Bum coordinate translation

[raybonz]

This is driving me crazy. When I find a cache I want to visit I convert the coordinates to decimal so I can load them into my Garmin Streetpilot i3. I am using JEEEP.com translation and for some reason the coords it gives me puts me way off course. Today I tried doing this and my i3 had me 12 miles off course when I arrived at destination!! This doesn't make any sense to me. I tried both map datums(NAD27&83) and same results both times. The GPS is fine and I am copying and pasting plus dbl. checking and all data is entered correctly into the poi file I'm creating yet it throws me WAY off. Does someone have a better way to translate deg.\min.\sec. to decimal ? I have absolutely no problem getting decimal coords from addresses ONLY the conversion problem. My handheld is no good for navigating so I must use my i3 to get me in the ballpark.Any insight greatly appreciated.

 

Thanx,

Ray

[+Cardinal Red]

First off I want to point out that the Geocaching standard is WGS84 (not NAD27 or NAD83).

Even though NAD83 and WGS84 are nearly identical. Certainly close enough.

 

GPS coordinates and time are quite similar. Certainly you are aware that there are 60 Seconds in a Minute of time. It isn't much of a strech to understand there are also 60 Seconds in a Minute of GPS coordinates.

45 Seconds = .75 Minutes (45 divided by 60)

The Groundspeak standard doesn't use seconds so this might not be an issue for you right now.

 

There are 60 Minutes in an Hour. There are also 60 Minutes in a Degree. Same math.

15 Minutes = .25 Hours or Degrees (15 divided by 60)

 

So 40 Degrees 30 Minutes = 40.50000 Degrees (30 divided by 60)

 

So whatever coordinate converter you use, do a quick check of the Minutes divided by 60 and add that to the Degrees.

[+QSparrow]

Deleted - my explanation was not clear.

Edited March 4, 2007 by QSparrow

[raybonz]

First off I want to point out that the Geocaching standard is WGS84 (not NAD27 or NAD83).

Even though NAD83 and WGS84 are nearly identical. Certainly close enough.

 

GPS coordinates and time are quite similar. Certainly you are aware that there are 60 Seconds in a Minute of time. It isn't much of a strech to understand there are also 60 Seconds in a Minute of GPS coordinates.

45 Seconds = .75 Minutes (45 divided by 60)

The Groundspeak standard doesn't use seconds so this might not be an issue for you right now.

 

There are 60 Minutes in an Hour. There are also 60 Minutes in a Degree. Same math.

15 Minutes = .25 Hours or Degrees (15 divided by 60)

 

So 40 Degrees 30 Minutes = 40.50000 Degrees (30 divided by 60)

 

So whatever coordinate converter you use, do a quick check of the Minutes divided by 60 and add that to the Degrees.

Thanx for the reply. You would think that the JEEEP translater would not put you 12 miles off course. I will try what you said and see if the numbers jive. I know the geocaching standard is wgs84 and jeeep lumps that with nad83 . From what I read at Garmins's site my i3 uses nad27 and even then it should only be off by 200m from wgs84. Something just doesn't make sense that JEEEP would be that far off that's what bugs me about this. One thing I would also like to know is if I were to buy a VentureCx and also use that for navigation can wgs84 formatted #'s be input for driving coordinates? That sure would simplify things and reduce errors like this.

 

Ray

[+Urubu]

This is driving me crazy. When I find a cache I want to visit I convert the coordinates to decimal so I can load them into my Garmin Streetpilot i3. I am using JEEEP.com translation and for some reason the coords it gives me puts me way off course. [...]

Ray

 

Ray, can you give the numbers -- the original DMS and the converted decimal? Seeing an example might help a lot in figuring out the problem.

[+Prime Suspect]

This is driving me crazy. When I find a cache I want to visit I convert the coordinates to decimal so I can load them into my Garmin Streetpilot i3. I am using JEEEP.com translation and for some reason the coords it gives me puts me way off course. Today I tried doing this and my i3 had me 12 miles off course when I arrived at destination!! This doesn't make any sense to me. I tried both map datums(NAD27&83) and same results both times. The GPS is fine and I am copying and pasting plus dbl. checking and all data is entered correctly into the poi file I'm creating yet it throws me WAY off. Does someone have a better way to translate deg.\min.\sec. to decimal ? I have absolutely no problem getting decimal coords from addresses ONLY the conversion problem. My handheld is no good for navigating so I must use my i3 to get me in the ballpark.Any insight greatly appreciated.

 

Thanx,

Ray

I think your problem is that you're trying to convert from degree/min/sec, and the coordinates in geocaching aren't in that format. They're in degree/decimal minutes.

[+fizzymagic]

if you are using Windows, you could try my little GeoCalc program. You can copy and paste the coordinates from the cache page directly into it and it will convert them to a variety of formats. No need to guess what format they are in.

[raybonz]

This is driving me crazy. When I find a cache I want to visit I convert the coordinates to decimal so I can load them into my Garmin Streetpilot i3. I am using JEEEP.com translation and for some reason the coords it gives me puts me way off course. Today I tried doing this and my i3 had me 12 miles off course when I arrived at destination!! This doesn't make any sense to me. I tried both map datums(NAD27&83) and same results both times. The GPS is fine and I am copying and pasting plus dbl. checking and all data is entered correctly into the poi file I'm creating yet it throws me WAY off. Does someone have a better way to translate deg.\min.\sec. to decimal ? I have absolutely no problem getting decimal coords from addresses ONLY the conversion problem. My handheld is no good for navigating so I must use my i3 to get me in the ballpark.Any insight greatly appreciated.

 

Thanx,

Ray

I think your problem is that you're trying to convert from degree/min/sec, and the coordinates in geocaching aren't in that format. They're in degree/decimal minutes.

Wow I think you hit the nail on the head with that one! Feeling pretty stupid right about now. Thanx for pointing that out..

 

Ray

[raybonz]

if you are using Windows, you could try my little GeoCalc program. You can copy and paste the coordinates from the cache page directly into it and it will convert them to a variety of formats. No need to guess what format they are in.

Hi Fizzy thank you for the software! That should be just the thing I need.

 

Ray

[raybonz]

This is driving me crazy. When I find a cache I want to visit I convert the coordinates to decimal so I can load them into my Garmin Streetpilot i3. I am using JEEEP.com translation and for some reason the coords it gives me puts me way off course. [...]

Ray

 

Ray, can you give the numbers -- the original DMS and the converted decimal? Seeing an example might help a lot in figuring out the problem.

Thanx for the offer I am going to try a few things on my own before I take this any further. If I am still having trouble I will do as you asked.

 

Ray

[raybonz]

if you are using Windows, you could try my little GeoCalc program. You can copy and paste the coordinates from the cache page directly into it and it will convert them to a variety of formats. No need to guess what format they are in.

Fizzy that's just the program I needed! Impressive job, did you code this yourself?

 

Thanx,

Ray

[Difficult Run]

I've used Fizzy's GeoCalc program for about a year now.

 

... Nicely done Fizzy!