How Many Gcxxxx Combinations?

[+Army1]

With so many waypoints being tracked as GCxxxx, how many combinations can there be? I assume the GC stays the same, but then there are 36 possible alpha-numeric values (26 letters plus ten numbers) for each of four positions. I guess the same could be asked of the $340M PowerBall tonight...OMG!--I need to go buy some...thanks,...bye :-)

[+The Leprechauns]

Not quite. Certain letters are skipped so that a waypoint can't spell out a "bad" word, while other letters like "I" and "L" and "O" are skipped so as not to be confused with numerals that are similar in appearance. And the current numbering scheme has not always been in effect.

Edited October 19, 2005 by The Leprechauns

[+TheFreshwaterAnglers]

I believe that would be 1,679,616 possible combinations available. That is, if my math is correct.

 

T.

[+Markwell]

I know it's Base 31.

 

I'm not sure exactly what 5 characters are missing, but I know they've eliminated i, o and some others due to confusion in readouts... Someone else will chime in with the definitive answer.

[+OienLabs]

I believe that would be 1,679,616 possible combinations available.  That is, if my math is correct.

 

T.

And how long will the 4 character combination last? Until next year and then 5 characters is needed (plus the leading GC)? The speed of this evolution impresses me.

[+TheFreshwaterAnglers]

I know it's Base 31.

 

I'm not sure exactly what 5 characters are missing, but I know they've eliminated i, o and some others due to confusion in readouts... Someone else will chime in with the definitive answer.

If it's base 31, then there should be approximately 923521 combinations. Again, that is if my math is correct.

 

T.

[+The Leprechauns]

I know it's Base 31.

 

I'm not sure exactly what 5 characters are missing, but I know they've eliminated i, o and some others due to confusion in readouts...  Someone else will chime in with the definitive answer.

If it's base 31, then there should be approximately 923521 combinations. Again, that is if my math is correct.

 

T.

I don't think so. I believe that this is the definitive explanation from the time when the conversion over from simple Hex was being discussed.

[+fizzymagic]

The last 4-letter combination, GCZZZZ, will be cache # 512,400. It's complicated because caches below GCG000 were encoded as hex numbers, so many possible combinations were not included.

 

When the Great Cache Number Exhaustion arrives (I am predicting the spring of 2007), TPTB have indicated that the waypoint names will simply get one character longer. That gives a lot of headroom; GCZZZZZ is cache # 28,218,030.

[+Army1]

The last 4-letter combination, GCZZZZ, will be cache # 512,400.  It's complicated because caches below GCG000 were encoded as hex numbers, so many possible combinations were not included.

 

When the Great Cache Number Exhaustion arrives (I am predicting the spring of 2007), TPTB have indicated that the waypoint names will simply get one character longer.  That gives a lot of headroom; GCZZZZZ is cache # 28,218,030.

Great, do you think the Garmin folks will update their software to allow seven-digit waypoint names, up from the current six-digit limitation?

[+The Leprechauns]

You could either use that as an excuse to replace an old GPS receiver, or you could use GPX Spinner or GPS Babel to re-name the waypoints in a batch procedure that will skinny them down to six digits. I already strip "GC" out of my waypoint names before loading them onto my GPS.

[+Team Perks]

Great, do you think the Garmin folks will update their software to allow seven-digit waypoint names, up from the current six-digit limitation?

Are ya kidding? I'm using it as an excuse to get a new GPS!

 

(Okay, so my current GPS will read more than 7 digits...and I send waypoints through GSAK to strip out the "GC" anyway...but any excuse is a good excuse! )

 

Edit: Leprechauns type faster than kittens...beat me to the punch.

Edited October 19, 2005 by Team Perks

[+Thrak]

I already strip "GC" out of my waypoint names before loading them onto my GPS.

How would one go about that?

[+The Leprechauns]

I already strip "GC" out of my waypoint names before loading them onto my GPS.

How would one go about that?

By setting that up in your user preferences for GPX Spinner (in the .ini file). GSAK has a similar functionality but I don't use that. For details, the GPX Units and Software Forum is the best place to ask.

[+The Jester]

I already strip "GC" out of my waypoint names before loading them onto my GPS.

How would one go about that?

In GSAK on the 'Send Waypoints to GPS' dialog, in the waypoint name field use %drop2 instead of %code. Look up "special tags" in the help file for more options.

[+cachew nut]

I suggested dropping the "GC" in the old thread but was told it wouldn't happen. Now I sit quietly waiting for the day that the system finally runs out of numbers and must drop the GC. At first I was bummed because I thought I probably won't even be geocaching when that day comes along, but at the rate new numbers are being used, I will see that day. In the mean time I sit quietly waiting...

[WH]

I believe that the GC is used to denote geocache, TB for travel bug, JP for jeep etc etc.

[markandlynn]

The GC at the front is grounspeaks prefix as designated by gpx standards navicache, terracache etc all have thier own two letter prefix. Hence the GC prefix from this site cant be dropped.

Edited October 20, 2005 by markandlynn

[+Jhwk]

dang...

 

drop the IOL

 

carry the 2

 

add...

 

Seven!

[+V-I-cacher]

Are "old" numbers being "recycled" properly?

If a cache is archived, it's waypoint should be stripped for use on another cache.

[+geognerd]

Are "old" numbers being "recycled" properly?

If a cache is archived, it's waypoint should be stripped for use on another cache.

Yeah, but what if you wanted to look back at an old log entry or photographs? How would you be able to look up the archived cache without an ID? You could assign the archived caches new non-GC IDs and recycle their original IDs but that's too much trouble.

 

And as Fizzymagic said:

That gives a lot of headroom; GCZZZZZ is cache # 28,218,030.

 

With the 7-character ID, we will have plenty of IDs to use.

[+KKTH3]

What if GC-GZ were all designated as Geocaching? Then we go on to GD0000 after GCZZZZ and carry on that way.

[+Airmapper]

Are "old" numbers being "recycled" properly?

If a cache is archived, it's waypoint should be stripped for use on another cache.

Yeah, but what if you wanted to look back at an old log entry or photographs? How would you be able to look up the archived cache without an ID? You could assign the archived caches new non-GC IDs and recycle their original IDs but that's too much trouble.

 

And as Fizzymagic said:

That gives a lot of headroom; GCZZZZZ is cache # 28,218,030.

 

With the 7-character ID, we will have plenty of IDs to use.

coulden't an archived cache be given a new prefix? Only the first two letters would change, Example:

 

GC123A

would become

AR123A

Edited October 20, 2005 by Airmapper

[+fizzymagic]

Are "old" numbers being "recycled" properly?

If a cache is archived, it's waypoint should be stripped for use on another cache.

That would be very, very bad.

 

For a good database design, each waypoint must correspond to exactly one record, archived or not.

 

All this has been hashed out before. See this discussion, and this discussion, for example. Also see this thread for a discussion of the rate caches are being placed.

 

Each waypoint named can be uniquely mapped to a cache number. For example, GCQZ82 is cache number 303153. There are a lot of advantages to having this property in the database.

 

Oh -- by the way, GeoCalc will do the waypoint <-> cache number conversions for you.

Edited October 20, 2005 by fizzymagic

[markandlynn]

What if GC-GZ were all designated as Geocaching? Then we go on to GD0000 after GCZZZZ and carry on that way.

They cant GC = Groundspeak

TC = terracache

NC= navicache

GD = geodashing

etc

etc

[+Jeep_Dog]

This is a nice, intellectual discussion, and good math/hex lesson.

 

However, now that I have gotten smart reading all of this wonderful discussion, I resolve to not worry about it. The only circumstance I could fathom generating a concern is if I submit a cache, and get some sort of error in return that says "Oops, we are all out of cache waypoints. Sorry." In this case, I would get on the website forum and say "hey, you wonderful folks at GC, we ran out of waypoints," and I am sure they will be all over it. I have a feeling a 5th digit would be added prior to that point being reached.

 

Personally, I am more concerned about what happens to our computers as we turn over to the year 3000...

 

edit: I had some smart math-based comment to add to the discussion, but decided to be silly instead.

Edited October 20, 2005 by Jeep_Dog

[+Prime Suspect]

coulden't an archived cache be given a new prefix? Only the first two letters would change, Example:

 

GC123A

would become

AR123A

That's not re-using anything. That's just creating an entirely new waypoint.

[+AtoZ]

They will just add a new character position. Did it in the past will probable do it again. how many characters will you GPSr hold, LOL.

cheers

[robertlipe]

The GC at the front is grounspeaks prefix as designated by gpx standards navicache, terracache etc all have thier own two letter prefix. Hence the GC prefix from this site cant be dropped.

I've seen this a couple of times now and I have to step up. To be clear (and I'm an active member of the GPX standards team, as are reps of Groundspeak) the GPX standard designates no such thing. There may be convention and tradition and so on, but the GPX standard itself is not in the business of doling up waypoint names.

 

Groundspeak can put anything they like in a wpt/name tag that doesn't violate the requirements of http://www.topografix.com/gpx_manual.asp#name

 

They could name all of them iwth prefixes like NC/TC or they could identically name every last waypoint in a pocket query all "Madame Blueberry" Neither of those would be particularly wise and I don't think the staff of the site is using enough drugs to do this (or reuse primary keys in the database as has been suggested here, but that's a different thing...), but the GPX standard itself would be fine with that.

[+The Jester]

coulden't an archived cache be given a new prefix? Only the first two letters would change, Example:

 

GC123A

would become

AR123A

Aside from the other problems with this mentioned above, what happens when the NEW GC123A is archived?

[+V-I-cacher]

coulden't an archived cache be given a new prefix? Only the first two letters would change, Example:

 

GC123A

would become

AR123A

Aside from the other problems with this mentioned above, what happens when the NEW GC123A is archived?

well, that wouldn't be a problem either:

 

A1123A

A2123A

up to

AY123A

AZ123A

 

that's a lot of archivable caches for one GC-code!

[+NomadVW]

Great, do you think the Garmin folks will update their software to allow seven-digit waypoint names, up from the current six-digit limitation?

Cripes... my 2 yr old GPSr does 10 digit waypoint names already. I have some time before mine gets obsolete, I guess.

 

VW

[4wheelin_fool]

My opinion is that microcaches are somewhat different enough to deserve a separate prefix such as MC.

[+Lil Devil]

Hrmph. I thought MC meant Multi-Cache

[+Markwell]

coulden't an archived cache be given a new prefix? Only the first two letters would change, Example:

 

GC123A

would become

AR123A

Aside from the other problems with this mentioned above, what happens when the NEW GC123A is archived?

well, that wouldn't be a problem either:

 

A1123A

A2123A

up to

AY123A

AZ123A

 

that's a lot of archivable caches for one GC-code!

But your ignoring the database people that are indicating that basic designs of database indicate unique waypoints for caches. Many level heading and intelligent people have said that over and over again in this thread and others.

[markandlynn]

There may be convention and tradition and so on, but the GPX standard itself is not in the business of doling up waypoint names.

 

.

Interesting thanks for the clarification robert where would i take a question on this ? nice software by the way

[robertlipe]

There may be convention and tradition  and so on, but the GPX standard itself is not in the business of doling up waypoint names.

Interesting thanks for the clarification robert where would i take a question on this ? nice software by the way

Questions on what GPX spec mandates are best answered by the specs for GPX 1.0 and 1.1 themselves. Questions about intent of the spec are probably best asked on the gpsxml list. Questions about any given implementation of GPX (like Mapsource, GSAK, or Groundspeak, or GPSBabel) are best asked in whatever channel that vendor supports that implementation.

 

And thanx.

[Micqn]

With so many waypoints being tracked as GCxxxx, how many combinations can there be? I assume the GC stays the same, but then there are 36 possible alpha-numeric values (26 letters plus ten numbers) for each of four positions. I guess the same could be asked of the $340M PowerBall tonight...OMG!--I need to go buy some...thanks,...bye :-)

HEY! Thats my cache. Its unavilable right now but thats my cache!

 

GCXXXX - You call this a park?!

[+Prime Suspect]

HEY!  Thats my cache.  Its unavilable right now but thats my cache!

 

GCXXXX - You call this a park?!

I don't think so. They're assigned sequentially, and they're only up to GCR---.