 + site3 + site4: Medium Spring Green (0,250,154)
568 site2 + site3 + site4: Tan (210,180,140)
570 site1 + site2 + site3 + site4: Gold2 (238,201,0)
572 If separate .qth files are generated, each representing a
573 common site location but a different antenna height, a
574 single topographic map illustrating the regional coverage
575 from as many as four separate locations on a single tower
576 may be generated by SPLAT!.
578 TOPOGRAPHIC MAP GENERATION
579 In certain situations, it may be desirable to generate a
580 topographic map of a region without plotting coverage
581 areas, line-of-sight paths, or generating obstruction
582 reports. There are several ways of doing this. If one
583 wishes to generate a topographic map illustrating the
584 location of a transmitter and receiver site along with a
585 brief text report describing the locations and distances
586 between the sites, the -n switch should be invoked as fol-
589 splat -t tx_site -r rx_site -n -o topo_map.ppm
591 If no text report is desired, then the -N switch is used:
593 splat -t tx_site -r rx_site -N -o topo_map.ppm
595 If the -o switch and output filename are omitted when
596 using either the -n or -N switches, output is written to a
597 file named map.ppm in the current working directory by
600 DETERMINATION OF ANTENNA HEIGHT ABOVE AVERAGE TERRAIN
601 SPLAT! determines antenna height above average terrain
602 (HAAT) according to the procedure defined by Federal Com-
603 munications Commission Part 73.313(d). According to this
604 definition, terrain elevations along eight radials between
605 2 and 10 miles (3 and 16 kilometers) from the site being
606 analyzed are sampled and averaged for each 45 degrees of
607 azimuth starting with True North. If one or more radials
608 lie entirely over water, or over land outside the United
609 States (areas for which no USGS topography data is avail-
610 able), then those radials are omitted from the calculation
611 of average terrain. If part of a radial extends over a
612 body of water or over land outside the United States, then
613 only that part of the radial lying over United States land
614 is used in the determination of average terrain.
616 When performing point-to-point terrain analysis, SPLAT!
617 determines the antenna height above average terrain only
618 if enough topographic data has already been loaded by the
619 program to perform the point-to-point analysis. In most
620 cases, this will be true, unless the site in question does
621 not lie within 10 miles of the boundary of the topography
624 When performing area prediction analysis, enough topogra-
625 phy data is normally loaded by SPLAT! to perform average
626 terrain calculations. Under such conditions, SPLAT! will
627 provide the antenna height above average terrain as well
628 as the average terrain above mean sea level for azimuths
629 of 0, 45, 90, 135, 180, 225, 270, and 315 degrees, and
630 include such information in the site report generated. If
631 one or more of the eight radials surveyed fall over water
632 or land outside the United States, SPLAT! reports No Ter-
633 rain for those radial paths.
635 SETTING THE MAXIMUM SIZE OF AN ANALYSIS REGION
636 SPLAT! reads SDF files into a series of memory "slots" as
637 required within the structure of the program. Each "slot"
638 holds one SDF file. Each SDF file represents a one degree
639 by one degree region of terrain. A #define MAXSLOTS
640 statement in the first several lines of splat.cpp sets the
641 maximum number of "slots" available for topography data.
642 It also sets the maximum size of the topographic maps gen-
643 erated by SPLAT!. MAXSLOTS is set to 9 by default. If
644 SPLAT! produces a segmentation fault on start-up with this
645 default, it is an indication that not enough RAM and/or
646 virtual memory (swap space) are available to run SPLAT!
647 with this number of MAXSLOTS. In this case, MAXSLOTS may
648 be reduced to 4, although this will greatly limit the max-
649 imum region SPLAT! will be able to analyze. If 118
650 megabytes or more of total memory (swap space plus RAM) is
651 available, then MAXSLOTS may be increased to 16. This
652 will permit operation over a 4-degree by 4-degree region,
653 which is sufficient for single antenna heights in excess
654 of 10,000 feet above mean sea level, or point-to-point
655 distances of over 1000 miles.
657 ADDITIONAL INFORMATION
658 Invoking SPLAT! without any arguments will display all the
659 command-line options available with the program along with
660 a brief summary of each.
662 The latest news and information regarding SPLAT! software
663 is available through the official SPLAT! software web page
664 located at: http://www.qsl.net/kd2bd/splat.html.
668 User-generated file containing the default path to
669 the directory containing the SDF data files.
672 Default Longley-Rice model parameters.
675 John A. Magliacane, KD2BD <kd2bd@amsat.org>
676 Creator, Lead Developer
678 Doug McDonald <mcdonald@scs.uiuc.edu>
679 Longley-Rice Model integration
683 KD2BD Software 20 January 2004 SPLAT!(1)
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