A couple of years ago, I worked briefly for an Internet company that was going to take over the world of sailing. By the time I bailed out, the company had nothing to do with sailing, and my job involved, among other things, surfing the Internet for links on eyeshadow. The company folded up soon thereafter, along with the other dot.coms. I look back on that period as my Rosemary Woods career interlude.
Before things got too weird, though, I learned a bit about digital charts and chartmaking-just enough to remain somewhat ignorant of the details of the technology, but still develop a strong opinion on the matter, and it is this: The US government chart rules supreme. There’s no substitute for it. It has the information you need as a mariner, nothing more, nothing less.
Digital charts fall into two categories, raster and vector. Raster charts are exact, equal versions of existing paper charts. Maptech has the exclusive right to produce and sell US government charts in that form. When you run a Maptech CD, or the information from it, you’re looking at a straight digital image of the NOAA/NOS chart on your screen. The limitation of raster images is that they can only operate in their own dimension: What you see is what you get.
Vector charts, on the other hand, are hand-made, with information from the paper charts in any profusion of detail that the vector cartographers care to include. The advantage of the vector chart is that information can be layered in what amounts to more than one dimension. If vector cartographers are picky about what they include and exclude in each layer, they can produce an image in which, for example, layer one shows the locations of some important buoys and a shoreline, layer two shows the locations of marinas in the area, layer three shows shopping opportunities, and layer four shows hospitals and churches-all occupying the same amount of resident memory in your machine as, say, a flat raster image showing a couple square miles of area, maybe unimportant area. Another difference is that in vector, you can zoom in and out and still see each layer in good resolution.
There could even be a vector chart that would look and feel exactly like its raster counterpart, but with all sorts of clickable layers-McDonalds and JiffyLube layers, for instance. No such thing exists quite yet, because it would take a huge amount of work, cost a lot of money to produce and buy, and then demand too much processing power and memory from the machine. You can rest assured, though-raster/vector hybrids will happen. All this stuff happens eventually.
Today’s vector charts are sometimes good and sometimes bad-it all depends on the skill of the people whose job it is to choose and plot the points in the vector layers. From what I’ve seen, most contain enough errors, either of judgment about what to include or exclude, or of position accuracy, to make them no better than a clever curiosity. If a programmer forgets to include an important aid to navigation, or misplaces it significantly, how are we supposed to know until we get there?
This month we have a review of five handheld GPS receivers that can download and display vector-type charts. As position-finders they’re all superb. As charting devices they’re pretty awful. What’s worse, they’re so bloated with functions that have little to do with navigating on the water that it’s often difficult just to dial up your latitude and longitude.
The reason is simple: sailors and other boaters are no longer the most lucrative market for GPS manufacturers. The software that runs on these handhelds is designed to cover the widest possible number of niche markets in as shallow a depth as the marketers can get away with, thus pleasing no niche completely.
Someday we’ll be able to see well-stitched, detailed raster images of specific sailing grounds on our handhelds, in color. I’m holding out until then.
-Doug Logan
