Navigation Part 2 -- Preparation

Sherwood Botsford

Navigation -- Maps and Map Prep

Earlier I gave you some hints on evaluating routes.  In this article I'll talk about some map prep work that will make your life on the way easier.

I'm starting by assuming that you are traveling in Canada.  Some of these tips will change somewhat if you are using different maps.

Most of Canada has been mapped at 1:50,000.  This is 1 km in the world = 2 cm on the map.  For anything but really big lakes, this is my preference.

Once you have a rough route you need a list of maps.  I have gone to the library at the U of Alberta and used their set of NTS maps.  I'm guessing that most large academic  libraries have similar collections.

Pull the maps for your route.  Lay out the entire route.  Trace it from end to end.  Gotcha:  Verify that the adjacent map really is adjacent.  I had a case once where a river wandered off the east edge at the same distance from the top, as it started on the west edge.  When putting the map set together I went AC instead of ABC.  Fortunately I caught it in time.

This is your check to see if the route is reasonable.  Make a list of the maps you need.  I advise writing both the number 87 G/14 and the name, Boundary Lakes of each map, as it gives you some fail safe when ordering maps.

There are companies that supply scanned images of maps.  Using these in conjunction with OziExplorer works quite well.  This is certainly cheaper, but I will point out some gotchas:

*  Most colour printer ink runs when wet.
*  You are working on smaller pieces of paper when you print.  This either means smaller scale, or more pieces.
*  It's not enough to see your route.  You need to see enough of what's around you to keep oriented.    E.g.  If you get on a side channel (upper Mirror river…) you want to have a wide enough strip around your route that you can recognize where you are on the side channel.  I generally like to have 5-10 kilometres on either side of my route.  This will encompass the hills on either side of the river valley.  On lakes I want either the entire lake, or the shore I'm traveling out to where there are no more islands.  On large lakes, such as La Ronge or Cree Lake, I'll do my route at  two scales -- the regular 1:50,000 and a reduced scale (more world per map) Usually 1:100,000.  An alternative is to carry the 1:250,000 (10 km = 5 cm) maps for the large lakes.

One cheat:  Every trip has a couple spots where you cut across a corner of a map I often photocopied the map at the library or printed that corner form the CD and taped it in place at the start of the new map.  (A photocopy is on weak paper.  By putting at the start, you use it while the map is fresh and dry)

Our safety rules at SJ required that we carry two sets of maps.  One set had to be 'real' NTS published maps.  The backup set could be printouts from the maps on CD, or could be good photocopies.  The two sets had to be in different packs. (Yes we learned this the hard way.)

"What about GPS?"

GPS has it's place, but I don't rely on it.
1.  The maps are crude, and you don't have a big enough window to deviate from your programmed route.
2.  Maps don't require batteries, and they don't break when dropped on rocks.  On the otherhand your GPS won't blow away in the wind.
3.  GPS don't swim will.  Maps will float.

Advantages of a GPS:
1.  On routes where every shore looks like every other shore, a GPS will locate you.  This means you can daydream at the back of the boat, instead of watching your maps.
2.  When you find a surprise on the river you can pinpoint it exactly.  This makes your error letter to NTS much more plausible.  Do make sure that your GPS and your map are using the same grid.  (Canadian maps use NAD27.  GPS usually default to WDG84.  At St. John's school confusing these will cause a 220 meter error.

I've done trips using the real maps as primaries and the CD maps as backups, and vice versa.  When you are on route, it's a wash.  When you get off route, be it for a mistake, or because of a forest fire, you want the bigger maps.

Once I have my map set, I number them, and highlight the route with a pink highlighter pen.  Yellow is too light.  Green and blue are too dark.  The maps are numbered on the upper right  corner, and on both ends of the route path.  If a map is used twice, it gets TWO numbers.  Where it goes off the map there is an arrow, and the number of the next map.  Where it comes onto the map is an arrow pointing toward the pink line.

Stack the maps in order first on top.

Using a drawing compass, set it carefully to the grid scale of the map.  2 cm for most maps, but if you print them yourself, adjust to be one grid square.

From the start, set the point, and draw a short arc along your route.  Set the point on the arc, draw another arc, another km down the route.  When you are on narrow river, draw two arcs on either side.  do NOT draw on the river, as the mark can be confused with a 'rapids' bar.  On the lakes you don't have to be as careful.

Every 5th mark, write down the number of kilometres from the start 5 10, 15. …

Do the first draft in pencil.  Then go over it with red fine point permanent fibre micropigment pen.

This gives you a map that is easy to read when you are in the back of a bouncing canoe.  It also makes logbook notes easy.  "Unmarked class V falls at km 265.5  Portage on Right)"

You can trim your maps if you wish.  It makes a significant difference when you have 30 maps in your pack.  Don't get too enthusiastic.  I once trimmed the maps so close that I no longer had the numbers saying which map it was, nor the name, nor the magnetic declination.  This makes them hard to sort.  I will generally trim off the legend off most of the maps. (Leave it on map one as a reference.) and I'll take most of the scale info off the bottom, but leave the name.

You can also laminate your maps.  You don't have to keep them in a pouch this way, but they are hard to write on and they take up about 6 times the volume in your pack.

Next each map is folded in 9ths.  Why 9th?  Because 9ths will fit in a standard 1 foot zip lock bag with room.  I will pack 4-6 maps per zip lock bag -- whatever is not stuffed.  Zip the bag almost shut, then put two heavy duty rubber bands each way on the bundle, and finish zipping.  They are always folded so that the start of the map shows.

Next:  Navigation in the field.