Glacier Bay Ice Grand Pacific Glacier Glacier up Close 2,200 Harbor Seals
For additional pictures, see (HERE)
For Examples of Garmin USA Topo, BlueChart, Magellan Topo USA, and USGS DRG Maps, see (HERE)
Street Atlas 8 Map
This was a cruise from Juneau to Glacier Bay
to Tracy Arm and down through the Inland Passage of British
Columbia, Canada, to Seattle. In order to make a 24-hour-a-day recording of the ship's travel, we used a G-III+ with an active GA-26 antenna suction-mounted to the cabin window. It was powered by the ships electrical wall jack using a 115vac-to-12vdc converter. For reference, the G-III+ was loaded with the R&R maps of the Alaska portion of the trip. As far as could be estimated, it had lock-on about 99% of the time for the trip.
The GPS trackloging was set 100 feet in the Resolution mode. As the memory approached 100%, the tracklog was saved 10 times for the 10-day trip. There are a few gaps where the GPS filled the track memory and the "tracker" was asleep(!), but they aren't due to loss of lock. Glacier Bay is in the upper left-hand part of the above map.
Glacier Bay Tracks with MapSource USA Topo Map
City of Sitka with MapSource Roads & Recreation Map
Four different sets of Garmin MapSource maps were used on the trip. For a "walking around" GPS, we used an eMap and three 8MB Carts pre-loaded with USA Topo maps of the Alaska portion, Canada Enhanced Basemap for B.C. Inland Passage, and MetroGuide for Seattle. eMap lock on deck was possible about 90% of the time, and in the cabin window about 75% of the time. A MapSource *.mps file of the whole trip plus waypoints created is located (HERE). With this file, and a map of your choice (by loading the track into a Garmin GPS), you can check the accuracy of the GPS/map combination. The waypoints are more or less self-explanatory, but they will have to wait for a fuller report on our website.
Inland Passage of British Columbia with MapSource Canada Enhanced Basemap
We were impressed by the quality of the Canada Enhanced Basemap in the Inland Passage. The coastline and nav-aids seemed remarkably correct -even at high zoom levels. Of the 100 or so navigation markers we passed, there were at most one or two that had been moved from that shown on the map. (And the tracks don't show us running over any buoys or up on the the beach!).
The waypoint Ripple Rock is at a VERY narrow point in the passage where before the 1950s over 120 ships and 114 lives were lost due to a submerged rock in the middle of the channel. In 1958 Dupont completely filled a drilled tunnel under and up into the rock formation with dynamite. When the blast went off, it was the largest non-nuclear explosion up to that time! -And it also got rid of the rock.
City of Juneau with MapSource Roads & Recreation Map
We were somewhat disappointed in the accuracy of the R&R, MetroGuide, and USA Topo street maps in Alaska. (This had also been reported on the News Group by Chuong before we left). In Juneau, where the streets run at a 45° angle, the GPS was generally off by one whole street due to the GPS tracks being about 200 feet north of the map streets.
So, to document this I got out in the middle
of three intersections in three cities and recorded three waypoints!
The waypoint, FRONTFRANK, was recorded at the intersection of Front St. and Franklin St. in Juneau, and is north of the map intersection by about 200'. In Ketchikan I recorded MILLBAWDEN at the intersection of Mill St. and Bawden St. where the waypoint was also north of the intersection, but only by about 100'. Then in Sitka I recorded AMER-LINCN at the intersection of American St. and Lincoln St., but this time the waypoint was SOUTH of the intersection by about 260'.
We checked R&R, MetroGuide, and USA Topo maps, and all had the same errors. Street Atlas 7 and 8 also have these errors, which leads one to believe that the street databases come from the Tiger maps...??? (So, there isn't much that can done about the map accuracy).
Street Atlas Plot of continuous GPS track recording. Blue=Ship Red=Airline
One has to admit, "GPSing" on a ship is lots of fun, and you're sort of a celebrity to the other passengers who wonder where they are!
(C) Jack Yeazel