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Post by Brent George on Jun 9, 2016 20:13:18 GMT
An important announcement from LINZ concerning geodetic coordinates and the release of NZVD2016:
LINZ are improving over 80,000 coordinates on geodetic marks over the weekend of 25-26 June. This means that observations made between geodetic marks will agree much better with coordinates in the Geodetic Database, especially when observing between the PositioNZ network of continuous GNSS stations and other geodetic marks.
LINZ will also be releasing a new vertical datum at the same time. New Zealand Vertical Datum 2016 will be accurate to better than 3cm in urban areas. This is based on improved national geoid, created by including an airborne gravity dataset gathered from flights over the entire country.
See: LINZ - Landwrap June 2016 |
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Post by Brent George on Jun 29, 2016 23:27:06 GMT
Today's announcement - great news for those geodetic surveyors and also surveyors requiring reasonable heights away from 1st Order orthom,etric benchmarks....
New Vertical Datum (LINZ) |
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Post by Alex Liggett on Jul 1, 2016 8:47:52 GMT
Today's announcement - great news for those geodetic surveyors and also surveyors requiring reasonable heights away from 1st Order orthom,etric benchmarks....
New Vertical Datum (LINZ) Although in the meantime you will first need to build a Geoid Grid from coordinate triplets. We're still grappling with this at Fox & Associates. |
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Post by Brent George on Jul 4, 2016 21:57:08 GMT
Today's announcement - great news for those geodetic surveyors and also surveyors requiring reasonable heights away from 1st Order orthom,etric benchmarks....
New Vertical Datum (LINZ) Although in the meantime you will first need to build a Geoid Grid from coordinate triplets. We're still grappling with this at Fox & Associates. I am sure that our equipment manufacturers (at least) will soon supply us all with a NZ2016.GGF file.....  |
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Post by Ian Gillespie on Jul 5, 2016 4:09:08 GMT
Will this datum improve the accuracy of converting heights to local height datums? - Is there any way of knowing how accurate this conversion is?
Its all very well having a more accurate vertical datum but the council rules are still in terms of local datums.
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Post by Brent George on Jul 5, 2016 5:30:17 GMT
LINZ (and the Minister) have stated that this datum is "accurate to 3cm" - presumably relative to the control marks used.
I guess that it won't be long before NZVD2016 becomes the preferred or recommended vertical datum for all engineering and surveying works and so supersede the regional orthometric datums that we have used for decades.
The challenge will be convincing Councils and all other users using/relying on vertical datums to shift their GIS (and other) databases to it! |
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Post by Alex Liggett on Jul 6, 2016 10:12:36 GMT
Will this datum improve the accuracy of converting heights to local height datums? - Is there any way of knowing how accurate this conversion is? Its all very well having a more accurate vertical datum but the council rules are still in terms of local datums. In short, yes. The awesome folks in the LINZ Geodetic Office have published relationship grids that model the offset between NZGeoid16 and the 13 local orthometric datums. We are now just waiting for the equipment suppliers to build both the geoid model and the relationship grids into a set of geoid grids for each orthometric datum(for Trimble users that matter is in hand). The link above also specifies the accuracy of the grids. |
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Post by Alex Liggett on Jul 11, 2016 19:22:59 GMT
Individual NZGeoid16 grid files including the relationship grids for each of the 13 orthometric datums now available on the Trimble website here. Great customer service from AllTerra NZ and Trimble on this. |
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Post by Pat Sole on Nov 25, 2016 2:47:17 GMT
I see LINZ has today released NZVD2016 heights on over 44,000 marks. I cant help smiling as in the same press release it talks of a new page on their website pointing to effects of the Kaikoura earthquake. I was wondering how many of the 44,000 still have the same heights?
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