Toolbar button actions:
Select map: Allows to switch between different maps.
In case multiple map service setups have been configured in the loaded file (see chapter Configuration), this will show a dialog to select one of them to become the active setup.
The current zoom level, view location and display settings will remain as they are, as long as the new map service supports those settings (some services have a more limited zoom range than others).
Offline mode: Turns network access on and off for map tile retrieval.
Allows to switch the viewer into an offline mode to prevent it from attempting to download missing map tiles. Such missing tiles will simply show as empty squares (with the window background color).
This allows to have a smoother user interface responsiveness in case of a slow or disconnected network without having to maintain a separate offline setup in the configuration which only uses the local file cache.
Refresh tiles: Refreshes all currently visible map tiles.
Refreshes all currently visible map tiles from the underlying map service to make certain that they are up-to-date. This will bypass any configured caches (both memory and disk) and force the tiles to be loaded again via available internet connection. The updated tiles will then replace the ones in the caches.
Download tiles: Downloads currently visible map tiles.
Shows a dialog to download various subsets of the tiles in the currently visible map area.
This is only possible when tile cache information is enabled as it builds the subsets from that information. When the tile cache zoom level differs from the currently displayed zoom level of the map, this will download the tiles of the current tile cache zoom level. That level is restricted to the range between the current map zoom level (as lower bound) and maximum five levels above that. This ensures that the number of tiles remains in a reasonable range.
The dialog offers to download the following tile subsets:
All visible tiles
Any missing tiles
Any outdated tiles
All locally available tiles
The download can be interrupted at any time after starting it, but the dialog remains blocking any other operations in the meantime.
Zoom in/out: Changes the level of detail on the visible map area.
This will change the zoom level and might thus require to fetch a new set of map tiles for display. Note that different map services might have different zoom ranges.
Zooming in will enlarge the map on screen while keeping the same location at the center, thus showing more details around that area.
Zooming out will reduce the size of the map on screen while also keeping the same location at the center, thus providing more overview around that area.
Toggle tile grid display: Changes visibility of the map tile grid.
This allows to see the boundaries of the map tiles currently visible. The color of the grid lines and the font and color of the tile coordinates text can currently only be configured in the file (see chapter Configuration).
Toggle scale info display: Changes visibility of the scale information overlay.
This allows to (roughly) measure distances on the currently visible map area. Note that there are three distinct overlays for the top and bottom boundaries of the currently visible area and at the (vertical) center.
This is necessary as a consequence of the map tile data nature: all available map services use the so called Mercator Projection to map the surface of the earth onto a square area. This leads to a distortion of the map data that is dependent on the latitude being shown. Hence distance scale changes in North-South direction (e.g. vertically).
At large zoom levels (e.g. with a great level of detail), the distortion becomes more and more negligible. But in order to make the situation transparent, the scale information is always displayed for top/center/bottom.
Information display on toolbar:
Scale: Displays the current map scale.
The map scale determines the size (pixel resolution) of the map tiles. This is currently only supported by Google Maps and can only be configured in the file (see chapter Configuration).
Note that this is primarily intended for high-resolution displays and does not contain more details on the map tiles. It can, however, be used to enlarge the map for better readability of small text labels. Depending on the chosen scale, the map tile images become larger and thus consume more memory and disk space.
Zoom: Displays the current zoom level.
The zoom level determines the amount of detail on the map tiles. Increasing zoom levels correspond to more details being shown and each map tile covering a smaller area, with each zoom level step doubling the resolution of the map.
Coordinates: Displays the longitude and latitude at the current cursor position.
Both longitude and latitude are shown in signed decimal as well as in degrees, minutes and seconds with East/West resp. North/South direction.
Mouse interaction possibilities:
Left click and drag: Moves the visible area of the map in the dragged direction.
Wheel scroll up/down: Zooms in/out while centering at the current mouse cursor position.
CTRL + Left button click: Appends the location at the clicked mouse cursor position to the currently selected track segment, route or as a waypoint.
Left button double click: Zooms in while centering at the current mouse cursor position.
Right button click: Displays a popup menu with actions for the current mouse cursor position.
Middle button (single) click: Centers the map at the clicked mouse cursor position.