The Garmin Vista GPS

The GPS

   The Garmin Vista GPS is designed for active, outdoor use, e.g., by cyclists, hikers, canoeists, etc. It is waterproof and you can get a substitute backplate designed to fit onto a matching handlebar bracket (if you can keep it from interfering with your bar bag). It was perfectly positioned for reading the display and for using its buttons to access its multiple modes.

   It has most of the functions of a cycle computer: elapsed time and distance for the current leg and for the entire trip separately, current and average speed for the leg and trip, etc.

   In addition, it gives total ascent for the leg and trip as it has a built-in pressure altimeter. (It can also tell altitude using the GPS function, but this is not very accurate, typically only within a couple hundred feet.). I compared its readings with my bike's computer and with my Avocet altimeter/wristwatch, and the GPS acquited itself very well. I came to trust it above the other two.

   Of course, it will also do those things that only a GPS will do: give straightline distance to the next waypoint, time to the next waypoint, straightline distance from home or to Duncansby Head, or whatever point you choose.

   You can easily cycle through its several pages. They are: a moving map that shows your position and direction of motion (plus speed, time, distance and time to next waypoint, or other selectable readouts); a compass rose with your heading at the top (and again other selectable read-outs); a graph of altitude vs. time or distance; a page summarizing trip and leg data; a page showing which satellites are being received; and a page to specify whether you want distance in miles or km, whether you want the GPS to record your track; find out when sunrise/sunset and moonrise/moonset are on the current day; and many other things.

   Of all the gadgets in the world, this is the best. By far.


Entering Waypoints and Routes Into the GPS

Waypoints are a series of points along the route spaced closely enough that straight lines connecting them will trace the actual route. I used 600 waypoints for an average point-to-point separation of about two miles.

My Garmin Vista had 24 meg of memory. Having just bought it, I had never actually programmed in waypoints or routes or any of that. Nor had I used it to follow a route. I spent a lot of time programming in waypoints based on faith that the system would work.

The pretty good GPS manual did not answer my two main questions. I knew that you could ask the GPS to "GoTo" a waypoint and it would tell you the distance, direction, and time to get there. A small arrow would point toward the waypoint relative to your direction of motion. For example, if the waypoint was straight ahead in your direction of travel, the arrow would point straight ahead, i.e., toward the top of the display. One of my questions was: Would the waypoint change automatically to the next one as you reached each waypoint? I hoped so because that would mean that the arrow would point the direction to turn (or not to turn) at each waypoint. I had included as waypoints all intersections that required a turn (and many that didn't) hoping that the arrow would sutomatically point the way and I would not go flying past a turn.

Even more important was the overriding question of whether the waypoints were accurately entered. There are two ways to enter the waypoints: the difficult, approximate way and the easy, accurate way. The hard way is to decide on a waypoint, read its coordinates off of a map - not easy and not accurate - then enter the coordinates and waypoint name into the GPS by hand. I did it this way for only one waypoint so I know that it is both time-consuming and less accurate than Plan B.

Plan B, the easier way, uses a program that takes the drudgery out of the process. I used the program, MacGPS, written by Lawrence James of Nederland, Colorado (the town with the frozen Norwegian) on my Mactintosh. It is a wonderful program that has been improved frequently, often at the request of users. He sends free updates for over a year.

To create waypoints, you first scan a map that includes your route. Then, you calibrate it by clicking on several points of known coordinates, i.e., where two coordinate lines cross. Now, by interpolation the program knows the coordinates of any point on the map so if you click on a spot that you want to be a waypoint, the program computes the coordinates. It also allows you to name the waypoint which is a lot easier on the computer keyboard than entering directly into the GPS.

The challenge is to come up with 600 different names for waypoints since the Garmin does not allow duplicate names. I divided the trip up into 16 "routes," guessing at each day's ride, supposing it would take 16 days. I was one day off but no matter. By appending a suffix 12A or 12B, etc., for the 12th route, I could easily give different pubs (or whatever) unique names, PUB-6A and PUB-9A, or PUB-6A and PUB-6B for example.

The only problem with this scheme was that, although the Garmin Vista's specs say that it will hold up to 20 routes with 50 waypoints per route - for an apparent total of 1000 waypoints - it will actually hold only 500 total. I learned this after creating 600 waypoints when it was only a few days before I was to leave. I had neither the time nor inclination to go back and eliminate 100 waypoints. I decided to take the last 100 on a ZIP disk along with the MacGPS program and cables to upload those waypoints after finishing with the first few routes. I would simply have to find a Mac, which ought to be duck soup in Scotland, right?

The first thing you learn from using the program is that there are far more coordinate systems in use than the three that Mrs. Witherspoon taught you in third grade. The British ordance survey atlas that I used employed the "British Grid System," which is tailored to fit the British Isles. I had to figure out how the system worked and had concerns over whether I had properly specified that system within the program. MacGPS tells you something about some of the systems, but not a lot about all of them. Lawence James had to know all of the fine points when he was writing the translations between the various coordinate systems and lat-long, but those details are not in the documentation and in answsering an enquiry of mine he indicated that he had forgotten the details. So I puzzled it out and did what seemed right.

I was encouraged when, after entering the various route and waypoints, they superimposed themselves nicely on the scanned maps when both were shown on the computer screen. Not a difficult hurdle - there could still be serious problems - but a satisfying one.

The second test was to "move to" the SW tip of England using the GPS display. The coast of the island is shown in rough detail built into the mapping software of the GPS. The question was whether my waypoints would lie along the coast of Cornwall as they should. It was mildly disconcerting that some of them seemed to stray off-shore. I told myself that this must be because the coastline Is not accurately depicted by the GPS.

This remained a concern until I actually tried it out at Lands End.