The geopicts Command

The geopicts Command

The geopicts command geo-references files (e.g., picture files from a digital camera) either based on their time-stamps and a given track, or by using the sequence of waypoints in a group. The result is a file with waypoints (at present in GPX format) that can be suitable for use with World Wide Web applications.

geopicts IN-FORMAT [IN-PARAMS] IN-TYPE IN-PATH [PROC-PARAMS] \
         [OUT-FORMAT] [OUT-PARAMS] OUT-PATH PICT-PATHS

• IN-FORMAT [IN-PARAMS] and IN-PATH are the input file format, its parameters (if any) and path; use show formats for a list of the currently accepted formats;
• IN-TYPE is the data type to read; the possible types are
  • TR, a track: the time-stamp of each file is compared with the track points time-stamps and a position is computed by linear interpolation/extrapolation; strange results can be caused by track points being widely apart in distance or time;
  • GR, a group: the files are sorted by their time-stamps in increasing order and each file is put into correspondence with a waypoint in the group in the order they appear there, undefined waypoints being discarded; if there are more files than waypoints, the last waypoint is used for the remaining files;
• PROC-PARAMS, the processing parameters can be
  • id=ID gives the name or identifier number of the item to be used from the input file; if not given the last item of IN-TYPE that was read in is used;
  • date=DMODE describes how file time-stamps should be retrieved, DMODE being
    • pict (the default): the file is a picture file, the time-stamp should be got from the EXIF tags in the file; the following methods will be tried in sequence: using the Tcl exif package, running the exif or the metacam external utilities; if all of them fail, the file is discarded;
    • exif: the file is in the EXIF format (as produced by exif or metacam) and the time-stamp is retrieved from the EXIF tag;
    • fmod: the file last modification time as given by the operating system is taken as time-stamp;
  • dh=DHOUR: gives the difference in hours of the time zones of the track and files time-stamps, a positive value meaning the track time is later than the files times; useful when the camera and the GPS receiver are not set to the same time zone;
• OUT-FORMAT and OUT-PATH are the output file format and path; at present the only supported format is GPX;
• OUT-PARAMS are the parameters for OUT-FORMAT but may also contain the following ones used when generating the resulting waypoints
  • datum=DATUM;
  • sy=SYMBOL, with SYMBOL the internal name of the symbol; use show symbols for a list of the symbol names;
  • prefix=STRING gives the prefix of the waypoint names, the default being P; each name starts with the prefix and is followed by a 5 digit number;
• PICT-PATHS are the paths to the files to be geo-referenced.

A file with a time-stamp already found will be discarded.

Example: the following command

gpsman.tcl geopicts gpsman TR data/Esp.trk date=exif dh=1 \
    gpx lacpicts.gpx photo/exifs/LaC-*

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The geopicts Command