17. Elevation Profile¶
This dock window shows the ground elevation, flight plan with cruise, climb, descent legs and altitude restrictions together with all flight plan waypoints. It is only available when a flight plan is loaded. The user aircraft will be shown if Little Navmap is connected to the simulator.
The elevation display covers only the flight plan and will not change the depiction if you get off the flight plan with your simulator aircraft. You need a valid flight plan (i.e. a departure and destination) to see the elevation profile.
The elevation profile also does not cover missed approaches and legs to alternate airports. Create a new flight plan from the destination to the alternate airport if you wish to use the elevation profile.
Movement of the aircraft in the elevation profile is tied to the active flight plan leg and will not be correct if flying away from the active leg.
17.1. Top Label¶
Additional information is shown in a label on top of the window if the mouse is hovered over the diagram. The corresponding position is highlighted on the map with a black/cyan circle.
Following information is shown in the top label if connected to a flight simulator:
- Distance from user aircraft to flight plan destination
- Distance to the top of descent
To Destination: 118 nm, to Top of Descent: 95 nm.
In addition, the information below is shown in the top label when hovering the mouse over the diagram:
- From and to waypoint for the flight plan leg at the cursor position
- Distance from departure and to destination from the position of the mouse cursor.
- Ground elevation at cursor position.
- Flight plan altitude above ground considering cruise altitude as well as climb and descent slopes.
- Safe altitude for the flight plan leg at the cursor position corresponding to the orange line.
- Wind direction, speed and tail- (
►) or headwind (
ANDOR ► SJA, 38 nm ► 112 nm, Ground Elevation 984 ft, Above Ground Altitude 8,016 ft, Leg Safe Altitude 3,000 ft, Wind 227°M, 14 kts, ► 9 kts
17.3. Zoom Sliders¶
The right side of the elevation profile contains the zoom sliders. The following controls are available:
Splitter: You can resize the right part of the elevation profile window using this splitter button. The part containing the sliders will be collapsed if you drag it to the far right. You can open the collapsed part again by dragging the splitter to the left.
Expand to Window: Resets the view back to 100 percent showing the whole flight plan.
Zoom Vertically: Move the slider up to zoom in vertically. Maximum zoom results in 500 ft height for the whole profile window.
Zoom Horizontally: Move the slider up to zoom in horizontally. Maximum zoom results in about 4 nm distance for the whole profile window.
17.4. Mouse Movement¶
- Hover: The corresponding position within the flight plan is highlighted on the map with a black/cyan circle.
Wheel: Zoom in and out horizontally.
Shift+Wheel: Zoom in and out vertically.
Left Click and drag: Move map up, down, left or right.
Left Double Click: Zoom to position on main map.
Right Click: Show context menu.
17.5. Keyboard Movement¶
Click on the elevation profile window to activate it before using the keyboard.
- Cursor keys: Move map up, down, left or right.
-: Also on numpad. Zoom in and out horizontally.
/: Also on numpad. Zoom in and out vertically.
Ins: Reset view to 100 percent and show the whole flight plan.
End: Jump to departure or destination.
PageDown: Move forward or backward one page.
17.7. Profile Display¶
The colors and symbols of the elevation profile follow the style of the main map as set in the options dialog. Colors, patterns and symbols for airports, navaids, procedures, active and passed flight plan legs are the same. The profile display also follows other map settings like visibility of flight plan line, aircraft and aircraft trail.
Aircraft heading will turn if a backward movement relative to the active flight plan leg is detected.
For more information see the Elevation Profile.
The elevation profile uses actual altitude for display of restrictions, slope and cruise. You have to expect differences between actual and indicated altitude when flying above transition altitude using the standard altimeter setting of 29.92 inches.
Note that the profile display depends on the correct sequencing of the active flight plan leg (magenta line). The aircraft will be displayed in the wrong position and the aircraft trail will be erratic if the active leg is not correct or manually changed.
The aircraft trail will be displayed incorrectly in the elevation profile if the flight plan is changed (i.e. the flight plan length or geometry changes). You can delete the profile aircraft trail in context menu Delete Aircraft Trail while keeping the trail on the map.
17.8. Top of Climb and Top of Descent Paths¶
The elevation profile will also display the top of climb and top of descent which are calculated based on the current Aircraft Performance profile and wind situation.
Note that the TOC and TOD calculation is influenced by altitude restrictions in procedures. Little Navmap will calculate a climb or descent path always adhering to restrictions. The resulting path might use a higher or lower climb or descent speed than expected.
The path is also forced to the lowest allowed altitude at the final approach fix and the final approach course fix to avoid arriving above the ILS glide slope or too high at the destination runway.
You can safely follow the descent path as shown by Little Navmap, provided you can manage your aircraft speed at the same time. For large aircraft you might want to descent around 10 nm earlier to reduce speed to 250 knots below 10000 feet.
The climb and descent paths are affected by wind and are moved accordingly for strong head- or tailwinds. The climb path will be steeper in the elevation profile if you climb in a strong head wind, for example.
See chapter Winds Aloft for more information.
The plan will switch to a flat display showing only a flight plan line at cruise altitude if the TOC and/or TOD cannot be calculated or if the plan violates altitude restrictions. A red warning message is displayed if this is the case.
17.9. Elevation Data¶
Elevation processing is done in the background since data has to be downloaded and computation is CPU intensive. Therefore, the update of the elevation display can take from a few seconds up to half a minute. This background update is started after creating or changing the flight plan or when new elevation data was downloaded. The display will be updated accordingly whenever new data is available.
Flight Plan Elevation Profile window if you think that it
causes performance problems or stutters. All updates will stop once the
window is closed.
17.9.1. Online Elevation Data¶
Note that the online elevation data does not cover all countries and currently ends at 60 degrees north. The data contains several known errors.
The calculation of online elevation points is limited to flight plan segments not longer than 2000 nautical miles to avoid overloading. Add more waypoints or calculate a flight plan to avoid this limitation.
17.9.2. Offline Elevation Data¶
Using the recommended freely downloadable GLOBE - Global Land One-km Base Elevation Project elevation data has several advantages:
- Faster updates
- World wide coverage
- No known errors
- Display of altitude below the cursor in the status bar
See Flight Plan Elevation Profile in the options dialog for instructions how to download and install the GLOBE data.