Coordinates

A geographic coordinate is nothing else than a defined point on the suface of the earth. Each waypoint, each track point and each GPS online position refers to a coordinate. In other words: when talking about GPS navigation we always refer to coordinates.

In the simplest way, a coordinate refers to two angular values, the lattitude and the longitude. However, in reality, things are a littel more complex because many different coordinate systems are existing which vary bothh in the units used and also in the map reference system (map datum). In any case, they are all use to define points on the surface of the earth.

The common units are degrees, meters and - less common - gons. The map reference system (map datum) is a mathematical model to describe the spheric surface of the earth which is not a perfect ball but a rather irregular speroid. Thus, depending on the area to be described, different values for the radius, geometric flattening, etc. are use in order to increase the accuracy of the model.

A good explanation on the basics can be found under this link http://en.wikipedia.org/wiki/Geographic_coordinate_system.

The good news about it: You don not have to worry too much about it because QV does the job for you: Internally, it will always work in the standard lattitude and longitude system using the global reference system WGS84. However, you can use for display or data input any other unit or map datum. Just click the icon Units in the standard symbol bar, see chapter Units.

The presently selected map datum will be displayed in the map window on the righthand side of the status line at the lower map window margin but also in the status line of the QV Xplorer, in this case on the lefthand side:

In the example shown, the selected map reference system is WGS 84, and the unit chosen is decimal degrees, so DD.DDDDD .

Please note that the map datum and units setting selected are always valid system wide, so the settings will be applied to all map and Xplorer windows.

You can enter and/or modify coordinates in QV at various instances:

• In the detail window of the Xplorer in order to modify coordinates of waypoints and trackpoints
• In the map calibration assistant
• In the dialog box Search point according to coordinates

During coordinate input, please follow these guidlines:

• You must enter the coordinates in the selected format. So, for instance, if you have selected UTM, you cannot enter coordinates in decimal degrees (DD.DDDD).
• A Tooltip will appear when you position your mouse on the data entry field and will show a description on the format in which data have to be entered and some samples on possible notations:
• QV will check the correct formatting during data entry and will highlight the data input field in orange to indicate when formatting is wrong. In the example given below 200° west has been entered which is un unplausible value:
• Despite these rules which have to be followed, QV is rather tolerant during data entry (in terms of pad charcters, comas, etc). However it is important that the numerical values are clearly seperated and that the number of expected signs is entered. Some examples: In case decimal degrees (DD.DDDD)is selected as format, QV will expect 2 numerical values. So would be a valid entry 50 12 and would be interprated as 50° North and 12° East; however, you can also enter N50° O12.0°. Another example: If degrees, decimal minutes (DD MM.MMM) is selected, QV will expect 4 numerical values. So you can enter S22°30 E18°10.5' but also -22 30 18 10.5 schreiben.
• The hemissphere is indicated by the letters N,S,W,E/O or by minus “-” for S and W; without an explicite indication, positive values are interpreted as N ans E, respectively.
• QV erwartet immer den Breitengrad bzw. den Hochwert als erstes und Längengrad bzw. Rechtswert als zweiten Wert.
• You can use comma or point as decimal delimiter.
• You can also enter coordinates from other applications using copy and paste.

Following a couple of examples for valid entries: