Sunday, April 05, 2009

Navigating in the Orinoco Delta

I've always found navigation an interesting topic, and my friend Tristan's Natural Navigation course was a fantastic way of getting an overview of the subject. So it was, er, natural (groan, sorry about that) to think about it when travelling in those tropical latitudes.

To me felt that a different approach was needed than we use at higher latitudes because the geometry involved means the south/north methods don’t work so well. For example take the sun: up here at 50 ish North the best navigational information comes around mid day when the sun is due south (and vice versa in Australia). Morning and afternoon are a bit vaguer as have to guess how much south/north of east/west the sun sets, which depends upon date in the year, latitude, horizon angles etc.

However in Caracas there was minimal navigational information around noon as the sun at this time of year was pretty much overhead. Even with a stick that is exactly vertical it would be very hard to work out when the shadow was at a minimum. However in the morning / afternoon it was easier to gain navigational information as the sun is pretty close to due east/west. In addition of course its rather hot in the middle of the day!

Similarly at night. While up here we can see the stars going “round” the pole star, in the tropics it feels more like a conveyor belt (though I’d guess the locals would call it a flowing river) going from east to west. I think I did spot the pole star for a flash but at 9 ish degrees north it isn’t that easy unless in the middle of a channel on a clear night. The constellations also look different: we see Orion as being “upright” but overhead unless you orientate your head just right it appears at an angle.

Anyhow that’s what was going through my mind and had this whole theory about east/west being more important to people there than north/south which feel are the most important to us up here. However this could just be bunkum and my ignorance, in particular as you will see it wasn’t backed up by evidence.

I tried to find out how the Warao people who live in the delta navigate and as I speak no Spanish and they no English (they have their own language and actually not all of them speak Spanish) I had to use our Venezuelan guide as a translator. However English was her fourth language after Spanish, Italian and German and she was pretty tired at this point so could have completely missed the point.

Anyway I asked her to ask them how they navigate: did they use the sun and stars and if so how? The answer I got back (again take into account the layers of translation involved) was that they don’t. What they do is keep very good track of where they are in the tide cycle. The Delta has a 2m ish range between high/low waters, and so from that and the direction of current (which is easy to spot as there are these plants that drift around on it) they can work out which is towards the sea and which upriver. This is their main navigational tool, and when on an island they use blazes and “their nose” (not sure if that’s literal or means sense of direction) to find their way to the nearest water and then use water flow direction.

That would make some sense, but would result in a topological map not a cartographic, which actually would be more useful. Even with knowing the sun was east/west I found the many curves and bends of the river disconcerting but in terms of getting from A -> B irrelevant: what matters is the channel and whether you are going up it or down it.

Its a bit like the London tube map: what matters are the lines and interconnections (nodes).

Though the tube doesn't have obstacles in it like the sunk ship above, and the Orinoco River doesn't close for engineering works at weekends!

3 comments:

Greg and Kris said...

I moved about the U.S. growing up and had mountains to orient myself the first eleven years; at one point, moved from Salt Lake City to Colorado Springs and I only had to recall that the mountains were now to the West, where they had been to the East.

Then my parents took us to Texas and Mississippi. Texas was a new experience, because there was no landmark taller than everything about us. I had to learn the sort of topographic navigation that you describe here. Big mountains act almost like a celestial guide.

I'm always curious how folks find their way around. Most interesting to me is how women do it, since it seems to be so completely different than men.

JP said...

Caracas was a bit like that with mountains to the north and south and the city spreading east and west.

As a useful final piece of navigation information the mountain to the north is the one with the cable car going up it!

Of course in the mall I used another un-natural navigational technique when learnt that its the passage by the cell phone store with the iPhone in it that led back to my hotel :)

Carol Anne said...

My navigation is almost purely celestial/solar -- but then, I'm in a part of the world where the sky is visible most of the time. Mostly, I just simply know where I'm going ... typically, if I've been to a place under my own power/control once, I can find my way back from it and to it again.

I was, however, completly at a loss one time when I flew in to La Guardia and was driven in a limo to a conference in upstate New York. For nearly the whole week, it was heavy overcast, and my instincts were useless. I was utterly disoriented at the end of the week when the sun came out and the directon I had thought/felt/KNEW was east turned out to be south!

Worse, this was a Girl Scout conference ...