gpx(3tcl) GPS eXchange Format (GPX) gpx(3tcl)
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NAME
gpx - Extracts waypoints, tracks and routes from GPX files
SYNOPSIS
package require Tcl 8.5
package require gpx ?0.9?
::gpx::Create gpxFilename ?rawXML?
::gpx::Cleanup token
::gpx::GetGPXMetadata token
::gpx::GetWaypointCount token
::gpx::GetAllWaypoints token
::gpx::GetTrackCount token
::gpx::GetTrackMetadata token whichTrack
::gpx::GetTrackPoints token whichTrack
::gpx::GetRouteCount token
::gpx::GetRouteMetadata token whichRoute
::gpx::GetRoutePoints token whichRoute
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DESCRIPTION
This module parses and extracts waypoints, tracks, routes and metadata
from a GPX (GPS eXchange) file. Both GPX version 1.0 and 1.1 are sup-
ported.
COMMANDS
::gpx::Create gpxFilename ?rawXML?
The ::gpx::Create is the first command called to process GPX
data. It takes the GPX data from either the rawXML parameter if
present or from the contents of gpxFilename, and parses it using
tdom. It returns a token value that is used by all the other
commands.
::gpx::Cleanup token
This procedure cleans up resources associated with token. It is
strongly recommended that you call this function after you are
done with a given GPX file. Not doing so will result in memory
not being freed, and if your app calls ::gpx::Create enough
times, the memory leak could cause a performance hit...or worse.
::gpx::GetGPXMetadata token
This procedure returns a dictionary of the metadata associated
with the GPX data identified by token. The format of the meta-
data dictionary is described below, but keys version and creator
will always be present.
::gpx::GetWaypointCount token
This procedure returns the number of waypoints defined in the
GPX data identified by token.
::gpx::GetAllWaypoints token
This procedure returns the a list of waypoints defined in the
GPX data identified by token. The format of each waypoint item
is described below.
::gpx::GetTrackCount token
This procedure returns the number of tracks defined in the GPX
data identified by token.
::gpx::GetTrackMetadata token whichTrack
This procedure returns a dictionary of the metadata associated
track number whichTrack (1 based) in the GPX data identified by
token. The format of the metadata dictionary is described be-
low.
::gpx::GetTrackPoints token whichTrack
The procedure returns a list of track points comprising track
number whichTrack (1 based) in the GPX data identified by token.
The format of the metadata dictionary is described below.
::gpx::GetRouteCount token
This procedure returns the number of routes defined in the GPX
data identified by token.
::gpx::GetRouteMetadata token whichRoute
This procedure returns a dictionary of the metadata associated
route number whichRoute (1 based) in the GPX data identified by
token. The format of the metadata dictionary is described be-
low.
::gpx::GetRoutePoints token whichRoute
The procedure returns a list of route points comprising route
number whichRoute (1 based) in the GPX data identified by token.
The format of the metadata dictionary is described below.
DATA STRUCTURES
metadata dictionary
The metadata associated with either the GPX document, a track, a
route, a waypoint, a track point or route point is returned in a
dictionary. The keys of that dictionary will be whatever op-
tional GPX elements are present. The value for each key depends
on the GPX schema for that element. For example, the value for a
version key will be a string, while for a link key will be a
sub-dictionary with keys href and optionally text and type.
point item
Each item in a track or route list of points consists of a list
of three elements: latitude, longitude and metadata dictionary.
Latitude and longitude are decimal numbers. The metadata dictio-
nary format is described above. For points in a track, typically
there will always be ele (elevation) and time metadata keys.
EXAMPLE
% set token [::gpx::Create myGpxFile.gpx]
% set version [dict get [::gpx::GetGPXMetadata $token] version]
% set trackCnt [::gpx::GetTrackCount $token]
% set firstPoint [lindex [::gpx::GetTrackPoints $token 1] 0]
% lassign $firstPoint lat lon ptMetadata
% puts "first point in the first track is at $lat, $lon"
% if {[dict exists $ptMetadata ele]} {
puts "at elevation [dict get $ptMetadata ele] meters"
}
% ::gpx::Cleanup $token
REFERENCES
[1] GPX: the GPS Exchange Format (http://www.topografix.com/gpx.asp)
[2] GPX 1.1 Schema Documentation (http://www.to-
pografix.com/GPX/1/1/)
[3] GPX 1.0 Developer's Manual (http://www.topografix.com/gpx_man-
ual.asp)
AUTHOR
Keith Vetter
BUGS, IDEAS, FEEDBACK
This document, and the package it describes, will undoubtedly contain
bugs and other problems. Please report such in the category gpx of the
Tcllib Trackers [http://core.tcl.tk/tcllib/reportlist]. Please also
report any ideas for enhancements you may have for either package
and/or documentation.
When proposing code changes, please provide unified diffs, i.e the out-
put of diff -u.
Note further that attachments are strongly preferred over inlined
patches. Attachments can be made by going to the Edit form of the
ticket immediately after its creation, and then using the left-most
button in the secondary navigation bar.
KEYWORDS
gps, gpx
CATEGORY
File formats
COPYRIGHT
Copyright (c) 2010, Keith Vetter <kvetter@gmail.com>
tcllib 0.9 gpx(3tcl)