1FGELEV(1)                    FlightGear man pages                    FGELEV(1)
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NAME

6       fgelev  -  Compute  FlightGear  scenery  elevation  for a given list of
7       points
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SYNOPSIS

10       fgelev   [--expire   num]   [--print-solidness]   [--fg-root   rootdir]
11       [--fg-scenery scenerydir]
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DESCRIPTION

14       fgelev is a standalone utility that, given a list of points on standard
15       input, prints the corresponding elevation for each of them on  standard
16       output.  It  can  also (optionally) print whether the material covering
17       that point is solid or not.
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19       The list of points must be in the following form:
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21           id lon lat
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23       where id is an arbitrary identifier for the point, lon is the longitude
24       of  the point and lat is the latitude of the point. Positive longitudes
25       (latitudes) correspond to points  located  in  the  Eastern  (Northern)
26       hemisphere;  negative  ones correspond to points located in the Western
27       (Southern) hemisphere.
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29       The list of elevations returned by fgelev is in the following form:
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31           id: elev solid
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33       where id is the identifier of the point passed as input,  elev  is  the
34       elevation  of  the  point  in  meters (or -1000 if the elevation of the
35       given point was not found) and solid is:
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37       ·  the string solid if the parameter --print-solidness  was  passed  to
38          fgelev and the material covering the point is solid;
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40       ·  the string - if the parameter --print-solidness was passed to fgelev
41          and the material covering the point is not solid;
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43       ·  absent if the parameter --print-solidness was not passed to fgelev.
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OPTIONS

46       --expire num
47              To speed up elevation data retrieval, fgelev  uses  an  internal
48              cache.  This option lets the user specify the number of requests
49              after which, if a point was not queried in them,  it  should  be
50              marked as expired. By default, fgelev expires points not queried
51              in the last 10 requests.
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53       --print-solidness
54              Require fgelev to print the solidness of the  material  covering
55              the queried point. See the DESCRIPTION section for more details.
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57       --fg-root rootdir
58              Set the FlightGear data root directory ($FG_ROOT) to rootdir. If
59              this option is not set, fgelev uses the path  specified  in  the
60              FG_ROOT  environment  variable  or,  absent that, the FlightGear
61              data directory chosen at the time the program was compiled.
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63       --fg-scenery scenerydir
64              Set the FlightGear scenery directory ($FG_SCENERY)  to  scenery‐
65              dir.   If this option is not set, fgelev uses the path specified
66              in the FG_SCENERY environment  variable  or,  absent  that,  the
67              Scenery subdirectory inside $FG_ROOT.
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EXIT STATUS

70       fgelev  exits  with EXIT_SUCCESS on success, with EXIT_FAILURE if it is
71       unable to read data from standard input or to load the scenery.
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ENVIRONMENT

74       FG_ROOT
75           If FG_ROOT is set and --fg-root is not set, it specifies  the  root
76           data directory to use.
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78       FG_SCENERY
79           If  FG_SCENERY is set and --fg-scenery is not set, it specifies the
80           scenery directory to use.
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SEE ALSO

83       fgfs(1)
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87FlightGear                        2017-06-04                         FGELEV(1)
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