A map is the key element for Land/Air, they allow you to geographically and visually situate the tracks you download.
Characteristics
A map is a flat graphical representation of a portion of the earth’s surface. A map presents several characteristics, the main ones:
•System of coordinates: This is a table of latitude and longitude readings, based on the meridians and parallels that indicate the relative situation of a point on the earth’s surface.
•Scale: The relation between the dimensions of the elements drawn on the map and their real value, measured on the earth’s surface.
•Cartographic projections: All maps are approximate representations of the earth’s surface. They are only approximate representations because the earth’s round surface has been drawn on a flat surface. The creation of map employs a method that associates each point on the earth’s surface with a point drawn on a map. Different types of cartographic systems are used to make this association between the earth and map’s points.
There are several different types of cartographic projection that are classified depending on the areas they cover. Land/Air allows you to choose the most adequate system for your un-calibrated map, such as: U.T.M., Lat > Long, Mercator, France Lambert I... You can also choose the automatic calibration, which will leave Land/Air to decide which is the best cartographic system for the map you want to calibrate.
•Datums: Any line or point on the surface used as a reference unit to measure another unit. Basic and reference point on the surface that is used as the origin of all the coordinates of the network. Land/Air allows you to choose the adequate datum for your un-calibrated map, i.e. WGS 84, European 79...
Types
The maps used by Land/Air can be divided into two different types: raster maps and vectorial maps.
•Raster maps: A raster map is a picture that contains all the map’s information. When these maps are digitalized (bit map .bmp format) each pixel represents a set of adjacent coordinates that have to be defined (calibrated). To be able to use these maps with Land/Air you have to make sure that they have been calibrated.
•Vectorial maps: These maps contain precise information about position, longitude and size all geographical entities. This normally consists in a list of 2D coordinates (lines) that marks the boundaries of the different elements. A vectorial map is the most adequate method to identify objects that can be individually identified whenever you need greater precision.
•3D map (relief *.CDEM): Digital elevation models, consisting of a grid of points that make up the orography of the terrain. Depending on the distances between these points, the emphasis is more or less accurate.
Download and map scanning
Land/Air uses with maps downloaded from the Internet or scanned from somewhere:
•Internet download: Land/Air features direct links so that you can download public and free maps from the Internet.
•Scanning maps: The other possibility you have is to scan a map. This map will have to be calibrated before you use it.