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Garmin gps; Entering coordinates
Topic Started: Jan 5 2016, 11:22 AM (1,109 Views)
Memphis metro


Murf 59
Jan 5 2016, 06:18 PM
aaronvincent
Jan 5 2016, 05:33 PM
People still use Garmins? Wooo, next they're going to tell me I can still fax :shit

I'm just messin' with ya. :lol Seriously though, don't all phones have some kind of navigational gps systems built in now? Mine has since 2010.
Not everyone has a cell phone.
I do not.
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myredvert
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myredvert

Cell phone or not, the gps function can't always be relied on when using it in remote locations away from the city. In my experience with my Samsung Murphy S6, it always seems to stop functioning when I am the least prepared otherwise for knowing exactly where I'm going.
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It is not that I do not believe you, it is that my gps does not believe you.
I believe that you believe me, but then either your GPS needs it's believer fixed, or maybe you need to open the manual and use the procedures in it to discover if/where you might be going wrong in the coordinate entry. ;) I know you have a computer, so I would imagine you could to download the applicable documentation from Garmin.

Sheesh, no wonder you have such a personal aversion to using actual cylinder/piston clearances and factory specs for a rebuild - just too damn many decimal places to get it figured out. ;)

Seriously, I do apologize for having a little fun with you on this one, but I couldn't resist. And I do hope you get it figured out. :thumb
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You are talking less than a meter difference if you leave of the 8th decimal point. If you are farther off than that... you have done something else wrong.
I used "feet" very loosely, because I didn't want to confuse the issue further by introducing the metric system, and the number was only borderline big enough to specify the measurement in "yards." :lol

Also, after considering that "a value in decimal degrees to 5 decimal places is precise to 1.1132 meter at the equator" must then be corrected for the reduction in the distance between each degree of longtitude as lattitude increases (based on the cosine of the degree of lattitude), the actual potential maximum error (in an east/west direction) is then reduced to roughly .865 meters from the equatorial standard of 1.1132. Now we're talking about roughly .86511888429389999835926666962512 meters or 2.83831655??? feet off if that last decimal place is missing. I apologize for my lack of precision, but the Bing conversion tool cut the number off. :O
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Memphis metro


Does this not look right?

Posted Image
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Metbob


Just put in the address, if it hasn't been updated in a while it will do that because it's going to get as close as possible. It doesn't see those roads.
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myredvert
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myredvert

You didn't round the last 5 up to a 6, that will get it at least a foot off. :lol j/k

Seriously? That entry looks perfect to me for what you posted for the coordinates of the parking area. :thumb :hmm

When you enter it in your GPS, does it let you zoom in on the destination to see if it's map correlates to what you see on Google Maps?

This isn't a discussion about the driving distances or route, is it? Just the location of the exact coordinates?

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Just put in the address,
Ummm, somehow I doubt this location HAS an "address," since it's in the middle of a very isoleted "wilderness" type area. He's driving to a dirt "parking area" that is roughly 60 feet across at best (depending on how many decimal places you use :lol ). If it had an address, I'm betting he would have started with that instead of coordinates.
Edited by myredvert, Jan 5 2016, 06:55 PM.
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cwatkin


I used to work for the USGS and still go GIS jobs. I wouldn't worry one bit about that last digit not being able to be input. You will be close enough.

Now I used to work with data provided to me in the WRONG COORDINATE SYSTEM like ALL THE TIME. I pretty much got to the point where I would go get some known good data of the same area and then overlay the new data on top of it. You would be amazed at how many times it would be off by 50 miles or more! This was data being provided by governmental agencies and engineering firms. They weren't using this data on a wide scale so on a local level everything seemed correct. The problems became very apparent when trying to enter it into a bigger database.

Then there is the issue of using a UTM system which defines linear units in meters except it would be in US Feet instead. That was another common one, often combined with the issue I described above. Obviously scaling errors would be very obvious when using the wrong units. There are no rules saying this can't be done and it is fine as long as this information is included in the spatial reference files and metadata. This just isn't the way it is ever done though.

Conor
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cwatkin


Then there is the difference between US Feet and International Feet. No, a foot is not a foot and it comes in different forms. You can pretty much correctly assume that any "feet" units in GIS are US Feet and not the international foot. These two are just a TINY bit different so that is more likely to cause problems because they can be close enough and sneak by where having something in the wrong coordinate system or meters instead of feet is going to be glaring.

If you want to read up on why the measure of a foot might not be the same, read this: http://www.pobonline.com/articles/91189-from-the-ground-up-the-international-versus-u-s-survey-foot

Odds are any data you come across will be in US Survey feet. I never came across any datasets that were in international feet but they might have been and the error was too small to be anything of concern.

Conor
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mt999999
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Self-Declared "Genious"

Murf 59
Jan 5 2016, 06:18 PM
aaronvincent
Jan 5 2016, 05:33 PM
People still use Garmins? Wooo, next they're going to tell me I can still fax :shit

I'm just messin' with ya. :lol Seriously though, don't all phones have some kind of navigational gps systems built in now? Mine has since 2010.
Not everyone has a cell phone.
Or their cell phone is an old-as-dirt brick like mine... :lol

Navigational systems were not a feature when my phone was manufactured. Then again, neither was mobile internet. Or 3G networks... :lol

I still have a Garmin GPS. Even if I had a fancy phone with a GPS built in, I think it's a lot more dangerous to mess around with than a simple suction cup windshield GPS holder.
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Memphis metro


myredvert
Jan 5 2016, 06:50 PM


When you enter it in your GPS, does it let you zoom in on the destination to see if it's map correlates to what you see on Google Maps?
I reentered it and for some reason it appears to be pretty close. Atleast going by the amount of time it should take to get there. I do not see the mileage like I did the first time but only the amount of time to get there. It really does not show the destination on the map that well to tell where it is. Will just have to drive it and see what happens.
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