[talk-au] Tasmanian Survey Marks

[Brett Russell]

Hi 
 
When searching for survey marks I came across this link that lists the known survey marks, http://www.dpiw.tas.gov.au/inter.nsf/Attachments/NBON-75X7RM?open in a CSV format for Tasmanian.  Not suggesting that this is imported into OSM as not aware of the copyright issues but at long last I have come across something that will enable me to check my Garmin 62s' accuracy and give the ability to align Bing when I find them on the ground providing that they can be seen from Bing.  Be great if they are in nice circles of paving but something tells me I will not be that lucky but a bit of averaging should get a couple of metres of accuracy.   This will means I can fix up some roads (split lanes) alignment so I am not told to turn-around and go back as happened to me in Launceston.   Also avoid GPS wars where mine is better than yours as I have noticed when playing with GPS that one brand is consistently 10 or so metres out.  Also spotted something similar when checking my traces to other traces loaded into OSM.  
 
Been reading up on GPS accuracy and playing with averaging waypoints on the Garmin 62S and have realised that WAAS does not work outside the USA and for some units better to have it switched off.  If I wrong in my understanding please let me know.  I can be rather a precision freak but be nice to get thing right.  Still interested in the most accurate GPS outside professional units but given the WAAS issue tend to think USA based comparisons are flawed.  Did find an interesting article from the Berkeley University GIS section where high end standard consumer GPS actually perform better than some of the professional units where base station correction is not available or reception is compromised by locational issues such as tree cover.
 
Now it would be great to permanently align Bing in Polatch 2 but this does not appear possible and I need to read up in JOSM to find the means to do this.  Generally finding Bing around 10 metres or better correct in native format (assuming my GSP is that good) but some tiles the overlap can be out by more than that which is especially noticeable on things like lakes that cover more than one photographic tile
 
Cheers Brett
 		 	   		  
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