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UTM or Lat/Long

Started by wiiawiwb, May 29, 2012, 08:21:46 PM

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wiiawiwb

Hi folks.  I recently got an eTrex30 and love it.  I've been able to use BaseCamp and that's great.

Most of the people polled in my hiking club have their GPS unit and mapping software set to UTM rather than Lat/Long.

Question - Which position grid do you folks suggest? I live in the Northeast part of the US if that makes any difference.

babj615

Where you live makes no difference.

You will see a lot of people say one is better than the other, while others will swear the exact opposite.

The most common is still Lat/Lon, but UTM is growing in popularity.

Do you ever do math in your head? Which is easier for you, the US fractional system, or the world standard metric system?

The fractional system is base 4, or 8, or 16, or 32, depending on the resolution detail desired. I have a hard time doing simple math with fractions in my head, and, frankly, I can not for the life of me figure out why the system was ever created in the first place.

The metric system is base 10, no matter how many place you need before or after the decimal, and basic mathematical process are frankly quite simple using this system. Quite often, it is as simple as moving the decimal. The metric system is based purely on science, and never changes.

So, getting back on topic....

Do this simple test:

Set your GPS on UTM, go outside in clear view of the sky, and let your position stabilize.

The two long sets of digits are your position (within your grid) in meters.

The first number is your distance(meters) East in the grid, and the second number is your distance(meters) North in the grid.

Take a full step North, and you will see the second number increase by one.
Take a full step East, and the first number will increase by one.

The numbers decrease by one in the opposite directions.

Now, if you have your position in UTM, and a target destination or waypoint in UTM, you can do some pretty simple math in your head and know, looking at the NUMBERS ONLY, exactly what direction the target is from you location, and within a meter or two just how far away the target is. Without even using a compass.

If you have enough space, make a waypoint in one corner of your yard, or down the street, and then see for yourself.

THEN....

Try all this using Lat/Lon.

You can decide for yourself which is easier for you.

Oh, and one of the first arguments you will hear about this is that changing from Lat/Lon to UTM can not make the GPS any more accurate, and that is absolutely correct.

But, it CAN make it more precise.

Look at a tape measure with both inches and centimeters on it. Which has more marks, more closely spaced?

Which do you think has better resolution, and therefore better precision?

Garmin GPSMap 60cs, Dakota 20, Colorado 400t, Oregon 300/400t/450/550t/650/650t, Montana 650, Lowrance Endura Sierra, nuvi 3790, iPhone 3G/4/4s
Geocaching ID: Atlas Cached
OpenCaching.com Ambassador

Indrid Cold

Quote from: wiiawiwb on May 29, 2012, 08:21:46 PM
Question - Which position grid do you folks suggest? I live in the Northeast part of the US if that makes any difference.
Be the first in your club to use USNG, all the kids are doing it :P

babj615

Indrid, how is that any different than the UTM system?

The wiki is a STUB, with very little info, but from what I can see, it is nearly identical to UTM in function and execution.
Garmin GPSMap 60cs, Dakota 20, Colorado 400t, Oregon 300/400t/450/550t/650/650t, Montana 650, Lowrance Endura Sierra, nuvi 3790, iPhone 3G/4/4s
Geocaching ID: Atlas Cached
OpenCaching.com Ambassador

maps4gps

I do not know if this is the same person; however, someone was trying to get house addresses replaced by a grid 2-3 decades ago.