GPS Manager User Manual -- The geopicts Command

|  |  | 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

where

- `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-*

uses the track in GPSMan format in file `data/Esp.trk` and the EXIF files `photo/exifs/LaC-*`, which have time-stamps 1 hour later than the time-stamps in the track, in producing the GPX file `lacpicts.gpx`.

|  |  | The `geopicts` Command