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Forms of Digital mapping
1. Raster maps: Digital mapping is available to cover all of Australia. This mapping is usually scanned from paper versions, and is called raster mapping. (Raster, because it is made up of collections of pixels, or is a bitmap).
Raster mapping has the advantage of reproducing exactly what we see on paper, including shading, colouring, features and contour lines. Raster maps are one scale only, you cannot decrease the scale without losing resolution, because the image becomes "pixelated".
2. Vector maps: The other type of digital mapping is called vector mapping. This is because it is made up of simple instructions like a program. For example:
10. Join points 2 and 3 with a red line 2mm thick.
20. Join points 2 and 4 with a black line 0.5mm thick.
and so on.
Vextor mapping has the advantage of being able to be searched for names, words and phrases. In effect, it is its own database, so is much more useful in a "find where" situation. It is also scaleable, that is it remains in focus regardless of scale.
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Using maps in GPS
Raster mapping:
This type of mapping is used by programs such as Trax, Fugawi or Oziexplorer, for use on a computer or PDA. Raster mapping cannot be loaded into any Garmin GPS, even the so-called map models.
You can however, load points and routes from the maps, in to any Garmin GPS. You can do this manually, or by computer link, using Fugawi or Oziexplorer programs. Raster maps are produced in Australia by Geoscience, Sunmap and Maptrax. Memory-Map also uses raster maps.
Vector mapping:
GPS, whether hand-held, marine, or in-car, is used mainly to guide you to a destination. Vector mapping is more effective in GPS, because it is searchable for names and places.Vector mapping is also used in GIS products.
All the cartography, marine and land, supplied by Garmin, is in vector form for more effective "find" and guide functions. Vector mapping is released by Garmin worldwide under the Mapsource brand. Other vector mapping is supplied by Geoscience and Johnny Appleseed GPS. |