evilC

Well - it would seem that I am a sitter for this one. See this thread on the NZ forums! But of course I'll have to walk 180 metres or so down the road to find S39 WGS84!

Aha! I'm too slow. After finally catching up with the virtual SUPERSONIC TB, I find that it has already been released, and all my "calculations" to locate SandyMount were for zip. So I decided to move the TB to the SandyMount cache anyway, but when I tried to do that I discovered it was "locked". I guess the powers that be don't approve of the concept of a virtual TB bouncing randomly around all the caches in the world. I'm not really surprised - I think I'd have to agree with them - although it is a novel idea....

After sending my email to you pointing out the apparent typo in the position you've given, I realised that the reference position is probably meant to be the opposite side of the world from your home, which would mean something like S 51° 48.688' E 179° 9.685' instead!? Based on that, and calculating distances using Gazza's online geodetic calculator it seems that the SandyMount cache is the closest (although still about 905.5km away!). You can see this cache on the south east part of the penninsula in this map. evilC

Lots of "caching" hints and tips here!

I was recently caught out (slightly) when the location of a newly placed cache was changed a couple of weeks after it first appeared on the site (due, I suspect, to the incorrect datum being used initially by the cache owner). But in the meantime I'd already downloaded the incorrect coordinates to my GPS receiver, and so when I tried to find it I found myself heading for a spot about 200 metres further south than the cache! In other cases, I know some descriptions have been changed or updated in some way, but I've not realised and continued to rely on an earlier printout when trying to find it. One way to avoid the need to have additional automatic notifications would be if caches owners always posted a note if significant changes like this were made. But this doesn't seem to happen consistently, and the automatic notifcation is likely to be a much more robust solution. So what I'd like to receive are additional email notifications for caches on my watchlist telling me when the description was changed in any way. If this was likely to generate too many additional notifications for some people's tastes or needs, then perhaps it could also be an option turned on or off in your profile. The notifications might simply indicate which parts of the cache description had changed rather than showing precise details of what was changed. I.e. Coordinates not changed. Description changed. Hint not changed. What do you think?

PS: The only cache I've hunted near Queenstown is Tobin's Track near Arrowtown, which is a short drive from Queenstown and very popular with visitors from overseas so I guess you'll pass that way at some stage. That cache was great when we visited, was then plundered, but is now (from the logs) up and running in pristine condition again. A nice walk after visiting the cafes in Arrowtown...

I haven't done that much geocaching in Auckland myself, but I would recommend the following: Spring Geometry which is near the Zoo. Domain Terrain which is near the Museum. Both of the above use a similar style and require a bit of time and possibly quite a lot of walking. (Actually - I never managed to finish Spring Geometry but I still enjoyed it!) A much easier cache near central Auckland is Clacker on Mount Eden. Anyway, hope you enjoy your time in NZ! Cheers evilC

Didn't spot this thread until too late, so have a look at my last post to: eTrex automatic datum selection for NZMG display selection

If you want more info about the NZMG and how to convert to and from GD49 look on the LINZ site: http://www.linz.govt.nz/rcs/linz/6137/nzmg.pdf Here are links to a site showing how to use user grid to approximate NZMG and also shows errors you can expect. http://www.ualberta.ca/~norris/gps/nz/NZ.html http://www.ualberta.ca/~norris/gps/nz/NZ4.html There are also various tools and online sites that can convert between NZMG and lat and long with various datums. Good luck!

G'day Brian (aka Bread) quote:Also I know the Garmins have the NZMG built into their software. how accurate and your waypoints usiing the NZMG coordinates? As you say, the Garmins (and hence my etrex) have the NZMG built in. The conversion between that and WGS84 or whatever is pretty much "spot on" as far as I know. So you can convert from WGS84 lat and long to NZMG for use with NZ topo maps if that is what you want to do. The NZMG is a very "specialised" grid though, and as far as I know it isn't possible to get a very accurate approximation using the "user grid" type approach - at least not across the whole country. Not that I have ever really had any need to attempt this myself... Cheers Clive

Hi Aidan For online maps you could have a look at: http://www.wherearewe.co.nz http://www.nztopoonline.linz.govt.nz Cheers Clive

Here are a couple of threads about this topic from late 2001 in case you haven't spotted them: http://opentopic.Groundspeak.com/0/OpenTopic?a=tpc&s=1750973553&f=2860999683&m=8900962783 http://opentopic.Groundspeak.com/0/OpenTopic?a=tpc&s=1750973553&f=2860999683&m=7120962783

For those of you using the yellow etrex, and still using firmware 2.10 or earlier, you may want to make a mental note that when you select the NZMG display format ("New Zealand") the unit automatically updates the datum to GDA instead of Geodetic Datum '49. I only "discovered" this automatic datum change when trying to trying to convert between NZMG coordinates and WGS-84 recently. I didn't see the datum change, and then read out lat and long using GDA (Australian datum) instead of WGS-84 which is what I had selected previously. Anyway, did some research, and eventually decided to upgrade my etrex firmware to 2.14 which is the latest version on Garmin's site even though there was no mention of any changes in this respect. However it is different, and version 2.14 changes the datum to Geodetic Datum '49 instead of GDA when NZMG is selected as the display option. Obviously that was what it was meant to do all along, although I'd rather it didn't change the datum automatically at all. Possibly other similar units have the same problem if using older firmware? Cheers Clive

For the record, here are all the "geographic centres" I came up with, based on processing the 500m resolution DEM data file (NZMG referenced) from www.geographx.co.nz, etc., as described earlier: Geographic Centre of: North Island = E2744374 N6291560 = S38°32.885' E175°41.280' South Island = E2313874 N5691060 = S43°57.728' E170°33.346' All NZ* = E2496874 N5946560 = S41°41.268' E172°50.545' These are NZ Map grid coordinates first, and then WGS-84. The "All NZ" position is generated using all "land" in the DEM data file I used. I don't think this includes far off place like the Chathams, etc., but will include Stewart Island and other smaller coastal islands. The main point of interest to me, is that the "all NZ" location I get is about 60km SW of what appears to be the accepted position near Nelson (see Bullseye Nelson). Including just the two main islands only makes a small difference - the calculated centre moves about 3 km North and 2.5 km East. The North and South Island values come from just those Islands alone. Finally, sharp eyes might spot a small difference in the WGS-84 position for the centre of the South Island when compared with what I gave in an earlier post. I think this typo was caused by my etrex automatically changing the Datum from WGS-84 to GDA (Australia) when I selected "New Zealand" (NZMG) for the display format! I'm sure it didn't do this with the rev 2.09 software when I first got it but now it has rev 2.10 loaded. Anybody else noticed this behaviour? Is there any good reason for that to happen?? GDA is just above Geodetic Datum 49 in the list so perhaps that is what it is supposed to be changing to, but a software bug leaves the index out by one? Maybe... How "accurate" are these "geographic centres"? Hard to say, especially without having even a clear definition of exactly how they should be calculated! But I'd certainly like to be able to compare my results to those generated by other people & methods. The 60 km difference for the total NZ location does puzzle me... for now I am assuming that the powers that be in Nelson were more interested in publicity than accuracy! Cheers Clive [This message was edited by evilC on December 20, 2002 at 07:32 PM.]

I used the DEM data only to determine (roughly) where land was (i.e. elevation above sea level), and where it wasn't. i.e. Didn't use the actual elevation values as such. It seemed pretty clear to me (after searching high and low on the net) that there wasn't really any truly standard definition of "geographic centre". For example, do you include lakes? Surrounding islands? What about effect of curvature of the earth? And variations in density of earth/gravity, etc. But putting all that aside I still like the idea of finding a reasonably accurate "geographic centre", being a purely spatial thing. I also assumed (always a dangerous thing to do but the maths was too hard otherwise!) that the curvature of the earth probably wouldn't be a huge factor for NZ (another advantage to living in a small country ) and that using data based on the NZMG would probably be a good thing also (as it is designed to minimise distortion caused by the projection across NZ). So my gut feeling is that the calcs I did should give a reasonably sensible result - assuming no bugs in my code! Finally, while obsessing about the whole idea of geographic centres, etc., I also considered trying to find the geographic centre of all current NZ caches. Maybe there could be a cache at that point also. Of course this would move over time which give it a pretty high difficulty rating and it would probably need to be virtual also! How about an NZ geocachers conference at that point? This means you'd have a chance to minimise your own travel distance by placing more caches in the appropriate locations...

Here's the link to a page pointing out the location of the geographic centre of NZ: http://www.ts.co.nz/~kevin/web_html/photos/cut.html And here is another which claims to be "near" the centre of the SI?? http://www.huntnzsafaris.com/highpeak.htm

I mis-read the distance from Dog Kennel - mentioned in my previous post above. It is more like 15km north of Dog Kennel - or just less than 10 miles, not kilometres as I said. Previously, I also did quite a bit of searching on the net trying to find out if others had already found or calculated the various geographic centres for NZ. However, all I found for the "mainland" was a very vague description - something like "South Canterbury". I did find a more precise sounding location for the NZ geographic centre although I don't have the URL handy right now. From memory that was on the southern side of hill near Nelson. My quick and dirty C code plus the DEM data didn't agree very well with that though but I never spend much time following up on that one.

After setting up my Centre of the North Island cache I tried to find the centres of both the North and South Islands a bit more "scientifically". I did this by downloading the freely available 500m resolution DEM data for NZ from Geographx and wrote a bit of code to use that data to calculate the approximate geographic centres. My calculated centre for the North Island was only about 2km from the official spot (which was divined back in 1960ish using a large cut-out) so I was pretty pleased to get such close agreement. For the South Island I got a spot just to the east of Lake Tekapo. NZMG coordinates of E2313874 N5691060 which converts to S43°57.826' E170°33.340' according to my etrex. Less than 10km from the Dog Kennel cache. My method ignored offshore islands - all it does it "walk" across all land connected to a given start point (anywhere in the South Island)calculating the average easting and northing. The DEM data I used was referenced to the NZMG. C source code available on request! I also "checked" my results using the "cut out the weather map from the NZ Herald, trim, and balance on a pin" method. Then made a hole at the balance point and visually "overlaid" that over a higher resolution map. This crude check gave suprisingly close agreement. Cheers Clive [This message was edited by evilC on December 18, 2002 at 03:45 PM.]

Some amongst you may wish wish to follow the links below to read about a new source of info from LINZ. http://www.linz.govt.nz/rcs/linz/pub/web/root/core/SurveySystem/GeodeticInfo/positionzfactsheet/index.jsp Or: http://www.linz.govt.nz/rcs/linz/pub/web/root/core/SurveySystem/GeodeticInfo/positionz/index.jsp[/url] Thanks to Vektor for passing this on to me. Cheers Clive

I did check one of the doubled up cache logs but only saw Gatman's more recently dated logs. The earlier one must of been there I guess (it is now!), but I didn't see it. Then when I noticed that earlier reported log entry predated his membership (July 2002) I assumed there was a bug or database problem... Must be going blind.

Not sure if this is a one off case or perhaps a bug introduced with the the recent changes, but in one case when I look at profile of a person and click on "Found", the list includes some finds more than once, incorrectly as far as I can see. e.g. The following seems to show Gatman's most recent three finds twice, once correctly but repeated on an earlier date also (in this case before Gatman was even a member). http://www.geocaching.com/seek/nearest_cache.asp?ul=Gatman

I first read about the Beale papers in Simon Singh's "The Code Book" which I highly recommend if you are are interested in codes and ciphers and their history. Here is one site that questions whether the whole thing is a hoax: http://www.myoutbox.net/bealhome.htm Personally, I find the arguments that it was a hoax pretty convincing now, but it is still a facinating story! I've also since gathered that Buford's Tavern doesn't actually exist any longer (??), and that Montvale used to be called Bufordsville until 1890 or thereabouts. Re the suggestions that seismologists should be able to find it (if it exists), how would they do that? I don't know that much about metal detectors and so forth but it would seem to unlikely that they could detect something buried as deep as this treasure was meant to be? Maybe other better/different technology is available also but how accessible is the whole area anyway. Seems also like there would be quite a wide area to search even if you assume the "about four miles from Buford's" is reasonably accurate. Anyway, my current plan is to spend about $100 on a metal detector (plus a bit more on airfares!), set a waypoint in the middle on Montvale, and then walk in a giant circle (using my etrex of course) of 4.000 miles radius until I hear the tone.... :-)

I've been trying to locate the whereabouts of Buford's Tavern, which is apparently in the vicinty of what is now Montvale VA. My interest in this stems from reading about the Beale Cyphers. See http://www.albany.net/~cybernet/beale.htm for more info if you aren't familiar with the story. I though perhaps someone in the area could even have created a cache linked to this story but apparently not. As far as I can tell the GeoJoker5 cache is about the closest? Anyway, I'd be grateful if anybody can tell me anything more about the precise location of Buford's Tavern, etc. I'm from New Zealand so not likely to be search for the treasure anytime soon but if I crack the cypher I'll be heading your way in a flash!

One thing I find myself doing frequently is browsing through the list of caches in my area (New Zealand) to find and read recent log entries, basically because I'm just curious as to what everybody else is getting up to. I know I could add everything to my watch list but that seems like overkill. Also it doesn't allow an easy way to look at other areas/countries if I wanted to do that. Question... is there already a quick way to do this that I've missed? If not, then how much support is there for a new option allowing sorting of cache lists by date of most recent log entry? I guess other similar options such as sorting total number of logs might be interesting also - a rough and ready measure of "popularity"... Oops! Just found older thread on similar topic = "sort by number of visits" (http://opentopic.Groundspeak.com/0/OpenTopic?a=tpc&s=1750973553&f=6770936793&m=2370925154) but I'll leave this here as some new elements added. [This message was edited by evilC on May 18, 2002 at 04:30 AM.]

I grabbed the LINZ database soon after I purchased my eTrex last year. A severe shortage of geocachers in my neck of the woods meant I was desperate for anything to search for! Although I haven't really checked out many except a handful quite near to home, many of those seemed to be just sitting beside the main road. Not sure if having all of those on www.geocaching.com would be really good or not. However I did spend several hours bush crashing through parts of what used to be State Forest 42 trying to find a more challenging case! No luck even after several separate attempts. Heavy tree cover and my yellow eTrex just don't seem to agree... I guess it won't do any harm so long as it can be integrated into the site in a way that doesn't clutter everything else up too much? [This message was edited by evilC on May 17, 2002 at 04:56 AM.]