MapSend Topo — How detailed is it?
MapSend Topo uses a different technique than Garmin when it comes to how the data is stored. In the Garmin topo offering, the topographic lines are stored as actual lines, similar to how roads and rivers are stored. This means that the Garmin topographical data is fixed as how it is presented. Magellan, on the other hand, overlays a grid over the whole country. The height is known at every point on the grid. Because of the way that the data is organized, it can be stored quite compactly, probably using techniques borrowed from image compression. This means that a lot of topo data can fit into a relatively small space. This also allows the Meridian to do such tricks as showing the elevation along a route, and to change contour lines from meter to feet. Conventional paper topographical maps have a stated VERTICAL resolution, where each line represents a change in elevation of a certain amount. Magellan Topo, however, has a HORIZONTAL resolution of 90 meters. This means that the grid that
MapSend Topo uses a different technique than Garmin when it comes to how the data is stored. In the Garmin topo offering, the topographic lines are stored as actual lines, similar to how roads and rivers are stored. This means that the Garmin topographical data is fixed as how it is presented. Magellan, on the other hand, overlays a grid over the whole country. The height is known at every point on the grid. Because of the way that the data is organized, it can be stored quite compactly, probably using techniques borrowed from image compression. This means that a lot of topo data can fit into a relatively small space. This also allows the Meridian to do such tricks as showing the elevation along a route, and to change contour lines from meter to feet. Conventional paper topographical maps have a stated VERTICAL resolution, where each line represents a change in elevation of a certain amount. Magellan Topo, however, has a HORIZONTAL resolution of 90 meters. This means that the grid that
