Type
The type defines the general purpose of the device.
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Echo sounder. Echo sounders are devices designed to study water bodies using sonar. The principle of operation of an echo sounder is similar to that of a radar, but it does not use radio waves, but ultrasound. The initial purpose of such devices is the creation of topographic maps of the bottom of a reservoir, the determination of its topography and depth in various places. However, in addition to this, the echo sounder can be used to detect fish, and with good quality of the device and correctly set settings, you can even determine the approximate size of potential prey.
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Chartplotter. A chartplotter can be described as a dedicated GPS navigator designed for marine use and equipped with related additional features. Such functions include, at a minimum, working with sailing directions (detailed maps of water bodies, indicating depths, currents, etc.); in addition, support for meteorological services, additional equipment such as radars or specific navigation sensors, etc. can be provided. Note that the GPS receiver can be either built-in or external; see Chartplotter Specifications for details.
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Sonar chart plotter. Models that combine the capabilities of both types described above in one device. Such devices are the most versatile, however, and cost accordingly.
— Sonar fl
...asher. A specific type of echo sounder, designed specifically for use in one place, without movement. Initially, such devices were generally developed for fishing from an ice hole in winter — although this is not limited to such fishing — flashers are also used in summer, including in open water when fishing from a boat. Such devices are by definition capable of displaying fish in real time (see "Functions"), however, instead of a traditional screen, a circular indicator is used, thanks to which the user can determine the direction of the detected object. And the features of this object (more precisely, the signal reflected from it) can be determined by the colour of the mark on the indicator: for example, a red mark corresponds to a strong signal, yellow to an average signal, green to a weak one. Another advantage of a flasher over a traditional fish finder is its high sensitivity, which allows you to follow even small baits. Thanks to all this, such devices are quite popular among anglers, however, they are not cheap.GPS module
The presence of a native
GPS satellite navigation module in a device with a chartplotter function (see “Type”). This module is responsible for determining the current geographic coordinates of the device and is thus a key element required for effective work with maps. At the same time, there are chartplotters that do not have this function — they are designed to connect an external GPS receiver.
Waypoints
The maximum number of individual waypoints that can be stored in the chartplotter's memory.
Waypoints can be used as a base for routing, as reference marks on a map, such a point can be set as an immediate destination, etc.; specific use cases depend on the instrument model. But anyway, the more waypoints you can simultaneously enter into the chartplotter's memory, the more convenient it is to work with them and the less often you have to clean this memory to make new marks.
Number of routes
The maximum number of tracks that can be stored in the chartplotter's memory at one time.
If you have to regularly travel on fixed routes, it is much more convenient to memorize these routes once and then select the desired option than to reprogram the navigator each time. Modern devices can store several tens or even hundreds of routes; the larger this number, the less often you have to free up memory for new routes.