NAME

Image::Synchronize::GpsPositionCollection - Manage a collection of GPS positions

METHODS

The module provides the following methods:

new

  $gpc = Image::Synchronize::GpsPositionCollection->new;

Creates and returns a new instance of the class.

add

  $gpc->add($time, $latitude, $longitude, $altitude, $id, $scope);

Adds a point to the track with the specified $id, for the specified $scope. The data of the point include the $time (as from gmtime), the $latitude in degrees (positive to the north, negative to the south), the $longitude in degrees (positive to the east, negative to the west), and the $altitude in meters.

Returns the Image::Synchronize::GpsPositionCollection itself.

ids_for_track

  @ids_for_track = $gpc->ids_for_track($scope);
  @ids_for_track = $gpc->ids_for_track; # all scopes

Returns a list of track IDs for the specified $scope, or for all scopes.

Note that a given $scope includes all other scopes whose names have $scope as their prefix. So, scope 'foo/bar' includes scopes 'foo/barbar' and 'foo/bar/bar', but not scope 'foo/fie'.

points_for_track

  $points = $gpc->points_for_track($track_id);

Returns a reference to the array of track points for the track with the specified $track_id, or undef if that track is not known.

extreme_times_for_track

  ($min_time, $max_time) = $gpc->extreme_times_for_track($track_id);

Returns the least and greatest times of any points in the track with the specified $track_id, or undef if that track is not known.

middle_bounding_box_for_track

  ($latitude, $longitude) = $gpc->middle_bounding_box_for_track($track_id);

Returns the coordinates of the middle of the bounding box of the track with the specified $track_id, or undef if that track is not known.

The bounding box touches the points with the least and greatest longitudes and latitudes.

reduce

  $gpc->reduce;

Ensures that for each GPS track the points are sorted in ascending order of time, and that there are no duplicate times. This is needed by position_for_time.

tracks_for_time

  @ids_for_track = $gpc->tracks_for_time($time, $scope);
  @ids_for_track = $gpc->tracks_for_time($time); # all scopes

Returns the @ids_for_track, for the specified $scope or all scopes, that cover the $time, i.e., for which the $time is greater than or equal to the oldest time of the track and the $time is less than or equal to the youngest time of the track.

Note that a given $scope includes all other scopes whose names have $scope as their prefix. So, scope 'foo/bar' includes scopes 'foo/barbar' and 'foo/bar/bar', but not scope 'foo/fie'.

Returns the empty list if no tracks cover the time (within the scope, if specified).

position_for_time

  %positions = $gpc->position_for_time($time,
                                       scope => $scope,
                                       track => $track_id);

Returns the GPS positions for the indicated $time, $scope, and/or $track_id, or an empty list if no matching positions are known.

The returned @positions contains a reference to a hash for each found position. The hash contains keys 'track', 'scope', and 'position'. The value for the first key is the track ID. The value for the second key is the scope. The value for the last key is a reference to an array with elements [$longitude, $latitude, $altitude]. The positions are sorted by decreasing scope length.

  $index = search($target, $count, $get);

Searches for the $target in an array of $count elements sorted in non-descending order. The array elements are accessed through $get, which may be an array reference or a code reference. If it is a code reference, then the elements of the array are accessed through $get->($index).

Returns the greatest element $index for which the element is equal to or less than the $target. If the $target is less than the first element of the array, then returns -1.

DEPENDENCIES

This module uses the following non-core Perl module:

  • Image::Synchronize::Timerange;

  • namespace::clean

  • YAML::Any

AUTHOR

Louis Strous <LS@quae.nl>

LICENSE AND COPYRIGHT

Copyright (c) 2018 - 2020 Louis Strous.

This program is free software; you can redistribute it and/or modify it under the same terms as Perl itself.