Adding distance to GPS coordinates?

[+Len & Cheri]

I'm trying to figure out how to add distance (meters) to GPS coordinates. Yes, it's for a puzzle cache and no I'm not asking you to solve it for me I have been all over the internet trying to find out how to do it and have had no luck. I can add the meters by using the ruler in Google Earth, but the results have been less than precise. Anyone know of a good site that explains how to do this?

[+Corey]

Are you trying to create a waypoint at a given distance/bearing from another (a "projected waypoint")? Many GPSr's and software applications have a function to do this.

[John E Cache]

I'm trying to figure out how to add distance (meters) to GPS coordinates. Yes, it's for a puzzle cache and no I'm not asking you to solve it for me I have been all over the internet trying to find out how to do it and have had no luck. I can add the meters by using the ruler in Google Earth, but the results have been less than precise. Anyone know of a good site that explains how to do this?

Hint: UTM

[+Blaidd-Drwg]

2nd hint: Pythagorean theorem

[+Len & Cheri]

Are you trying to create a waypoint at a given distance/bearing from another (a "projected waypoint")? Many GPSr's and software applications have a function to do this.

 

Yes, I need to add a specified number of meters to the given coordinates (west and south). I didn't want to get to specific, but here is the cache: GCWHDM. Being a noob, I'm still learning things as I go along. So far I have tried Google Earth, Mapsource and EasyGPS and none really give me precise enough coordinates. At least not the way I'm fumbling around with them

 

It hasn't been found since 2 Jan 07, so either I'm not the only person who can't figure it out, or the cache isn't there anyway.

 

Thanks! I will look closer at UTM and Pythagorean theorem.

[timz2]

What accuracy do you need, at what distance from the origin?

 

If nothing else, the online calculator at the NGS site will give you whatever precision you need, as long as it's not better than a millimeter. (And as long as you know the direction/distance that precisely.)(And as long as your height above sea level isn't enough to throw things off.)

 

http://www.ngs.noaa.gov/cgi-bin/Inv_Fwd/forward2.prl

Edited December 15, 2008 by timz2

[John E Cache]

Thanks! I will look closer at UTM and Pythagorean theorem.

You're welcome. I suppose I should give credit to Danman and his picture perfect cache.

[+PDOP's]

You could also use FizzyCalc

[+Map Monkey]

2nd hint: Pythagorean theorem

Hint misleading and not needed.

 

All the information on the cache page is shown clearly for you to find GZ without trouble or using fancy calculators.

 

mm

[+GerIRL]

You can use GSAK to project a waypoint by a bearing and distance. It will create a child waypoint with the new coordinates. Right click on the waypoint in the listing and one of your options is to "project". I get N30° 52.502 W83° 17.267 for the final.

Edited December 15, 2008 by GerIRL

[GeoBobC]

Depending on the GPS unit, you can also do this on the GPS itself. On a Garmin 60C series GPS, for example, you can project a waypoint from a known starting location. The projection includes a distance and bearing from the starting location. The distance can be in meters if you prefer.

[savant9]

Although the cache page doesn't specify, I would assume the directions given are for "True" and not "Mag".

 

The -5 deg difference between true and mag at the cache site with over a 2 km projection would make for a pretty large error (~190meters)

[+GerIRL]

I would also assume a TRUE bearing, especially as magnetic bearings change from year to year.

[John E Cache]

I can't take it anymore. The answer to "'... trying to figure out how to add distance (meters) to GPS coordinates." is switch your GPS to UTM. The UTM coordinate are partly XY position in meters. Simply add or subtract to move a certain amount of meters E/W and N/S. The "to" in the question is "to" literally add meter numbers as part of the actual coordinate.

[+Map Monkey]

LOL, i had the willpower to hold off telling them.

 

Some people just make something so simple, so hard.....

 

mmm

[+GerIRL]

As they say - there's more than one way to cook an egg!

 

It took me literally about one minute to click on the GPX link, wait for GSAK to open, then right click on the waypoint and enter the bearing/distance, twice. Probably faster than to change your units to UTM, and then do the 2 calc's.

[John E Cache]

As they say - there's more than one way to cook an egg!

 

It took me literally about one minute to click on the GPX link, wait for GSAK to open, then right click on the waypoint and enter the bearing/distance, twice. Probably faster than to change your units to UTM, and then do the 2 calc's.

OOPs sorry no offense intended. I did the UTM trick half way through a cache find and I had no mouse in my pocket to right click. I did have a calculator so I did a rectangular to polar conversion to make a normal GPS projection. The UTM projection and the normal projection made the same waypoints. As you can see, I am in no hurry when I cache. Now that I think about it I may go back and try an east normal projection and then do a north projection from the intermediate point. BTW I like my eggs over easy.

[timz2]

Some people just make something so simple, so hard...

Yes, life is simpler when you ignore the unsimple stuff. I still don't know what distance and accuracy the original poster is hoping for; is the difference between grid north and true north irrelevant to him?

Edited December 16, 2008 by timz2

[+Prime Suspect]

I'm trying to figure out how to add distance (meters) to GPS coordinates. Yes, it's for a puzzle cache and no I'm not asking you to solve it for me I have been all over the internet trying to find out how to do it and have had no luck. I can add the meters by using the ruler in Google Earth, but the results have been less than precise. Anyone know of a good site that explains how to do this?

I Googled this in 15 seconds (by Googling coordinate distance). Your tax dollars at work - might as well make use of it.

[timz2]

Looks like that uses a spherical earth.

[+fizzymagic]

I can't take it anymore. The answer to "'... trying to figure out how to add distance (meters) to GPS coordinates." is switch your GPS to UTM. The UTM coordinate are partly XY position in meters. Simply add or subtract to move a certain amount of meters E/W and N/S. The "to" in the question is "to" literally add meter numbers as part of the actual coordinate.

Except for the obvious problem that UTM northing is not north, and UTM easting is not east.

 

To solve a puzzle it would probably work, but to create a puzzle it would be Just Plain Wrong.

[+Okiebryan]

I thought we weren't supposed to solve puzzles for others here in the forums. If that was my cache, I'd be PISSED. And I don't mean the fun drunk kind of pissed like in England, either.

[+Len & Cheri]

Sorry it's been so long since I posted, I've been crazy busy with Christmas shopping and all. I want to thank everyone who provided valuable clues on figuring out how to do this. I checked most of them out and the one that I liked the best (and was easiest for a noob) was using GSAK to project a waypoint. I did look at GSAK before, but it's really, really overwhelming when you first start using it with all it's options and don't know what you're doing.

 

Dang, I just took a look at Fizzycalc and I wish I would have tried that first. That is a very simple and straight forward program, much easier than using GSAK. Of course GSAK does a ton more stuff.

 

I haven't went and checked it out in person, but I'm still not confident that it's there. It's been a long time since it was found. Although, I did find one by the same owner that had went unfound for over 2 years, so maybe I'll get lucky and it's still there.

 

I have a Legend HCx and as far as I can tell it won't project a waypoint. It may, but the documentation that Garmin supplies with it is so sorry that I don't know how half the items on it work. I did figure out how to switch it to UTM, but am unclear on adding and subtracting from the UTM coordinate. Surely it's not as easy as subtracting (or adding) the desired distance in meters from the 7 digit UTM coordinate, is it?

 

Anyway, thanks again for helping this noob

[+Prime Suspect]

Looks like that uses a spherical earth.

The OP is adding a relatively short distance (measured in meters, not kilometers). The difference caused by using a spherical earth isn't significant.

[+Len & Cheri]

Prime Suspect, in the link you provided you add the coordinates in the Latitude and Longitude blocks, but it only allows 2 digits in each block, but the coordinates have 3 digits in the last string of numbers. What am I missing? How should the numbers be entered?

[+Cardinal Red]

Prime Suspect, in the link you provided you add the coordinates in the Latitude and Longitude blocks, but it only allows 2 digits in each block, but the coordinates have 3 digits in the last string of numbers. What am I missing? How should the numbers be entered?

 

The site linked to by Prime Suspect is in the Format DD MM SS (Degrees, Minutes, Seconds).

The Geocaching standard is in Format DD MM.mmm (Degrees Minutes, Decimal Minutes).

 

Seconds divided by 60 = Decimal Minutes

 

Decimal Minutes times 60 = Seconds

[timz2]

The difference caused by using a spherical earth isn't significant.

Sure-- but no reason to bookmark that calculator when the accurate calculators are just as easy to use. Maybe someday they'll want accuracy.

[+Prime Suspect]

The difference caused by using a spherical earth isn't significant.

Sure-- but no reason to bookmark that calculator when the accurate calculators are just as easy to use. Maybe someday they'll want accuracy.

The point I was making was that there are any number of calculators available on the web with a few seconds of searching.

[+Len & Cheri]

Thanks Cardinal Red! I appreciate the help.