posted 05-07-2009 11:59 PM ET (US)            

http://www.local798.org/

The other is a chart plotter and SONAR with internal GPS antenna.

http://store.humminbird.com/humminbird-products/sonar-gps-combos/ 700-series/798ci-si-combo/prod407450-1.html

Maps are useful on highways. You probably need charts for your boat. Most electronic chart plotters need electronic charts to be useful. Marine charts are now available in an electronic form. There are many publishers of these charts. Generally when you purchase a particular brand and model of electronic chart plotter you will also be buying into a particular format of electronic charts. Before you select an electronic chart plotter, be certain that the electronic charts available with it are useful for your purpose.

The topic of digital chart cartography is itself so vast that I do not believe there is any really good comprehensive discussion, summary, or article which deals with all of the many brands and formats available and makes an organized and thoughtful comparison of them. In general you find there are only anecdotal reports about particular charts and the chart plotters that use them. Making any comparison more difficult, each brand of electronic chart cartography usually has multiple tiers of product with various features and complexities. While I have tried to keep abreast of this myself, I find that I really have not been able to develop more than a cursory understanding of what chart features each brand has, and I have no real idea of how they compare. You are welcome to begin your own study.

When you ask if a particular unspecified package of charts is worth $150, you have asked an impossible question. First, we have no idea what charts you are talking about. Even if we knew precisely what chart package you were asking about, it is difficult to assess the worth or give them a value relative to other offerings by other manufacturers. Because we have no idea what area of the world you plan to use these charts, we cannot know if they are suitable, even if we knew what charts you were talking about. Some charts are enhanced with details of bottom structure to enhance their value to anglers. Some charts give details of small inland lakes and rivers; others do not.

All of my qualifications notwithstanding, I suspect that for $150 you will get more charts than you could ever want, and far more than you could ever purchase in a printed paper format for that price. So, yes, they are worth it.