The X/Y diagram is a graphic tool for analyzing and visualizing tracks and routes. Speed and altitude can be evaluated in relation to the distance travelled or in relation to time.

At a glance, you can visualize information such as:

• Speed profile - Where and when did I reach my maximum and minimum travelling speeds?
• Altitude profile - At wihich distances or travel times from the start did I reach which elevation levels?
• How does the cumlative elevation curve look like (ascending / descending)?
• For para- and deltagliders or sailplanes: How does the plot of my vertical speeds look like? How does my elevation plot look like when it is expresses as altitude above ground?
• You can also place the cursor with a simple click on every point along the curve and select Show in x-Plorer to see the corresponding data set.  map cursor will be centered at the cooresponding point along the track in the map winow and vive-vera.
• You can also plot various tracks or routes at a time, so you can also compare various competitors or various rounds of a given course. For the latter it is necessary to devide the tracklog in seoerate rounds. If you want to plot tracks over time and compare several tracks, it is obligate to convert the time stamps into time travelled since start using the Track Processor.

To generate a X/Y diagram simply mark the tracks or routes which you want to plot and click the icon in the X-Plorer symbol bar. The X/Y diagramm will open in a seperate window. You can zoom or drag-and drop the diagramm within the window wherever you like. For zooming use the webwheel of you mouse, the zoom will be centerd at the mouse position.

You find an example of an altitude profile below:

The diagram line is automatically calculated from the data available. Depending on the characteristics of the datset, various analyses can be performed.

X-Axis

You have three different units availabel along the X axis: Point number, distance traveled or time. The consecutive number and distance can always be extracted from the tracklog while time axis can only be displayed if the track or route point have a time stamp. Please not the when you plot a curve with Point number as units along the X-axis, the distance between point will always be the same. However, in ther real world, this might correspond to completely differnt distances when those are expressed in kilometers or miles. You an altitude profil may cook pretty “distorted”.

Y-Axis

You have many parameter options which you can assign to the Y-axis: Horizontal and vertical speed, altitude (usually from GPS), altitude of the surface relief (according to the DEM), altitude above ground, cumulative elevation curce ascending, and cumulative elevation curve descending.

Of course, speed and altitude values mus also be available in the database (tracklog or route). The altitude according to the DEM is always interpolated from the raster of the active DEM, so this function requires a DEM to be installed an the accuracy of the values will vary with the DEM used. For further information please refer to QV System - Map Datums, Grids and DEMs.

Vertical speed is calculated from altitude and time differences of consecutive track points. Thus, this information is only available if data on altitude and time is available in the tracklog or route.

If your tracklog only includes coordinates (including elevation), you will at least be able to generate an altitude profile. If your tracklog includes time stamps but no speed and course information, you can generate these values using the Track Processor. However, please note that those values do not represent instantaneous values (as the ones from a GPS) but average values which are calculated from distance and time differences between points. This has to be considered when interprating the results.

The diagram is always plotted according to the style definition which you have set for the plotted track or route. The scaling is automatically calibrated according to the window size. However you can zoom the diagram using your mouse wheel and you can also drag-and drop it to the desired position within the window.

You can read various sets of values from the diagram using the mouse pointer. These are displayed in the status line at the bottom of the X/Y diagram window:

  x=…    y=…   Shows the X- and Y- values of the mouse pointer in the units selected.

dx=…  dy=…   Shows the differences in X- and Y- values between the cursor and the mouse pointer in the units selected.