[Rockhounds] more thoughts on sharing collecting sites

[DonH]

Tim Fisher wrote:

>  And why would you need UTM if you have
> +/- a couple foot accuracy using WGS84 with a good GPS unit? Inquiring 
> minds want to know...I can't recall the last time I saw UTM coords in a 
> geology or paleontology pub, BTW. 


Hi,

That's what Lanny says too... however it is easier to make measurements, 
when necessary, because a meter is a meter is a meter... as longitude 
lines converge toward the poles, the absolute distance between 
coordinates changes.  I find the deg/min/sec notation easy to misread, 
though I admit some folks say that about UTM as well.  But UTM coords 
are a simple string of numbers.  They are easy to store in a spreadsheet 
and manipulate in numeric order.  In fact, when I visited the Idaho 
Geological Survey office to show the geologist all the places I'd been, 
he told me to bring the UTM coordinates as columns in a spreadsheet. 
Within seconds he had it all imported into his program.  He said that 
would have been more difficult with lat/long.

I put GPS systems to a real test in the last few years, finding obscure 
localities with dubious maps.  With UTM, it is much easier (in my 
experience) to realize how far you are from where you are trying to be 
in real meters, without needing to convert.  Using a scale rule, you can 
do some measurements on a map if you need to.

Like many things, it is a matter of taste and usage.  I grew up using 
lat/long in the Boy Scouts and Civil Air Patrol, just like everyone 
else.  But once I went UTM, I never found a reason to go back.

BTW, the UTM coords will be in my thesis, along with the datum of course.

But again (to the lurking readers) the most important point is to learn 
to use your GPS properly, be consistent with your datum, and record as 
much info as you can!  You never know when it will be useful.


best,
Don