Klemmer
-
Posts
1553 -
Joined
-
Last visited
Posts posted by Klemmer
-
-
Hi Four Hoofs:
Welcome to Benchmark Hunting!
The Permanent Identification (PID) numbers for Survey Markers are in the format of two letters and four numbers (like DX3291). They are the common cross reference numbers used by the National Geodetic Survey (NGS) and many other agencies (and even us amateur benchmark hunters!).
As you probably realize, the "DX" number IS a PID. There are all the other two letter pairs used, and they are more or less geographically distributed around the US (and possessions). Because you asked about "DX" numbers, I can tell you are probably in Southern California (because I am also).
Where to find the PIDs? Well, they are on the top of every benchmark page in the geocaching benchmark section. Wher eto find the benchmarks? Well, that's the real question, right?
Over in the benchmark hunting forum, there is a very helpful topic at the top titled "Me First!". If you haven't browsed it, you might consider doing that. Feel free to ask any other questions you might have over there, which is a bit more informal than this section, which is intended for more pointed technical issues involving the NGS (but no problem starting here, we're not that formal!).
Also, there is a lot of good info on the Benchmark Hunting page, if you haven't seen that info (scroll down a bit).
Good Luck! Let me know if I can help you out, since we might be "neighbors". You can send me an email through our geocaching profle, or a PM through these forums.
Klemmer
-
Worked for me too, after I turned on ALL options. Now I need to turn most off again....
So.... can I log it on GC.com?
-
eBay, about $7 + a couple bucks shipping.
-
Bill:
Hah! 1947 model would have been a tough one person carry! Yeah. And I know what a 6SN7 is. I also still have a tube tester that will test almost any tube (Military Surplus TV-7). End of thread hijack.
-
I love it when individual human beings are referred to as "the computer " or "the assistant computer". It really bring us back to our roots........
I suspect it would go right over the head on many (but not all!) of the younger generation (under, say, 18 or so).
-
Here's one from my recent trip to Australia. Unfortunately, there is no public (free) database for Survey Marks in Australia that I could find. But I have no doubt that this IS a horizontal control mark, likely a pretty old one. The bridge is the famous Sydney Harbor Bridge, which I was able to climb, as part of an organized group climb to the top. Loads of fun, a must-do if you get there. Not as strenuous as I had thought it would be. The famous Sydney Opera House is just around the corner, but I couldn't get it in the picture with this or any other BM I could find. Fun trip (mostly business).
-
That monument is downright... chatty? Lots of neat information, for sure. Cool find.
-
I can contribute a bit on the gravity stations:
They are very important to our Department of Defense and NASA, since knowing the exact gravity gradients in various areas of the earth are critical to proper space (orbital or ballistic) navigation, and other "scientific reasons". Large efforts were undertaken starting at the beginning of the "space age". Of course there were gravity measurements previously, but these measurements, coupled with critical location (i.e. accurate geodetic position) had just become more important. I have seen gravity stations more commonly near DOD or NASA installation. BDT: Any near such facilities near your gravity station grouping?
Above is a very short summary (by me, no research) of a very complex subject.
(BTW: Happy Veteran's Day to the other Vets out there!)
EDIT: DaveD beat me to the punch on gravity, and with more survey related details (thanks!), but I'll stand by the above as well.
-
Definitely not a crazy idea. I still use my old Maggy Meridian for certain tasks (e.g. multiple 500 waypoint files), and would love to have it capapble of using WAAS corrections once again.
I would support such an effort. I'm not capable myself, unfortunately. I know a couple hot-shot young software techie types that might help. Is uClinux the operating system that the Meridians used? Or is it just one that will run on that hardware (so I can ask the right questions of my software types)?
Obviously, I would be OK with beta testing. I have other primary GPSr's I could use (Garmin, Delorme). If my maggy got permanently "bricked", I wouldn't cry for too long.
-
Enjoyable read. Traveling on business in Australia (Brisbane). Nice to read about something from back home. Thanks!
-
Ahhh... Good old Picacho Peak... It was a great landmark for navigating around that area when I was in USAF pilot training. Used to fly T-41's (a striped down Cessna 172) out of a little strip somewhere across the Interstate from Maranna Airpark (which I see is now Evergreen Air Center). Can't remember the name, and don't see it on Google earth anymore. Also later flying T-37's and T-38's, we used to use an old strip somewhere around Coolidge (Williams Aux Field 2? Called it Headpin) for "touch & go's". But I sure do remember Picacho Peak! Thanks for the memories!
Edit: OK, I had to go find my old USAF log book. It was Eloy Municipal Airport, which still appears to be there, and seems to be an active Skydiving center. Cool. Further North than I remembered.
Edit2: OK, The old Headpin field is now Coolidge Municipal Airport
Thanks again!
-
Cool! Thanks. Definitely related. Survey problem? Sounds like it was. Data error.
-
-
johnling:
Thanks to ex-president Clinton, there have not been any intentional errors inserted into the GPS signal since around May 2000, previously known as Selective Availability (SA).
-
I've always maintained that the marketing department of a GPSr manufacturer has a major input into the formula for EPE. They certainly don't want to see a large number!
-
There is a new article in "Inside GNSS" about improvements of the NGS CORS sites:
"NOAA Expands CORS Reference Sites"
Also info in there about the recently added WAAS sites.
Sometimes the printed magazine articles are a little longer than on their website. I get the print version (but not yet here). If there is more, I'll share it, if I can do so without stepping on copyright issues.
The magazine can be very interesting for the more technically inclined who are interested in the nuts & bolts of GPS and it's worldwide cousins. There are typically several more articles in the print version that are not on-line. I think they put them up as pdf's in the archives when the new print issue comes out, so check "past issues" on the website periodically (pardon the intentional pun).
-
If you want to read about the leading edge (bleeding edge?) technology of GPS, Inside GNSS is really good. I happened to remember an article about inertial sensors being used with GPS receivers: Integrating Inertial Sensors with GNSS Receivers. Enjoy.
-
Agree. Stay away from Magellan.
-
When it first came out, I wrote about it's mapping capability, and in particular the XM radio hook-up, with NEXRAD Radar images downloadable real-time. Pretty cool. Looked at one at REI, but didn't buy. Now that Sirius bought XM (or they merged, whatever), I wonder where that is going now.
-
However, with Delorme's XMap software package, you can load up several GIS map file formats, or even scan paper maps, and load them into their PN-20 or their new (available soon) PN-40.
I suspect the Canadian Government might have some compatible topo map files tucked away somewhere, if you can get hold of them.
P.S. If you have one of their GPS receivers, be sure to let them know. They usually discount XMap by 50% or so for owners.
-
My take:
--> Garmin is primarily an electronics company (professional level GPS receivers, airborne, etc) that also sells electronic maps.
--> Delorme is a primarily mapping company (professional level GIS mapping software, etc) that also sells GPS receivers.
I think those statements are factual, and reasonably fair to both companies. Someone may nitpick them, but you get the idea.
So - take your pick - which is more important to you?
On a personal note, mapping is much more important to me. I was using Delorme mapping software (Topo USA ver 3.0 & TopoQuads ver 1.0) for years before they sold their first handheld unit (the PN-20). [Note: Yes, I know Delorme sold "receiver only" type units before that, but it's not practical to carry a laptop in the woods!]. I have also owned (still own!) several Garmin units and a Magellan. All had their day. I now use my Delorme PN-20 95% of the time, and have a PN-40 on order. Draw your own conclusions.
P.S. I know a fair amount about mapping on GPS receivers, and have written an article on the subject.
-
To Answer your Question:
STAY AWAY FROM MAGELLAN. Zero customer support (unless you speak Hindi or whatever).
-
Interesting. Thanks, Dave.
{I also had to look up what a Frustum was. You'd think as an engineer I'd have known. Nope.}
-
One general tip, applicable to most units, certainly the three I own:
Be sure you have a good solid GPS signal lock (multiple good sats), BEFORE you reset or turn on your odometer or track log. During the initial stages of a unit locking up, it can at first think you are .2 mi or more away from where you really are. As the lock-up process continues, the position improves. This can easily skew your results, usually to the high side. On both an older Garmin & Magellan, as well as my current Delorme PN-20, this can happen easily.
In summary: get a good lock first, THEN turn on or reset odometer / track.
Of course, as explained well above, there are other issues. But in my experience, good lock before resets minimizes the problems. I only see a few %, maybe 10% max, differences.
Is it worth upgrading from a Colorado 300 to a Delorme PN-40
in GPS technology and devices
Posted
Like Embra, I'm a happy PN-40 owner, and I won't pretend to be unbiased. I have also owned / still own various Garmin & Magellan units, so I'm not unfamiliar with them. I was very close to buying a 60CSx when I bought the PN-20. I'm glad I did, and even more so with the PN-40.
My use is off-road (built-in Nav system in my jeep for road routing).
Data layering: Multi-layer vectors (like Topo USA that come withthe PN-40) is one thing, but the REAL cool multi-layer, which I think only a Delorme PN-20 / 40 can do is to automatically, as you zoom in, you can transition from Topo USA (vector) at higher levels, to USGS 7.5 minute Topos (raster) at mid level zoom, to color aerial photos (USGS CDOQQ - raster) at lowest levels. THAT is data layering! We have a term for it in my business "siuational awarness". Can't be beat. It is not difficult to setup, just takes a little getting used to "cutting" the right zoom levels in Topo USA, and setting up the layering inthe PN-40. Once setup, it's seamless, and fast. Love it for caching, benchmark hunting, hiking, mountain biking.