Sunday, April 12, 2009

My Charting System

Final decision on charts, made my own charting system using Google Earth. I concentrated on the open water sections as smaller channels are well marked and navigation will be straightforward. My charts should work well for Kayaking because I only need general direction and don’t have to worry too much about water depth. Added benefit is they are printed on 8 ½ inch paper which I can just throw away when done, will have a backup of the graphics on my phone and iPod just in case. Try that with the $180 set of Nautical Maps.

Charts are made up of a series of reference points. Basic principal, as long as I have two known reference points I can figure out a compass headings. First, I choose a reference point in the distance then charted specific compass readings along my route path which show bearings to that reference point. I tried to stay with within 2km for my reference points and picked landmarks which should be easily distinguishable when I’m out on the water. I also included distance markers along the way so I can calculate km/hr in my head while I’m paddling to track progress, 1km = ~15 minutes.

Google Maps is amazing but unclear if compass readings are True North or Magnetic North. Either way I will have to adjust bearings out on the water due to annual/local deviations. I plan to first do this when I come out of the Port Severn Lock, Google Earth compass bearing from the Port Severn Lock to the tip of the main dock at Severn Boat Haven marina is 30 degrees. I will take a compass reading and then will have my variation, i.e. if it comes back 45 degrees then I know I have to adjust all bearings for +15 degree declination. I will continue to take similar adjustment calculations at various points along the way. I’m not crossing oceans with no horizon and my reference points are less than 2km away, being off +-5 degrees is not going to be a factor, will still get me to the general area. I will still have by BlackBerry which has GPS if I need it.

Each section of the Trent contains various maps, first I include an overview of the section I’m mapping so I can see the entire area. I include another overview of the section which includes major roads and highlighting which areas my detailed maps cover off, each sub-section is numbered with the associated detailed map. I then zoom down into a specific sub section of the map to get more detail, including minor roads and marked reference points, bearings and KM markers.

Posting the first section, Port Severn to Big Chute so that you have an idea of what I did. If interested in the full Trent Waterway set I created send me an email and I will send it along,

My Legend - HTML won't let me past the symbols
Compass Rose = Reference Point
Circle with a Cross = Compass Bearing to Reference Point
Boxed X = Distance Marker (km) from last marker

Click Maps to Zoom In

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