| | | Terminology |
Here is a list of a few terms that will be used below.
Waypoints, routes, and tracks are examples of data used in GPS receivers. A waypoint (sometimes abbreviated to WP) describes a precise location through its geographic coordinates. A sequence of waypoints is called a route (RT) and is defined by the user. A track (TR, also called a trail in Lowrance receivers) is a sequence of track points (TPs) recorded by the GPS receiver over a time period and giving the positions of the receiver during that period, and including if possible the altitude and the depth (in meters).
Route stages are the parts of a route between each two consecutive waypoints. Route stages are called edges in Graph Theory, legs in aviation, and links by Garmin. At present, GPSMan deals with three data fields for each stage: a comment, a label (that will appear in the map), and hidden information.
Data items refer to the elements stored in the GPSMan data-base. Apart from data items the GPS receivers use, groups (GRs) of such items can be defined and used.
Forgetting a data item means deleting it permanently from the data-base.
Input/Output operations in GPSMan have the following names (see below for the definitions of the GPSMan file formats):
A unique name is used for each item of each type. When a new item is read in that has the same name as an item of the same type in the data-base, either the latter is forgotten, or the new item gets a new name, according to an option. Choosing to forget the previous item is recommended as it is the behaviour of most GPS receivers, and because this will avoid having obsolete information in the data-base. Obviously it should be noted that in this case all input operations are destructive: new items will replace data-base items having the same name.
Irrespective of the selected option, replacement is always done when the items with the same name are waypoints with exactly the same position. Note however that the test for the positions being the same may fail because of rounding errors when the comparison implies a change of position format or a change of datum.
When an item is renamed, its previous name is kept in the remark field.
Allowed characters in names of waypoints depend on the brand of the receiver. Garmin names can only have uppercase letters and digits, even if Garmin receivers may use others (see the Garmin specification...). GPSMan also accepts lowercase letters if the existing option on this was set by the user, and hifens. Lowrance names can have uppercase letters, digits, hifen, single quote, period, parentheses, slash and also space. If data files are to be shared among users with receivers of different brands, the more strict rules (those of Garmin, at present) should be followed.
When a name with characters not allowed is read from a file or from the receiver, the user is asked for a new name. A name of a waypoint already in the data-base will not be accepted. Cancelling the renaming makes the waypont to be ignored, what may cause inconsistency if it belongs to a route.
Comments and remarks (NB) can be specified for some items. The difference is that comments can be got from and put into the GPS receiver, while remarks are only kept by the interface and may be saved to and loaded from GPSMan files. The syntax for comments depends on what the receiver accepts. The syntax for remarks is free: any ASCII character, any length, although no blank lines are allowed.
GPSMan User Manualmig_at_ncc.up.pt, DCC-FC & LIACC,
Universidade do Porto, 2002 | | | Terminology |