Geocaching Australia

Also, you can ignore the bit about WGS84 datum. What it means is, over the years there have been a few different standards (called datums) for specifying coordinates, and the same coordinate in different datums can be hundreds of metres from each other. But nowadays everything (including smartphone...

Anybody serious about safety then PLB is really the first choice. Things like SPOT etc have a place but should be a secondary consideration.

Also over the life of the device the PLB will be overall the cheapest (and best) option anyway.

maccamob wrote:In $Australian: http://alwaysinreach.com.au/index.php/p ... e/15-rates

Some could get a bill shock from those subscription rates! Quite expensive in fact and not really anywhere near a comparative rate when compared to SPOT?

Not that the following is really applicable in this situation (yet) but something to think about when considering accuracy. Reason why it is not applicable is the typical SPS type receivers used here can not determine accuracy comparisons (limited both by accuracy and precision) less than around 2.6...

Rainbow Spirit wrote:Where's geomatica when you need him? He is/was a surveyor, and would know the answer to this question..

Is there more to the answers above?

There is no standard GPS that can indicate accuracy as accuracy is relative to a known position of truth and typically no receiver knows where it actually is. What many SPS receivers indicate is Estimated Position Error (EPE) but this is a computed value and can be rather biased, is not computed the...

That appears more likely a cadastral reference mark as even opposed to a permanent survey mark? Typically cadastral boundaries are referenced to buried marks (pins), trees etc but in the concrete and asphalt jungle the only reference options are typically things like bolts/ramsets/Gin's etc in kerbs...

There's really no such thing as an ECW that has been scanned at to high a resolution, all the higher resolution does is increase the file size dependent on the coverage area. ECW's with 10cm pixels make thins look real good, just got to have the system to handle the file size.

GPS results? nah would have come from some inexperienced CAD user, calculator syndrome, all those decimals have to be more accurate (looking). Would be interesting to know with all that precision (not accuracy) did they bother to include the datum? Anyway there is only 2 places in oz that site could...

In simple terms there is no GPS that can report "accuracy" as accuracy is based on knowing the real world coordinates and no GPS has this info. The "accuracy" or EPE most receivers display are nothing more than an assumption and very heavily tied to propriety algorithms which typically display so ca...

I believe one can forget about Lightsquared getting the go ahead based on the current submission proposal.

There is absolutely no way that anything will be allowed to affect GPS.

I don't think they know much about Hendra at all and I don't believe we are being told the complete story? Flying foxes have been around for yonks, so have horses yet it's only been in recent years that this hendra thing has showed up in horses and btw has anybody noticed not just any old horse :rol...

The levelling runs provide basically just height differences between subsequent marks. On a very small scale take four marks being the corners of a square, we could level between each corner along the sides of the square as well as accross the diagonals to give six (6) height differences between fou...

How do you find out what the height datum is for a particular location? Depends on the accuracy you require? All topographical maps are typically AHD (contours/spot heights), physically level from an AHD Bench mark, by GPS means and AusGeoid09. And also be aware that (the biggest majority of) flood...

This levelling didn't all occur over one day but was built up over quite some time. Two-way levelling is basically starting from bench mark 1 levelling to the bench mark 2 then levelling back to bench mark 1, compare the difference and if out of tolerance then do it all again. Much of this levelling...