I just heard were going to adopt a new datum in Australia its called GDA 2020 , the old datum GDA 94 is now 17 years old and at 7 cm per year continental drift its time for a new datum.
V8i ss3 doesn't have this datum available in the library of datums... does SS4 have this? Does CE have it?
Will Bentley provide a stand alone file to be able to import it into Microstation to allow us to have the new datum when we need it? ( local government will want us using it within 1 - 2 years and all government spacial data will be in that datum).
Will the update file from Bentley work will both CE and V8i SS3 to SS4?
Does current Bentley Map have this datum? If so can somebody export the datum so we can add it to our datum (folder? ) so Mstn V8 etc can find it?
I know we should probably post this in the Mapping forum but I'm wanting to reach as many Microstation users as possible
I used old or original MGA94 set in in V8i placed two points from old land gate data and labelled the coords with Civtools ( 3 decimals rounded off)
then I opened in CE 13 which already had MGA 94 ( but I didn't use it why later ) jumped at it...corrected error in post from here on
" use the GSB not the 7p ,to reset the MGA94 datum and then the reproject to mga2020 for realistic project areas you get very good results"
Now I've been told by cadastral surveyors that legally they only report to + or - 0.050m or 50mm for establishment and title survey.
But my data was accurate to the mm... maybe just lucky and only used small sample for WA and 3 grid pages from Melways for victoria melbourne for my trails but I'm pretty confident its the way to go with most jobs we do for road and rail projects...
Lorys
Started msnt work 1990 - Retired Nov 2022 ( oh boy am I old )
But was long time user V8iss10 (8.11.09.919) dabbler CE update 16 (10.16.00.80)
MicroStation user since 1990 Melbourne Australia.click link to PM me
Hi Lorys,
I used the GSB (NTv2 grid file). When I tried the 7 parameter, I get differences in the 1m range.
Harping back to the old AMG84 to MGA94 days, I was always told the grid file option gave better results than the 7 parameter conversion. This concurs with the advice provided by Landgate - see above post.
I am very curious how you are getting exact conversion results with Landgate published values. Can you please breakdown how you achieved this?
Thanks,
Chris.
Christopher Albany said:<10mm range, but I'm puzzled as to why there is any differenc
" CORRECTION OF THIS POST "
SHOULD READ-
use the GDA94- GSB to CORRECT THE datum before reproject to gda2020?
our IT dept would NOT like that and make the program folder pretty much locked down...
But I had success with the CE doing 2 steps if data is old v8i MGA94 an then rename the default model name to MGA2020 so its always obvious in v8i if the datum is MGA 2020.. but for now we suggest only use on datum in your project like pre v8i olden days...
No probs, I think we need better accuracy than that.
Maybe better responses on this in the Map forum?
Regards,
Mark
OpenRoads Designer 2022 R3 (10.12) | Microstation 2023.1 | ProjectWise CE 3.4