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Why not use the hddd.mm.ss.s format?

#1 User is offline   TeeGate 

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Posted 23 June 2002 - 11:03 AM

Since I have been photographing and reporting Benchmarks I decided to check out your site, and I noticed that I have not been able to find anyone who uses the hddd.mm.ss.s format. The USGS uses that format, and that is the reason many of the searchers on this site have problems getting the reading on the PID to match with their GPS unit.

Or are you converting them over by using 1.666, or does this site do that for you?

It seems to me that if the original datasheet coordinates have been GPS observed, you would be more incline to accurately locate your benchmark using the hddd.mm.ss.sxxxx format. Using the format that I see on this site has always kept me from accurately finding a benchmark.

Guy

#2 User is offline   iryshe 

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Posted 23 June 2002 - 03:20 PM

I'm not sure what your question is. Who is "you" in this post? Are you discussing accuracy of the geocaching.com site using benchmarks?

Jeremy Irish
Groundspeak - The Language of Location

#3 User is offline   unclerojelio 

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Posted 23 June 2002 - 11:16 PM

[QUOTE Originally posted by TeeGate:

It seems to me that if the original datasheet coordinates have been GPS observed, you would be more incline to accurately locate your benchmark using the hddd.mm.ss.sxxxx format. Using the format that I see on this site has always kept me from accurately finding a benchmark.
Guy[/QUOTE]

Why?
hddd mm.mmm and hddd mm ss.s both are more precise than your GPS is accurate. Posted Image

... Two roads diverged in a wood, and I--
I took the one less traveled by, ...

unclerojelio

#4 User is offline   unclerojelio 

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Posted 23 June 2002 - 11:16 PM

[QUOTE Originally posted by TeeGate:

It seems to me that if the original datasheet coordinates have been GPS observed, you would be more incline to accurately locate your benchmark using the hddd.mm.ss.sxxxx format. Using the format that I see on this site has always kept me from accurately finding a benchmark.
Guy[/QUOTE]

Why?
hddd mm.mmm and hddd mm ss.s both are more precise than your GPS is accurate. /infopop/emoticons/icon_rolleyes.gif

... Two roads diverged in a wood, and I--
I took the one less traveled by, ...

unclerojelio

#5 User is offline   TeeGate 

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Posted 24 June 2002 - 06:50 AM

Jeremy,

I am not discussing the accuracy of geocaching.com at all. It is accurate and a great site. I just am wondering why this site uses the hddd mm.mmm format for Benchmark searching, when the USGS uses hddd mm ss.s. The reason why I ask that is because from reading on the web and a few instances on your site, many users of GPS units do not understand why when they compare their readings to the PID they do not match at all.

I am convinced that many users think that if the PID says for example 00.00.50 they should go to 00.00.500, and that would not be correct. They should be going to 00.00.833. Most people think that by adding a 0 on the end does not change the number, but with the two formats it does.

Hopefully my post did not make it look like I was criticizing this site. I enjoy reading and viewing the posts, and plan on posting in the future.

Guy

#6 User is offline   mph6563 

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Posted 04 July 2002 - 12:16 AM

quote:
Originally posted by TeeGate:
I just am wondering why this site uses the hddd mm.mmm format for Benchmark searching, when the USGS uses hddd mm ss.s.


Probably because GPS receivers tend to come out of the box set for hddd mm.mmm. My eTrex did. Now, why the GPSr manufacturers prefer that format, I can't say.

#7 User is offline   SecretSpy 

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Posted 26 July 2002 - 05:32 AM

I thought the GPSr does all the converting for us.


LowlyWorm Says Gig 'em Aggies

#8 User is offline   unclerojelio 

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Posted 26 July 2002 - 05:48 AM

quote:
Originally posted by SecretSpy & LowlyWorm:
I thought the GPSr does all the converting for us.

http://img.groundspeak.com/cache/5399_600.jpg
_LowlyWorm Says Gig 'em Aggies_



Silly aggie - I think the problem TeeGate is trying to get at is that some folks ( aggies mainly Posted Image) don't know the difference between the two formats. Yes, your gps will do the conversion, but you gotta know that the conversion is needed in the first place.

... Two roads diverged in a wood, and I--
I took the one less traveled by, ...

unclerojelio

#9 User is offline   unclerojelio 

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Posted 26 July 2002 - 05:48 AM

quote:
Originally posted by SecretSpy & LowlyWorm:
I thought the GPSr does all the converting for us.

http://img.groundspeak.com/cache/5399_600.jpg
_LowlyWorm Says Gig 'em Aggies_



Silly aggie - I think the problem TeeGate is trying to get at is that some folks ( aggies mainly /infopop/emoticons/icon_rolleyes.gif) don't know the difference between the two formats. Yes, your gps will do the conversion, but you gotta know that the conversion is needed in the first place.

... Two roads diverged in a wood, and I--
I took the one less traveled by, ...

unclerojelio

#10 User is offline   Web-ling 

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Posted 26 July 2002 - 08:09 AM

I suspect the reason Jeremy set up the Benchmark pages to use hdddºmm.mmm rather than the hdddºmm'ss.s" format is because that's the way geocaches were set up. The vast majority of benchmark hunters were geocachers first, and it's a pain to have to keep switching the settings on a GPS to go back and forth between formats. If I remember another thread correctly, the reason geocaches were set up with the hdddºmm.mmm format is because that's how most GPSs have their defaults set when they come out of the box.



#11 User is offline   TeeGate 

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Posted 26 July 2002 - 11:49 AM

If someone is just posting to the Geocaching website, there is no question staying with the hdddºmm.mmm format is probably the correct way to go. But it is clear that many members are submitting their finds to the NGS which can cause a problem if they leave comments. Many times if I find a coordinate on a PID that appears to be inaccurate I leave the coordinates that I get from my GPS in the comment field.


JU0601 STATION RECOVERY (2002)
JU0601
JU0601'RECOVERY NOTE BY INDIVIDUAL CONTRIBUTORS 2002 (GJT)
JU0601'PORTABLE GPS READING
JU0601'N39.44.10.2
JU0601'W074.43.37.9

They seem to be quite accommodating and put whatever reading you give them in the comment section. So if someone who does not know about the format difference submits their readings, can you imagine the confusion that it "may" cause. Not counting the confusion by the NGS staff deciding if the coordinates submitted to them are accurate.

The information submitted to the NGS needs to be as accurate as possible, so it just seems to me that it is in the best interest of the members of this site to understand the difference. Who knows...if they find the information they are getting is flawed, they may restrict access to this information in the future.

BTW in previous posts I incorrectly mentioned USGS instead of NGS. We all make mistakes, some more important then others. Sorry for the error.

Guy

#12 User is offline   survey tech 

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Posted 27 July 2002 - 04:55 AM

GJT
The comments in your example are fine. You are right that it can be helpful to others to note that your coordinates are handheld, so this is a good idea. There is no need to be too concerned about any confusion over coordinates, since coordinates on benchmarks are understood to be only approximate, and are never used for any precise purposes, because benchmarks serve to provide elevations rather than locations. Only horizontal control points must have precise coordinates, and no handheld coordinates can reach the level of precision required for these points. The value of the information to NGS is not in the accuracy of the coordinates, but in the fact that it provides an indication of whether or not the marker still exists. Professionals may read your comments and decide from them whether or not it is worth taking time to look for a particular marker, so the most important thing is to correctly state whether or not the marker remains in place. You could also help by updating the description of how to reach the marker with any new roads, buildings, etc., but your coordinates will not be used by professionals, regardless of format. The NGS is required to provide their information to the public, since it is a taxpayer funded organization and the info is specifically gathered, processed and stored for public use, not for security or defense purposes, so no need to worry about being shutout. Its entirely up to the public to use the info judiciously.

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