Settings
Map - Settings
On this page you can set the maps storage location and the map
basic data.
- Maps
-
As loaction for the map data for Maemo (Nokia Internet Tablet)
you should define a directory on one of the SD cards. With the help of
the button Maps you can open a directory selection dialog and
navigate to the SD card locations to find under /media/mmc[1|2].
In the text field beside the button you can see the current selection.
You can modify the text field also by hand and set so your preferred location.
- Projection
- The coordinate points of the raw maps Cumulus uses are not projected.
They are coded according to WGS84 datum. Therefore all these points are
projected on first loading. There are many types of map projections available.
You need a projection because the earth is a sphere (or close to it) and your
map is flat.
Cumulus supports two projections:
- Plate Carrée - Equidistant Cylindrical Projection
- Lambert - Conical Orthomorphic Projection
The first is computationally simpler and thus the preferred one in Cumulus.
The latter is more complex, so your maps will take much longer on first load
but it is more realistic.
Each map projection needs a basis from where to work. For the Plate
Carrée projection choose a parallel close to your home base.
If the option Projection follows Home Position is activated, the
parallel is automatically set to the latitude of your Home Position in the
assumption that the Home Position is your preferred flight space. That ensures
an unskewed map display and you are not forced to set this parallel by hand.
That is the default setting.
For Lambert
projection you should select the parallels so that they are covering the area
you are flying. For example, you could choose the
parallels from your official flying map. Then you will have an equal
look like these maps. You should select the longitude from the middle
of the area you are flying. It is needed because of some technical
reasons not for the projection itself. No automatic update of projection data
is done here. You must do that always by hand. Therefore use this kind of
projection only, if you are familiar with the Lambert projection.
After changing the projection kind or the standard
parallel values Cumulus is forced to recompile your map files. Please
note that: If you don't set the projection options correctly,
you will likely end up with a blue screen or a skewed map. This
is especially so if you are far away from the coordinates used in the
projection!
- Map Management
- Cumulus supports two strategies for keeping maps in memory.
Maps are only loaded if needed, but they can either stay there until
they really need to be moved out of memory, or they can be removed
sooner. The first strategy is more suited for users who want to zoom in
and out a lot and have plenty of memory in their device, the latter
strategy is the default one and to be recommended for people with
lower memory devices.